A FreeCAD Manual

a-freecad-manual

User Manual:

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1.1
1.2
1.2.1
1.2.2
1.2.2.1
1.2.2.2
1.2.2.3
1.2.2.4
1.2.2.5
1.2.2.6
1.2.3
1.2.3.1
1.2.3.2
1.2.3.3
1.2.4
1.2.4.1
1.2.4.2
1.2.4.3
1.2.5
1.2.6
1.2.7
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.5.1
1.3.5.2
1.3.5.3
TableofContents
Introduction
DiscoveringFreeCAD
WhatisFreeCAD?
Installing
InstallingonWindows
InstallingonLinux
InstallingonMacOS
Uninstalling
Settingbasicpreferences
Installingadditionalcontent
TheFreeCADinterface
Workbenches
Theinterface
Customizingtheinterface
Navigatinginthe3Dview
Awordaboutthe3Dspace
TheFreeCAD3Dview
Selectingobjects
TheFreeCADdocument
Parametricobjects
Importandexporttootherfiletypes
WorkingwithFreeCAD
Allworkbenchesataglance
Traditionalmodeling,theCSGway
Traditional2Ddrafting
Modelingforproductdesign
Preparingmodelsfor3Dprinting
Exportingtoslicers
Convertingobjectstomeshes
UsingSlic3r
2

1.3.5.4
1.3.5.5
1.3.6
1.3.7
1.3.8
1.3.8.1
1.3.8.2
1.3.9
1.3.10
1.4
1.4.1
1.4.1.1
1.4.1.2
1.4.1.3
1.4.2
1.4.3
1.4.4
1.5
UsingtheCuraaddon
GeneratingG-code
Generating2Ddrawings
BIMmodeling
Usingspreadsheets
Readingproperties
Writingproperties
CreatingFEManalyses
Creatingrenderings
Pythonscripting
Agentleintroduction
WritingPythoncode
ManipulatingFreeCADobjects
VectorsandPlacements
Creatingandmanipulatinggeometry
Creatingparametricobjects
Creatinginterfacetools
Thecommunity
3

AFreeCADmanual

Note:ThemanualhasbeenmovedtotheofficialFreeCADwikiwhichisnowitsnewhome.

If you wish to propose edits, please do them there, as thisrepository will be kept only for

generatingtheebookversionsandwillnotbedirectlyeditedanymore.

Introduction

FreeCADisafree,open-sourceparametric3Dmodelingapplication.Itismadeprimarilyto

modelreal-worldobjects,rangingfromthesmallelectroniccomponentsuptobuildingsand

civil engineering projects, with a strong focus on 3D-printable objects. FreeCAD is free to

download,use,distributeandmodify,anditssourcecodeisopenandpublishedunderthe

verypermissiveLGPLlicense.ThedatayouproducewithFreeCADisfullyyours,andcan

berecoveredwithoutFreeCAD.

FreeCAD is also fundamentally a social project, as it is developed and maintained by a

communityofdevelopersandusersunitedbytheirpassionforFreeCAD.

This manual is an experiment at taking the opposite way from the official FreeCAD

documentation wiki. The wiki is written collaboratively by dozens of community members

and,likemostwikis,itcontainshugeamountsofinformation,butisveryhardtoaccessand

navigate by newcomers. This makes it a precious resource for reference, but not a very

practical tool to learn FreeCAD. This manual will walk you through the same information

available on the wiki. However, we hope that the more step-by-step pace, based on

examples,andthemoreunifiedtonegivenbyasmallernumberofauthors,willmakeitmore

suitableforafirstcontactwithFreeCAD,andthatitwillbecomeaperfectcompanionforthe

wiki.

This manual has been written for the current stable version of FreeCAD which is version

0.16.

AllthecontentsofthismanualarepublishedundertheCreativeCommons4.0license,and

canbefreelyused,downloaded,copied,andmodified.Thesourcefilesofthismanualare

hostedongithub.

ThisbookhasbeenwrittenmostlybyYorik,butusingalotofinformationbuiltbyFreeCAD

users, mostly from the FreeCAD wiki. The real author of this book is actually the whole

FreeCADcommunity!

Introduction

DiscoveringFreeCAD

WhatisFreeCAD?

FreeCADisanopen-sourceparametric 3Dmodelingapplication,madeprimarilyto design

real-lifeobjects.Parametricmodelingdescribesacertaintypeofmodeling,wheretheshape

of the 3D objects you design are controlled by parameters. For example, the shape of a

brickmightbecontrolledbythreeparameters:height,widthandlength.InFreeCAD,asin

otherparametricmodelers,theseparametersarepartoftheobject,andstaymodifiableat

any time, after the object has been created. Some objects can have other objects as

parameters,forexampleyoucouldhaveanobjectthattakesourbrickasinput,andcreates

a column from it. You could think of a parametric object as a small program that creates

geometryfromparameters.

FreeCADisnotdesignedforaparticularkindofwork,ortomakeacertainkindofobjects.

Instead,itallowsawiderangeofuses,andpermitsuserstoproducemodelsofallsizesand

purposes, from small electronic components to 3D-printable pieces and all the way up to

buildings.Eachofthesetaskshavedifferentdedicatedsetsoftoolsandworkflowsavailable.

FreeCADisalsomultiplatform(itrunsexactlythesamewayonWindows,MacOSandLinux

platforms), and it is open-source. Being open-source, FreeCAD benefits from the

contributions and efforts of a large community of programmers, enthusiasts and users

worldwide.FreeCADisessentiallyanapplicationbuiltbythepeoplewhouseit,insteadof

being made by a company trying to sell you a product. And of course, it also means that

FreeCADisfree,notonlytouse,butalsotodistribute,copy,modify,orevensell.

WhatisFreeCAD?

FreeCADalsobenefitsfromthehuge,accumulatedexperienceoftheopen-sourceworld.In

its bowels, it includes several other open source components, as FreeCAD itself can be

usedasacomponentinotherapplications.Italsopossessesallkindsoffeaturesthathave

become a standard in the open-source world, such as supporting a wide range of file

formats,beinghugelyscriptable,customizableandmodifiable.Allmadepossiblethrougha

dynamicandenthusiastcommunityofusers.

TheofficialwebsiteofFreeCADisathttp://www.freecadweb.org

Readmore:

AboutFreeCAD:http://www.freecadweb.org/wiki/index.php?title=About_FreeCAD

Listoffeatures:http://www.freecadweb.org/wiki/index.php?title=Feature_list

Screenshotsandusercases:http://forum.freecadweb.org/viewforum.php?f=24

WhatisFreeCAD?

Installing

FreeCADusestheLGPLlicense,whichmeansyouarefreetodownload,install,redistribute

and use FreeCAD the way you want, regardless of the type of work you'll do with it

(commercialornon-commercial).Youarenotboundtoanyclauseorrestriction,andthefiles

youproducewithitarefullyyours.Theonlythingthatthelicenseprohibits,really,istoclaim

thatyouprogrammedFreeCADyourself!

FreeCADrunswithoutanydifferenceonWindows,MacOSandLinux.However,thewaysto

install it differ slightly depending on your platform. On Windows and Mac, the FreeCAD

community provides precompiled packages (installers) ready to download, while on Linux,

the source code is made available to Linux distributions maintainers, who are then

responsibleforpackagingFreeCADfortheirspecificdistribution.Asaresult,onLinux,you

canusuallyinstallFreeCADrightfromthesoftwaremanagerapplication.

The official FreeCAD download page for Windows and Mac OS is

https://github.com/FreeCAD/FreeCAD/releases

FreeCADversions

The official releases of FreeCAD, on the page above or in your distribution's software

manager,arestableversions.However,thedevelopmentofFreeCADisfast!Newfeatures

andbugfixesareaddedalmosteverysingleday.Sinceitcansometimestakealongtime

betweenstablereleases,youmightbeinterestedintryingamorebleeding-edgeversionof

FreeCAD.Thesedevelopmentversions,orpre-releases,areuploadedfromtimetotimeto

thedownloadpagementionedabove,or,ifyouareusingUbuntu,theFreeCADcommunity

also maintains PPA (Personal Package Archives) or 'daily builds' which are regularly

updatedwiththemostrecentchanges.

If you are installing FreeCAD in a virtual machine, please be aware that the performance

mightbelow,orinsomecasesunusableduetothelimitsofOpenGLsupportonmostvirtual

machines.

InstallingonWindows

1. Downloadaninstaller(.exe)packagecorrespondingtoyourversionofWindows(32bit

or64bit)fromthedownloadpage.TheFreeCADinstallersshouldworkonanywindows

versionstartingfromWindows7.

2. Double-clickthedownloadedinstaller.

3. AcceptthetermsoftheLGPLlicense(thiswillbeoneofthefewcaseswhereyoucan

really,safelyclickthe"accept"buttonwithoutreadingthetext.Nohiddenclauses):

Installing

4. Youcanleavethedefaultpathhere,orchangeifyouwish:

5. NoneedtosetthePYTHONPATHvariable,unlessyouplantodosomeadvanced

Installing

pythonprogramming,inwhichcaseyouprobablyalreadyknowwhatthisisfor:

6. Duringtheinstallation,acoupleofadditionalcomponents,whicharebundledinsidethe

installer,willbeinstalledtoo:

Installing

7. That'sit,FreeCADisinstalled.Youwillfinditinyourstartmenu.

Installingadevelopmentversion

Installing

PackagingFreeCAD andcreatingan installertakes sometime and dedication,so usually,

development(alsocalledpre-release)versionsareprovidedas.zip(or.7z)archives.These

don't need to be installed, just unpack them and lauch FreeCAD by double-clicking the

FreeCAD.exefilethatyouwillfindinside.Thisalsoallowsyoutokeepboththestableand

"unstable"versionstogetheronthesamecomputer.

InstallingonLinux

On most modern Linux distributions (Ubuntu, Fedora, OpenSUSE, Debian, Mint,

Elementary, etc), FreeCAD can be installed with the click of a button, directly from the

software management application provided by your distribution (the aspect of it can differ

fromtheimagesbelow,eachdistributionusesitsowntool).

1. Openthesoftwaremanagerandsearchfor"freecad":

2. Clickthe"install"buttonandthat'sit,FreeCADgetsinstalled.Don'tforgettorateit

afterwards!

Installing

Alternativeways

OneofthebigjoysofusingLinuxisthemultitudeofpossibilitiestotailoryoursoftware,so

don't restrain yourself. On Ubuntu and derivatives, FreeCAD can also be installed from a

PPA maintained by the FreeCAD community (it contains both stable and development

versions) and since this is open-source software, you can also easily compile FreeCAD

yourself.

InstallingonMacOS

InstallingFreeCADonMacOSXisnowadaysaseasyasonotherplatforms.However,since

therearelesspeopleinthecommunitywhoownaMac,theavailablepackagesoftenlaga

coupleofversionsbehindtheotherplatforms.

1. Downloadazippedpackagecorrespondingtoyourversionfromthedownloadpage.

2. OpentheDownloadsfolder,andexpandthedownloadedzipfile:

Installing

3. DragtheFreeCADapplicationfrominsidetheziptotheApplicationsfolder:

4. That'sit,FreeCADisinstalled!

Installing

5. IfthesystempreventsFreeCADtolaunch,duetorestrictedpermissionsforapplications

notcomingfromtheAppstore,youwillneedtoenableitinthesystemsettings:

Installing

Uninstalling

Hopefullyyouwon'twanttodothat,butitisgoodtoknowanyway.OnWindowsandLinux,

uninstalling FreeCAD is very straightforward. Use the standard "remove software" option

foundinthecontrol panelonWindows,or removeitwiththe samesoftwaremanageryou

used to install FreeCAD on Linux. On Mac, all you need to do is remove it from the

Applicationsfolder.

Settingbasicpreferences

Once FreeCAD is installed, you might want to open it and set a couple of preferences.

Preferences settings in FreeCAD are located under menu Edit -> Preferences. You can

browse through the different pages to see if there is anything else you would want to

change,buthereareacoupleofbasicones:

1. Language:FreeCADwillautomaticallypickthelanguageofyouroperatingsystem,but

youmightwanttochangethat.FreeCADisalmostfullytranslatedto5or6languages,

plusmanyothersthatareatthemomentonlypartiallytranslated.Youcaneasilyhelpto

translateFreeCAD.

Installing

2. Auto-loadmodule:Normally,FreeCADwillstartshowingyouthestartcenterpage.

YoucanskipthisandbeginaFreeCADsessiondirectlyintheworkbenchofyour

choice.Workbencheswillbeexplainedindetailinthenextchapter.

3. Createdocumentatstartup:Combinedwiththeoptionabove,thisstartsFreeCAD

readyforwork.

Installing

4. Storageoptions:Asanycomplexapplication,FreeCADmightcrashfromtimetotime.

Hereyoucanconfigureafewoptionsthatwillhelpyoutorecoveryourworkincaseofa

crash.

5. Authoringandlicense:Youcansetthedefaultsettingsthatwillbeusedforyournew

files.Considermakingyourfilesshareablerightfromthestart,byusingafriendlier,

copyleftlicenselikeCreativeCommons.

6. Redirectpythonmessagestooutputview:Thesetwooptionsarealwaysgoodto

mark,astheywillpermityoutoseewhat'swrongintheReportViewwhenthere'sa

problemwithrunningaparticularpythonscript.

Installing

7. Units:Hereyoucansetthedefaultunitsyouwishtouse.Itwillbeeasierworkingthe

exampleslater,tostayinMKS.

Installing

Installingadditionalcontent

As the FreeCAD project and its community grows quickly, and also because it is easy to

extend, external contributions and side-projects made by community members and other

enthusiastsbegintoappeareverywhereontheinternet.Thereisaneffortgoingontogather

all these interesting additions in one place, on the FreeCAD github page. There, among

otherthings,youwillfind:

1. APartslibrary,whichcontainsallkindsofusefulmodels,orpiecesofmodels,created

byFreeCADusersthatcanbefreelyusedinyourprojects.Thelibrarycanbeusedand

accessedrightfrominsideyourFreeCADinstallation.

2. Acollectionofaddons,mostofthemadditionalworkbenches,thatextendthe

functionalityofFreeCADforcertaintasks.Instructionsforinstallingaregivenoneach

separateaddonpage.

3. Acollectionofmacros,whicharealsoavailableontheFreeCADwikialongwith

documentationabouthowtousethem.Thewikicontainsmanymoremacros.

Installing

IfyouareusingUbuntuoranyofitsderivatives,theFreeCAD-extrasPPAcontainsmostof

theseaddons.Onotherplatforms,anyoftheaddons,includingthePartslibrary,caneasily

beinstalledusinganaddon-installermacroprovidedintheaddonsrepository.Thefollowing

procedureshowshowtoinstalltheaddon-installer(othermacroscanbeinstalledthesame

way)

1. Downloadtheaddons-installer.FCMacrofilefrom

https://github.com/FreeCAD/FreeCAD-addonsbyclickingit,thenright-clickingthe

"RAW"button,andchoosing"Saveas".

2. PlacethemacroinyourFreeCADMacrosdestinationpath.YouFreeCADMacros

destinationpathisindicatedatthebottomoftheExecutemacrodialoginFreeCAD:

3. CloseandreopentheExecutemacrodialog,andstartthe

addons_installer.FCMacro.Theinstallerwilllaunch,fromwhereyoucaninstall,

updateanduninstallanyoftheaddons:

Installing

Readmore

Moredownloadoptions:http://www.freecadweb.org/wiki/index.php?title=Download

Detailedinstallationinstructions:http://www.freecadweb.org/wiki/index.php?

title=Installing

FreeCADPPAforUbuntu:https://launchpad.net/~freecad-maintainers

FreeCADaddonsPPAforUbuntu:https://launchpad.net/freecad-extras

CompileFreeCADyourself:http://www.freecadweb.org/wiki/index.php?title=Compiling

FreeCADtranslations:https://crowdin.com/project/freecad

FreeCADgithubpage:https://github.com/FreeCAD

Installing

TheFreeCADinterface

FreeCADusestheQtframework)todrawandmanageitsinterface.Thisframeworkisused

inawiderangeofapplications,sotheFreeCADinterfaceisveryclassicalandpresentsno

particular difficulty to understand. Most buttons are standard and will be found where you

expectthem(File->Open,Edit->Paste,etc).HereisthelookofFreeCADwhenyouopen

itforthefirsttime,justafterinstalling,showingyouthestartcenter:

The start center is a convenient "welcome screen", that shows useful information for

newcomers, like the latest files you have been working on, what's new in the FreeCAD

world, or quick info about the most common Workbenches. It will also notify you if a new

stableversionofFreeCADisavailable.

ClosetheStartPage tab(clickonthetab xnearthebottom)and createanewdocument

(Ctrl-N):

TheFreeCADinterface

Workbenches

Notethatsomeoftheiconshavechangedbetweenthetwoscreencapturesabove.Thisis

where the most important concept used in the FreeCAD interface comes into play:

Workbenches.

Workbenchesaregroupoftools(toolbarbuttons,menus,andotherinterfacecontrols)that

are grouped together by specialty. Think of a workshop where you have different people

workingtogether:Apersonwhoworkswithmetal,anotherwithwood.Eachofthemhas,in

their workshop, a separate table with specific tools for his/her job. However, they can all

workonthesameobjects.ThesamehappensinFreeCAD.

ThemostimportantcontroloftheFreeCADinterfaceistheWorkbenchselector,whichyou

usetoswitchfromoneWorkbenchtoanother:

TheFreeCADinterface

Workbenches often confuse new users, since it's not always easy to know in which

Workbench to look for a specific tool. But they are quick to learn, and after a short while,

they will feel natural. New users quickly realize Workbenches are a convenient way to

organizethemultitudeoftoolsFreeCADhastooffer.Inaddition,Workbenchesarealsofully

customizable(seebelow).

Laterinthismanual,youwillfindatableshowingtypicalWorkbenchcontents.

Theinterface

Let'shaveabetterlookatthedifferentpartsoftheinterface:

TheFreeCADinterface

The3Dviewisthemaincomponentoftheinterface.Itcanbeundockedoutofthemain

window,youcanhaveseveralviewsofthesamedocument(orsameobjects),or

severaldocumentsopenedatthesametime.Youcanselectobjectsorpartsofobjects

byclickingthem,andyoucanpan,zoomandrotatetheviewwiththemousebuttons.

Thiswillbeexplainedfurtherinthenextchapter.

Thecomboviewontheleftsideofthewindow,hastwotabs:

TheModeltabshowsyouthecontentsandstructureofyourdocument(seeabove)

andtheproperties(orparameters)oftheselectedobject(s)(seebelow.)These

ModelTabpropertiesareseparatedintwocategories:

Data(propertieswhichconcernthegeometryitself)

View(propertiesthataffecthowthegeometrylookslikeonscreen).

TheTaskstabiswhereFreeCADwillpromptyouforvaluesspecifictothetool

you'recurrentlyusingatthetime—forexample,enteringa'length'valuewhenthe

Linetoolisbeingused.ItwillcloseautomaticallyafterpressingtheOK(orCancel)

button.Also,bydouble-clickingtherelatedobjectinthecomboview,mosttoolswill

allowyoutoreopenthattaskpanelinordertomodifythesettings.

Thereportviewisnormallyhidden,butitisagoodideatoleaveopenasitwilllistany

information,warningsorerrorstohelpyoudecipher(ordebug)whatyoumayhave

donewrong.(Viewmenu->Panels->ReportViewchecked)

ThePythonconsoleisalsohiddenbydefault.Thisiswhereyoucaninteractwiththe

contentsofthedocumentusingthePythonlanguage.Sinceeveryactionyoudoonthe

FreeCADinterfaceactuallyexecutesapieceofPythoncode,havingthisopenallows

youtowatchthecodeunfoldinrealtime—allowingyouawonderfulandeasywayto

TheFreeCADinterface

learnalittlePythonontheway,almostwithoutnoticingit.(Viewmenu->Panels->

PythonConsolechecked)

Anyofthepanelsabovecanbeturnedon/offfrommenuView->Panels.

Customizingtheinterface

TheinterfaceofFreeCADisdeeplycustomizable.Allpanelsandtoolbarscanbemovedto

differentplacesorstackedonewithanother.Theycanalsobeclosedandreopenedwhen

neededfromtheViewmenuorbyright-clickingonanemptyareaoftheinterface.Thereare,

however,manymoreoptionsavailable,suchascreatingcustomtoolbarswithtoolsfromany

oftheWorkbenches,orassigningandchangingkeyboardshortcuts.

TheseadvancedcustomizationoptionsareavailabefromtheTools->Customizemenu:

TheFreeCADinterface

Readmore

GettingstartedwithFreeCAD:http://www.freecadweb.org/wiki/index.php?

title=Getting_started

Customizingtheinterface:http://www.freecadweb.org/wiki/index.php?

title=Interface_Customization

Workbenches:http://www.freecadweb.org/wiki/index.php?title=Workbenches

MoreaboutPython:https://www.python.org

TheFreeCADinterface

Navigatinginthe3Dview

Awordaboutthe3Dspace

Ifthisisyourfirstcontactwitha3Dapplication,youwillneedtograbsomeconceptsfirst.If

not,youcansafelyskipthissection.

TheFreeCAD3Dspace isaneuclidianspace. Ithas an originpoint andthree axes:X, Y

andZ.Ifyoulookatyourscenefromabove,conventionally,theXaxispointstotheright,the

Yaxistotheback,andtheZaxisupwards.InthelowerrightcorneroftheFreeCADview,

youcanalwaysseefromwhereyouareviewingthescene:

Everypointofeveryobjectthatexistsinthatspacecanbelocatedbyits(x,y,z)coordinates.

Forexample,apointwithcoordinates(2,3,1)willlieat2unitsontheXaxis,3unitsontheY

axis,and1unitontheZaxis:

Youcanlookatthatscenefromanyangle,likeifyouwereholdingacamera.Thatcamera

canbemovedleft,right,upanddown(pan),rotatedaroundwhatitislookingat(rotate)and

broughtcloserorfurtherfromthescene(zoom).

TheFreeCAD3Dview

Navigatinginthe3Dview

NavigatingintheFreeCAD3Dviewcanbedonewithamouse,aSpaceNavigatordevice,

thekeyboard,atouchpad,oracombinationofthose.FreeCADcanuseseveralnavigation

modes,whichdeterminehowthethreebasicviewmanipulationoperations(pan,rotateand

zoom) are done, as well as how to select objects on the screen. Navigation modes are

accessedfromthePreferencesscreen,ordirectlybyright-clickinganywhereonthe3Dview:

Eachofthesemodesattributesdifferentmousebuttons,ormouse+keyboardcombinations,

or mouse gestures, to these four operations. The following table shows the principal

availablemodes:

Navigatinginthe3Dview

Mode Pan Rotate Zoom Select

Inventor

CTRL+

CAD

(default)

Blender

SHIFT+

Touchpad

SHIFT+ ALT+

PGUP/

PGDOWN

Gesture

+

DRAG

+

DRAG

Alternatively,somekeyboardcontrolsarealwaysavailable,nomatterthenavigationmode:

CTRL+andCTRL-tozoominandzoomout

Thearrowkeystoshift(pan)theviewleft/rightandup/down

thenumerickeys,1to6,forthesixstandardviews,top,front,right,bottom,backand

left

Owillsetthecamarainorthographicmode,

whilePsetsitinperspectivemode.

CTRLwillallowyoutoselectmorethanoneobjectorelement

ThesecontrolsarealsoavailablefromtheViewmenuandsomefromtheViewtoolbar.

Navigatinginthe3Dview

Selectingobjects

Objects in the 3D view can be selected by clicking them with the corresponding mouse

button, depending on the navigation mode. (For the rest of the manual we'll assume the

defaultCADnavigation.)Asingleclickwillselecttheobject,andoneofitssubcomponents

(edge, face, vertex). Double-clicking will select the object, and all its subcomponents. You

can select more than one subcomponent, or even different subcomponents from different

objects, by pressing the CTRL key. With multiple items selected, keeping the CTRL key

pressed, and pressing a selected item removes it from the selection. Clicking with the

selectionbuttononanemptyportionofthe3Dviewwilldeselecteverything.

Apanelcalled"Selectionview",availablefromtheViewmenu,canalsobeturnedon,which

showsyouwhatiscurrentlyselected:

YoucanalsousetheSelectionViewtoselectobjectsbysearchingforaparticularobject.

Readmore

TheFreeCADnavigationmodes:http://www.freecadweb.org/wiki/index.php?

title=Mouse_Model

Navigatinginthe3Dview

TheFreeCADdocument

A FreeCAD document contains all the objects of your scene. It can contain groups and

objectsmadewithanyworkbench.Youcanthereforeswitchbetweenworkbenches,andstill

work on the same document and/or objects within that document. The document is what

getssavedtodiskwhenyousaveyourwork.Youcanalsoopenseveraldocumentsatthe

sametimeinFreeCAD,andopenseveralviewsofthesamedocument.

Inside the document, the objects can be moved into groups, and have a unique name.

Managinggroups,objectsandobjectnamesisdonemainlyfromtheTreeview.There,you

cancreategroups,moveobjectstogroups,deleteobjectsorgroups.Byright-clickinginthe

treevieworonanobject,youcanrenameobjects,changetheircolor,hideorshowthem,or

possiblyotheroperations,dependingonthecurrentworkbench.

TheFreeCADdocument

TheobjectsinsideaFreeCADdocumentcanbeofdifferenttypes.Eachworkbenchcanadd

its own types of objects, for example the Mesh Workbench adds mesh objects, the Part

WorkbenchaddsPartobjects,etc.

Thereisalwaysoneandonlyoneactivedocument.That'sthedocumentthatappearsinthe

current3Dview,the documentyouarecurrently workingon.Ifyou switchtabstoanother

document, that one becomes the active document. Most operations always work on the

activedocument.

FreeCADdocumentsaresavedwiththe.FcStdextension,whichisazip-basedcompound

format,similartoLibreOffice. If something goes very wrong, it is often possible to unzip it

andfixtheproblemorrescuethedata.

Readmore

TheFreeCADdocument:http://www.freecadweb.org/wiki/index.php?

title=Document_structure

TheFcStdfileformat:http://www.freecadweb.org/wiki/index.php?

title=File_Format_FCStd

TheFreeCADdocument

Parametricobjects

FreeCAD is designed for parametric modeling. This means that the geometry that you

create, instead of being freely sculptable, is produced by rules and parameters. For

example, a cylinder might be produced from a radius and a height. With these two

parameters,theprogramhasenoughinformationtobuildthecylinder.

Parametricobjects,inFreeCAD,areinrealitysmallpiecesofaprogramthatrunwhenever

oneoftheparametershaschanged.Objectscanhavealotofdifferentkindsofparameters:

numbers (integers like 1, 2, 3 or floating-point values like 3.1416), real-world sizes (1mm,

2.4m,4.5ft),(x,y,z)coordinates,textstrings("hello!")orevenanotherobject.

Thislasttypeallowsquicklybuildingcomplexchainsofoperations,eachnewobjectbeing

basedonapreviousone,addingnewfeaturestoit.

In the example below, a solid, cubic object (Pad) is based on a rectangular 2D shape

(Sketch)andhasanextrusiondistance.Withthesetwoproperties,itproducesasolidshape

byextrudingthebaseshapebythegivendistance.Youcanthenusethisobjectasabase

forfurtheroperations,suchasdrawinganew2Dshapeononeofitsfaces(Sketch001)and

thenmakingasubtraction(Pocket),untilarrivingatyourfinalobject.

Alltheintermediaryoperations(2Dshapes,pad,pocket,etc)arestillthere,andyoucanstill

change any of their parameters anytime. The whole chain will be rebuilt (recomputed)

wheneverneeded.

Parametricobjects

Twoimportantthingsarenecessarytoknow:

1. Recomputationisnotalwaysautomatic.Heavyoperations,thatmightmodifyabig

portionofyourdocument,andthereforetakesometime,arenotperformed

automatically.Instead,theobject(andalltheobjectsthatdependonit)willbemarked

forrecomputation(asmallblueiconappearsontheminthetreeview).Youmustthen

presstherecomputebutton(F5keyorthetwobluearrowspointingheadtotail)tohave

allthemarkedobjectsrecomputed.

2. Thedependencytreemustalwaysflowinthesamedirection.Loopsareforbidden.You

canhaveobjectAwhichdependsonobjectBwhichdependonobjectC.Butyou

cannothaveobjectAwhichdependsonobjectBwhichdependsonobjectA.That

wouldbeacirculardependency.However,youcanhavemanyobjectsthatdependon

thesameobject,forexampleobjectsBandCbothdependonA.MenuTools->

Dependencygraphshowsyouadependencydiagramliketheimageabove.Itcanbe

usefultodetectproblems.

NotallobjectsareparametricinFreeCAD.Often,thegeometrythatyouimportfromother

files won't contain any parameter, and will be simple, non-parametric objects. However,

thesecanoftenbe usedasabase,orstartingpointfor newlycreatedparametricobjects,

depending,ofcourse,onwhattheparametricobjectrequiresandthequalityoftheimported

geometry.

Parametricobjects

Allobjects,however, parametricor not,willhave acouple ofbasicparameters, suchasa

Name, which is unique in the document and cannot be edited, a Label, which is a user-

definednamethatcanbeedited,andaplacement,whichholdsitspositioninthe3Dspace.

Finally,itisworthnotingthatcustomparametricobjectsareeasytoprograminpython.

Readmore

Thepropertieseditor:http://www.freecadweb.org/wiki/index.php?title=Property_editor

Howtoprogramparametricobjects:http://www.freecadweb.org/wiki/index.php?

title=Scripted_objects

PositioningobjectsinFreeCAD:http://www.freecadweb.org/wiki/index.php?

title=Placement

Enablingthedependencygraph:http://www.freecadweb.org/wiki/index.php?

title=Std_DependencyGraph

Parametricobjects

Importandexporttootherfiletypes

FreeCADcanimportandexporttomanyfiletypes.Hereisalistofthemostimportantones

withashortdescriptionoftheavailablefeatures:

Format Import Export Notes

STEP Yes Yes

Thisisthemostfaithfulimport/exportformatavailable,

sinceitsupportssolidgeometryandNURBS.Useit

wheneverpossible.

IGES Yes Yes Anoldersolidformat,alsoverywellsupported.Some

olderapplicationsdon'tsupportSTEPbuthaveIGES.

BREP Yes Yes ThenativeformatofOpenCasCade,FreeCAD's

geometrykernel.

DXF Yes Yes

AnopenformatmaintainedbyAutodesk.Sincethe3D

datainsideaDXFfileisencodedinaproprietary

format,FreeCADcanonlyimport/export2Ddata

to/fromthisformat.

DWG Yes Yes

Aproprietaryfileformat.Requirestheinstallationof

theTeighaFileConverterutility.Thisformatsuffers

fromthesameproprietarylimitationsasDXF.

OBJ Yes Yes

Amesh-basedformat.Canonlycontaintriangulated

meshes.AllsolidandNURBS-basedobjectsof

FreeCADwillbeconvertedtomeshonexport.An

alternativeexporterisprovidedbytheArch

workbench,moresuitedtotheexportofarchitectural

models.

DAE Yes Yes

Themainimport/exportformatofSketchup.Canonly

containtriangulatedmeshes.AllsolidandNURBS-

basedobjectsofFreeCADwillbeconvertedtomesh

onexport.

STL Yes Yes

Amesh-basedformat,commonlyusedfor3Dprinting.

Canonlycontaintriangulatedmeshes.Allsolidand

NURBS-basedobjectsofFreeCADwillbeconverted

tomeshonexport.

PLY Yes Yes

Anoldermesh-basedformat.Canonlycontain

triangulatedmeshes.AllsolidandNURBS-based

objectsofFreeCADwillbeconvertedtomeshon

export.

IFC Yes Yes

IndustryFoundationClasses.Requirestheinstallation

ofIfcOpenShell-python.TheIFCformatandits

compatibilitywithotherapplicationsisacomplex

affair,usewithcare.

Importandexporttootherfiletypes

SVG Yes Yes Anexcellent,widespread2Dgraphicsformat

VRML Yes Yes Aratheroldmesh-basedwebformat.

GCODE Yes Yes

FreeCADcanimportandexportto/fromseveral

flavorsofGCode,(akaRS-274)butonlyasmall

numberofmachinesaresupportedatthemoment.

CSG Yes No OpenSCAD'sCSG(ConstructiveSolidGeometry)

format.

Some of these file formats have options. These can be configured from menu Edit ->

Preferences -> Import/export:

Readmore

AllfileformatssupportedbyFreeCAD:http://www.freecadweb.org/wiki/index.php?

title=Import_Export

WorkingwithDXFfilesinFreeCAD:http://www.freecadweb.org/wiki/index.php?

title=Draft_DXF

EnablingDXFandDWGsupport:http://www.freecadweb.org/wiki/index.php?

title=Dxf_Importer_Install

WorkingwithSVGfilesinFreeCAD:http://www.freecadweb.org/wiki/index.php?

title=Draft_SVG

Importandexporttootherfiletypes

ImportingandexportingtoIFC:http://www.freecadweb.org/wiki/index.php?

title=Arch_IFC

OpenCasCade:http://www.opencascade.com

TeighaFileConverter:https://www.opendesign.com/guestfiles

TheIFCformat:http://www.buildingsmart-tech.org/ifc/IFC4/final/html/index.htm

IfcOpenShell:http://ifcopenshell.org/

Importandexporttootherfiletypes

WorkingwithFreeCAD

Allworkbenchesataglance

OneofthebiggestdifficultyfornewusersofFreeCAD,istoknowinwhichworkbenchtofind

aspecifictool.Thetablebelowwillgiveyouanoverviewofthemostimportantworkbenches

andtheir tools.Referto eachworkbench page inthe FreeCAD documentationfor a more

completelist.

Fourworkbenchesarealsodesignedtoworkinpairs,andoneofthemisfullyincludedinto

theother:ArchcontainsalltheDrafttools,andPartDesignalltheSketchertools.However,

forclarity,theyareseparatedbelow.

Part

The Part Workbench provides basic tools for working with solid parts: primitives, such as

cubeandsphere,andsimplegeometricoperationsandbooleanoperations.Beingthemain

anchorpointwithOpenCasCade,thePartworkbenchprovidesthefoundationofFreeCAD's

geometrysystem,andalmostallotherworkbenchesproducePart-basedgeometry.

Allworkbenchesataglance

Tool Description Tool Description
Box Drawsabox
Cone
Drawsacone
Cylinder
Drawsacylinder
Sphere
Drawsasphere
Torus
Drawsatorus(ring) Create
Primitives
Createsvariousother
parametricgeometric
primitives
Shape
Builder
Createmorecomplex
shapesfromprimitives Fuse
Fuses(unions)twoobjects
Common
Extractsthecommon
(intersection)partoftwo
objects Cut
Cuts(subtracts)oneobject
fromanother
Join
Connect
Connectsinteriorsofwalled
objects Join
Embed
Embedsawalledobjectinto
anotherwalledobject
Join
Cutout
Createsacutoutinawall
ofanobjectforanother
walledobject Extrude
Extrudesplanarfacesofan
object
Fillet
Fillets(rounds)edgesofan
object Revolve
Createsasolidbyrevolving
anotherobject(notsolid)
aroundanaxis
Section
Createsasectionby
intersectinganobjectwith
asectionplane Section
Cross
Createsmultiplecross
sectionsalonganobject
Chamfer
Chamfersedgesofan
object Mirror
Mirrorstheselectedobject
onagivenmirrorplane
Ruled
Surface
Createaruledsurface
betweenselectedcurves Sweep
Sweepsoneormoreprofiles
alongapath
Loft
Loftsfromoneprofileto
another Offset
Createsascaledcopyofthe
originalobject
Thickness
Assignathicknesstothe
facesofashape
Allworkbenchesataglance
44

Draft

TheDraftWorkbenchprovidestoolstodobasic2DCADdraftingtasks:lines,circles,etc...

andaseriesofgenerichandytoolssuchasmove,rotateorscale.Italsoprovidesseveral

drawingaids, such asgrid and snapping.It is principallymeant to drawthe guidelines for

Archobjects,butalsoservesasFreeCAD's"swissknife".

Tool Description Tool Description

Line

Drawsaline

segmentbetween2

points Wire

Drawsalinemadeofmultiple

linesegments(polyline)

Circle

Drawsacirclefrom

centerandradius

Arc

Drawsanarcsegmentfrom

center,radius,startangleand

endangle

Ellipse

Drawsanellipse

fromtwocorner

points Polygon

Drawsaregularpolygonfroma

centerandaradius

Rectangle

Drawsarectangle

from2opposite

points Text

Drawsamulti-linetext

annotation

Dimension

Drawsadimension

annotation

BSpline

DrawsaB-Splinefromaseries

ofpoints

Point

Insertsasingle

point Shape

String

TheShapeStringtoolinsertsa

compoundshaperepresentinga

textstringatagivenpointinthe

currentdocument

Facebinder

Createsanew

objectfrom

selectedfaceson

existingobjects

Bezier

Curve

DrawsaBeziercurvefroma

seriesofpoints

Move

Movesorcopies

objectsfromone

locationtoanother Rotate

Rotatesobjectsbyacertain

anglearoundapoint

Allworkbenchesataglance

Offset
Offsetsanobjectto
acertaindistance
Trimex
Trims,extendsorextrudesan
object
Upgrade
Turnsorjoins
objectsintoa
higher-levelobject Downgrade
Turnsorsepartesobjectsinto
lower-levelobjects
Scale
Scalesobjectsin
relationtoapoint Shape2D
View
Createsa2Dobjectwhichisa
flattenedviewofanotherobject
Draft2Sketch
ConvertsaDraft
objecttoaSketch
andvice-versa Array
Createsapolarorrectangular
arrayfromanobject
PathArray
Createsanarray
fromanobjectby
placingcopies
alongapath
Clone Createslinkedcopiesofobjects
Mirror
Mirrorsobjects
acrossaline
Sketcher
The Sketcher Workbench contains tools to build and edit complex 2D objects, called
sketches.Thegeometryinsidethesesketchescanbepreciselypositionedandrelationedby
the use of constraints. They are meant primarily to be the building blocks of PartDesign
geometry,butareusefuleverywhereinFreeCAD.
Tool Description Tool Description
Point Drawsapoint Lineby
2points
Drawsalinesegment
from2points
Arc
Drawsanarcsegmentfrom
center,radius,startangle
andendangle
Arcby3
points
Drawsanarcsegment
fromtwoendpoints
andanotherpointon
thecircumference
Circle
Drawsacirclefromcenter
andradius Circleby
3points
Drawsacirclefrom
threepointsonthe
circumference
Drawsanellipsebycenter
point,majorradiuspointand Ellipse
Drawsanellipseby
majordiameter(2
Allworkbenchesataglance
46

center minorradiuspoint by3points points)andminor
radiuspoint
Arc
ofellipse
Drawsanarcofellipseby
centerpoint,majorradius
point,startingpointand
endingpoint
Polyline
Drawsalinemadeof
multiplelinesegments.
Severaldrawing
modesavailable
Rectangle
Drawsarectanglefrom2
oppositepoints Triangle
Drawsaregular
triangleinscribedina
constructiongeometry
circle
Square
Drawsaregularsquare
inscribedinaconstruction
geometrycircle Pentagon
Drawsaregular
pentagoninscribedin
aconstruction
geometrycircle
Hexagon
Drawsaregularhexagon
inscribedinaconstruction
geometrycircle Heptagon
Drawsaregular
heptagoninscribedin
aconstruction
geometrycircle
Octagon
Drawsaregularoctagon
inscribedinaconstruction
geometrycircle Slot
Drawsanovalby
selectingthecenterof
onesemicircleandan
endpointoftheother
semicircle
Fillet
Makesafilletbetweentwo
linesjoinedatonepoint Trim
Trimsaline,circleor
arcwithrespecttoa
clickedpoint
External
Geometry
Createsanedgelinkedto
externalgeometry Construction
Mode
Togglesanelement
to/fromconstruction
mode.Aconstruction
objectwillnotbeused
ina3Dgeometry
operationandisonly
visiblewhileeditingthe
Sketchthatcontainsit
Coincident
constraint
Affixesapointonto
(coincidentwith)oneormore
otherpoints.
PointOn
Object
constraint
Affixesapointonto
anotherobjectsuchas
aline,arc,oraxis.
Vertical
constraint
Constrainstheselectedlines
orpolylineelementstoatrue
verticalorientation.More
thanoneobjectcanbe
selectedbeforeapplyingthis
constraint.
Horizontal
constraint
Constrainsthe
selectedlinesor
polylineelementstoa
truehorizontal
orientation.Morethan
oneobjectcanbe
selectedbefore
applyingthis
constraint.
Allworkbenchesataglance
47

constraint.

Parallel

constraint

Constrainstwoormorelines

paralleltooneanother. Perpendicular

constraint

Constrainstwolines

perpendiculartoone

another,orconstrains

alineperpendicularto

anarcendpoint.

Tangent

constraint

Createsatangentconstraint

betweentwoselected

entities,oraco-linear

constraintbetweentwoline

segments.

Equal

Length

constraint

Constrainstwo

selectedentitiesequal

tooneanother.Ifused

oncirclesorarcstheir

radiiwillbesetequal.

Symmetric

constraint

Constrainstwopoints

symmetricallyaboutaline,

orconstrainsthefirsttwo

selectedpoints

symmetricallyaboutathird

selectedpoint.

Lock

constraint

Constrainsthe

selecteditemby

settingverticaland

horizontaldistances

relativetotheorigin,

therebylockingthe

locationofthatitem

Horizontal

Distance

constraint

Fixesthehorizontaldistance

betweentwopointsorline

endpoints.Ifonlyoneitemis

selected,thedistanceisset

totheorigin.

Vertical

Distance

constraint

Fixesthevertical

distancebetween2

pointsorline

endpoints.Ifonlyone

itemisselected,the

distanceissettothe

origin.

Length

constraint

Definesthedistanceofa

selectedlinebyconstraining

itslength,ordefinesthe

distancebetweentwopoints

byconstrainingthedistance

betweenthem.

Radius

constraint

Definestheradiusofa

selectedarcorcircle

byconstrainingthe

radius.

Internal

Angle

constraint

Definestheinternalangle

betweentwoselectedlines.

Snell's

Law

constraint

Constrainstwolinesto

obeyarefractionlaw

tosimulatethelight

goingthroughan

interface

Internal

Alignment

constraint

Alignsselectedelementsto

selectedshape(e.g.alineto

becomemajoraxisofan

ellipse)

Map

sketchtoface

Mapsasketchtothe

previouslyselected

faceofasolid

Merge

Mergetwoormoresketches Mirror

Mirrorsselected

elementsofasketch

PartDesign

Allworkbenchesataglance

ThePartDesignWorkbenchcontainsadvancedtoolstobuildsolidparts.Italsocontainsall

thetoolsfromthesketcher.Sinceitcanonlyproducessolidshapes(therulenumberoneof

Part Design), it is the main workbench to use when designing pieces (parts) to be

manufacturedor3D-printed,asyouwillalwaysobtainaprintableobject.

Tool Description Tool Description

Pad

Extrudesasolidobject

fromaselectedsketch Pocket

Createsapocketfroma

selectedsketch.The

sketchmustbemapped

toanexistingsolid

object'sface

Revolution

Createsasolidby

revolvingasketcharound

anaxis Groove

Createsagrooveby

revolvingasketch

aroundanaxis

Fillet

Fillets(rounds)edgesof

anobject Chamfer

Chamfersedgesofan

object

Draft

Appliesangulardraftto

facesofanobject Mirrored

Mirrorsfeaturesona

planeorface

Linear

Pattern

Createsalinearpatternof

features Polar

Pattern

Createsapolarpattern

offeatures

Scaled

Scalesfeaturestoa

differentsize MultiTransform

Allowscreatinga

patternwithany

combinationoftheother

transformations

Shaft

wizard

Generatesashaftfroma

tableofvaluesandallows

toanalyzeforcesand

moments

Involute

Gearwizard

Allowsyoutocreate

severaltypesofgears

Arch

The Arch Workbench contains tools to work with BIM projects (civil engineering and

architecture). It also contains all the tools from the Draft workbench. The main use of the

Arch Workbench is to create BIM objects or give BIM attributes to objects built with other

workbenches,inordertoexportthemtoIFC.

Allworkbenchesataglance

Tool Description Tool Description
Wall
Createsawallfrom
scratchorusinga
selectedobjectasa
base Structure
Createsastructural
elementfromscratchor
usingaselectedobjectas
abase
Reinforcement
Bar
Createsa
reinforcementbarina
selectedstructural
element Floor
Createsafloorincluding
selectedobjects
Building
Createsabuilding
includingselected
objects Site
Createsasiteincluding
selectedobjects
Window
Createsawindow
usingaselectedobject
asabase Section
Plane
Addsasectionplane
objecttothedocument
Axes
Addsanaxessystem
tothedocument Roof
Createsaslopedrooffrom
aselectedface
Space
Createsaspaceobject
inthedocument Stairs
Createsastairsobjectin
thedocument
Panel
Createsapanelobject
fromaselected2D
object Frame
Createsaframeobject
fromaselectedlayout
Equipment
Createsanequipment
orfurnitureobject Set
Material
Attributesamaterialto
selectedobjects
Schedule
Createsdifferenttypes
ofschedules Cut
Plane
Cutanobjectaccordingto
aplan.
Add
Component
Addsobjectstoa
component Remove
Component
Subtractsorremoves
objectsfromacomponent
Survey
Mode
Entersorleaves
surveyingmode
Drawing
Allworkbenchesataglance
50

TheDrawingWorkbenchhandlesthecreationandmanipulationof2Ddrawingsheets,used

for displaying views of your 3D work in 2D. These sheets can then be exported to 2D

applicationsinSVGorDXFformats,toaPDFfileorprinted.

Tool Description Tool Description

New

sheet

Createsanewdrawing

sheet Insert

view

Insertsaviewoftheselected

objectintheactivedrawing

sheet

Annotation

Addsanannotationtothe

currentdrawingsheet Clip

Addsaclipgrouptothecurrent

drawingsheet

Browser

preview

Opensapreviewofthe

currentsheetinthebrowser Ortho

Views

Automaticallycreates

orthographicviewsofanobject

onthecurrentdrawingsheet

Symbol

AddsthecontentsofaSVG

fileasasymbolonthe

currentdrawingsheet Draft

View

InsertsaspecialDraftviewof

theselectedobjectinthe

currentdrawingsheet

Export

Savesthecurrentsheetas

aSVGfile

Otherbuilt-inworkbenches

Although the above summarizes the most important tools of FreeCAD, many more

workbenchesareavailable,amongthem:

TheMeshWorkbenchallowstoworkwithpolygonmeshes.Althoughmeshesarenot

thepreferredtypeofgeometrytoworkwithinFreeCAD,becauseoftheirlackof

precisionandsupportforcurves,meshesstillhavealotofuses,andarefullysupported

inFreeCAD.TheMeshWorkbenchalsooffersanumberofPart-to-MeshandMesh-to-

Parttools.

TheRaytracingWorkbenchofferstoolstointerfacewithexternalrendererssuchas

povrayorluxrender.RightfrominsideFreeCAD,thisworkbenchallowsyoutoproduce

high-qualityrenderingsfromyourmodels.

TheSpreadsheetWorkbenchpermitsthecreationandmanipulationofspreadsheet

data,thatcanbeextractedfromFreeCADmodels.Spreadsheetcellscanalsobe

referencedinmanyareasofFreeCAD,allowingtousethemasmasterdatastructures.

TheFEMWorkbenchdealswithFiniteElementsAnalysis,andpermitstheperformingof

pre-andpost-processingFEMcalculationsandtodisplaytheresultsgraphically.

Externalworkbenches

Allworkbenchesataglance

A number of other very useful workbenches produced by FreeCAD community members

alsoexist.AlthoughtheyarenotincludedinastandardFreeCADinstallation,theyareeasy

toinstallasplug-ins.TheyareallreferencedintheFreeCAD-addonsrepository.Amongthe

mostdevelopedare:

TheDrawingDimensioningWorkbenchoffersmanynewtoolstoworkdirectlyon

DrawingSheetsandallowyoutoadddimensions,annotationsandothertechnical

symbolswithgreatcontrolovertheiraspect.

TheFastenersWorkbenchoffersawiderangeofready-to-insertfastenersobjectslike

screws,bolts,rods,washersandnuts.Manyoptionsandsettingsareavailable.

TheAssembly2Workbenchoffersaseriesoftoolstomountandworkwithassemblies.

Readmore

Thecompletelistofworkbenches:http://www.freecadweb.org/wiki/index.php?

title=Workbenches

ThePartWorkbench:http://www.freecadweb.org/wiki/index.php?title=Part_Module

TheDraftWorkbench:http://www.freecadweb.org/wiki/index.php?title=Draft_Module

TheSketcherandPartDesignWorkbench:http://www.freecadweb.org/wiki/index.php?

title=PartDesign_Workbench

TheArchWorkbench:http://www.freecadweb.org/wiki/index.php?title=Arch_Module

TheDrawingWorkbench:http://www.freecadweb.org/wiki/index.php?

title=Drawing_Module

TheFEMWorkbench:http://www.freecadweb.org/wiki/index.php?title=Fem_Workbench

TheFreeCAD-addonsrepository:https://github.com/FreeCAD/FreeCAD-addons

Allworkbenchesataglance

Traditionalmodeling-theCSGway

CGSstandsforConstructiveSolidGeometryanddescribesthemostbasicwaytoworkwith

solid3Dgeometry,whichiscreatingcomplexobjectsbyaddingandremovingpiecesto/from

solidsbyusingBooleanoperationssuchasunion,subtractionorintersection.

As we saw earlier in this manual, FreeCAD can handle many types of geometry, but the

preferred and most useful type for the kind of 3D objects that we want to design with

FreeCAD, that is, real-world objects, is, without a doubt, solid, BREP geometry, that is

mainly handled by the Part Workbench. Unlike polygon meshes, which are made only of

pointsandtriangles,BREPobjectshavetheirfacesdefinedbymathematicalcurves,which

permitsaboluteprecision,nomatterthescale.

The difference between the two can be compared to the difference between bitmap and

vectorial images. As with bitmap images, polygon meshes have their curved surfaces

fractionnedinaseriesofpoints.Ifyoulookatitfromveryclose,orprintitverylarge,youwill

seenotacurvedbutafacetedsurface.InbothvectorialimagesandBREPdata,theposition

of any point on a curve is not stored in the geometry but calculated on the fly, with exact

precision.

In FreeCAD, all BREP-based geometry is handled by another piece of open-source

software, OpenCasCade. The main interface between FreeCAD and the OpenCasCade

kernelisthePartWorkbench.Mostotherworkbenchesbuildtheirfunctionalityontopofthe

PartWorkbench.

Traditionalmodeling,theCSGway

Although other workbenches often offer more advanced tools to build and manipulate

geometry,sincetheyallactuallymanipulatePartobjects,itisveryusefultoknowhowthese

objectsworkinternally,andbeabletousetheParttoolssince,beingmoresimple,theycan

very often help you to work around problems that the more intelligent tools fail to solve

properly.

To illustrate the working of the Part Workbench, we will model this table, using only CSG

operations(exceptthescrews,forwhichwewilluseoneoftheaddons,andthedimensions,

whichwillseeinthenextchapter):

Let'screate anew document(Ctrl+N or menu File -> New Document), switch to the Part

Workbench,andbeginwiththefirstfoot:

Pressthe Boxbutton

Selectthebox,thensetthefollowingproperties(intheDatatab):

Length:80mm(or8cm,or0.8m,FreeCADworksinanyunit)

Width:80mm

Height:75cm

DuplicatetheboxbypressingCtrl+CthenCtrl+V(ormenuEdit->CopyandPaste)

Selectthenewobjectthathasbeencreated

Traditionalmodeling,theCSGway

ChangeitspositionbyeditingitsPlacementproperty:

Positionx:8mm

Positiony:8mm

Youshouldobtaintwohighboxes,one8mmapartfromtheother:

Nowwecansubtractonefromtheother:Selectthefirstone,thatis,theonethatwill

stay,then,withtheCTRLkeypressed,selecttheotherone,thatwillbesubtracted

(theorderisimportant)andpressthe Cutbutton:

Traditionalmodeling,theCSGway

Observethatthenewlycreatedobject,called"Cut",stillcontainsthetwocubesweusedas

operands. In fact, the two cubes are still there in the document, they have merely been

hidden and grouped under the Cut object in the tree view. You can still select them by

expandingthearrownexttotheCutobject,and,ifyouwish,turnthemvisibleagainbyright-

clickigthemorchangeanyoftheirproperties.

Nowlet'screatethethreeotherfeetbyduplicatingourbasecube6othertimes.Sinceit

isstillcopied,youcansimplypaste(Ctrl+V)6times.Changetheirpositionasfollows:

cube002:x:0,y:80cm

cube003:x:8mm,y:79.2cm

cube004:x:120cm,y:0

cube005:x:119.2cm,y:8mm

cube006:x:120cm,y:80cm

cube007:x:119.2cm,y:79.2cm

Nowlet'sdothethreeothercuts,selectingfirstthe"host"cubethenthecubetobecut

off.WenowhavefourCutobjects:

Traditionalmodeling,theCSGway

Youmighthavebeenthinkingthat,insteadofduplicatingthebasecubesixtimes,wecould

have duplicated the complete foot three times. This is totally true, as always in FreeCAD,

there are many ways to achieve a same result. This is a precious thing to remember,

because,aswewilladvanceintomorecomplexobjects,someoperationsmightnotgivethe

correctresultandweoftenneedtotryotherways.

Wewillnowmakeholesforthescrews,usingthesameCutmethod.Sinceweneed8

holes,twoineachfoot,wecouldmake8objectstobesubtracted.Instead,let'sexplore

otherwaysandmake4tubes,thatwillbereusedbytwoofthefeet.Solet'screatefour

tubesbyusingthe Cylindertool.Youcanagain,makeonlyoneandduplicateit

afterwards.Giveallcylindersaradiusof6mm.Thistime,wewillneedtorotatethem,

whichisalsodoneviathePlacementproperty:

cylinder:height:130cm,angle:90°,axis:x:0,y:1,position:x:-10mm,y:40mm,

z:72cm

cylinder001:height:130cm,angle:90°,axis:x:0,y:1,position:x:-10mm,y:84cm,

z:72cm

cylinder002:height:90cm,angle:90°,axis:x:-1,y:0,position:x:40mm,y:-10mm,

z:70cm

Traditionalmodeling,theCSGway

cylinder003:height:90cm,angle:90°,axis:x:-1,y:0,position:x:124cm,y:-10mm,

z:70cm

You will notice that the cylinders are a bit longer than needed. This is because, as in all

solid-based3Dapplications,booleanoperationsinFreeCADaresometimesoversensitiveto

face-on-facesituationsandmightfail.Bydoingthis,weputourselvesonthesafeside.

Nowlet'sdothesubtractions.Selectthefirstfoot,then,withCTRLpressed,selectone

ofthetubesthatcrossesit,presstheCutbutton.Theholewillbedone,andthetube

hidden.Finditinthetreeviewbyexpandingthepiercedfoot.

Selectanotherfootpiercedbythishiddentube,thenrepeattheoperation,thistime

Ctrl+selectingthetubeinthetreeview,asitishiddeninthe3Dview(youcanalso

makeitvisibleagainandselectitinthe3Dview).Repeatthisfortheotherfeetuntil

eachofthemhasitstwoholes:

Traditionalmodeling,theCSGway

As you can see, each foot has become a quite long series of operations. All this stays

parametric,andyoucangochangeanyparameterofanyoftheolderoperationsanytime.In

FreeCAD, we often refer to this pile as "modeling history", since it in fact carries all the

historyoftheoperationsyoudid.

Another particularity of FreeCAD is that the concept of 3D object and the concept of 3D

operationtendtoblendintoonesamething.TheCutisatthesametimeanoperation,and

the3Dobjectresultingfromthisoperation.InFreeCADthisiscalleda"feature",ratherthan

objectoroperation.

Nowlet'sdothetabletop,itwillbeasimpleblockofwood,let'sdoitwithanotherBox

withlength:126cm,width:86cm,height:8cm,position:x:10mm,y:10mm,z,67cm.In

theViewtab,youcangiveitanicebrownish,wood-likecolorbychangingitsShape

Colorproperty:

Traditionalmodeling,theCSGway

Notice that, although the legs are 8mm thick, we placed it 10mm away, leaving 2mm

betweenthem.Thisisnotnecessary,ofcourse,itwon'thappenwiththerealtable,butitisa

common thing to do in that kind of "assembled" models, it helps people who look at the

modeltounderstandthattheseareindependentparts,thatwillneedtobeattachedtogether

manuallylater.

Nowthat ourfive pieces arecomplete, itis a goodtime togive themmore proper names

than"Cut015".Byright-clickingtheobjectsinthetreeview(orpressingF2),youcanrename

themtosomethingmoremeaningfultoyourselfortoanotherpersonwhowouldopenyour

file later. It is often said that simlpy giving proper names to your objects is much more

importantthanthewayyoumodelthem.

Wewillnowplacesomescrews.Thereisnowadaysanextremelyusefuladdon

developedbyamemberoftheFreeCADcommunity,thatyoucanfindontheFreeCAD

addonsrepository,calledFasteners,thatmakestheinsertionofscrewsveryeasy.

Installingadditionalworkbenchesiseasyanddescribedontheaddonspages.

OnceyouhaveinstalledtheFastenersWorkbenchandrestartedFreeCAD,itwill

appearintheworkbencheslist,andwecanswitchtoit.Addingascrewtooneofour

holesisdonebyfirstselectingthecircularedgeofourhole:

Traditionalmodeling,theCSGway

ThenwecanpressoneofthescrewbuttonsoftheFastenersWorkbench,forexample

theEN1665Hexagonboltwithflanges,heavyseries.Thescrewwillbeplacedand

alignedwithourhole,andthediameterwillautomaticallybeselectedtomatchthesize

ofourhole.Sometimesthescrewwillbeplacedinverted,whichwecancorrectby

flippingitsinvertproprty.Wecanalsosetitsoffsetto2mm,tofollowthesamerulewe

usedbetweenthetabletopandthefeet:

Traditionalmodeling,theCSGway

Repeatthisforalltheholes,andourtableiscomplete!

TheinternalstructureofPartobjects

Aswesawabove,itispossibleinFreeCADtoselectnotonlywholeobjects,butpartsfor

them,suchasthecircularborderofourscrewhole.Thisisagoodtimetohaveaquicklook

at how Part objects are constructed internally. Every workbench that produces Part

geometrywillbebasedonthese:

Vertices:Thesearepoints(usuallyendpoints)onwhichalltherestisbuilt.For

example,alinehastwovertices.

Edges:theedgesarelineargeometrylikelines,arcs,ellipsesorNURBScurves.They

usuallyhavetwovertices,butsomespecialcaseshaveonlyone(aclosedcirclefor

example).

Wires:Awireisasequenceofedgesconnectedbytheirendpoints.Itcancontain

edgesofanytype,anditcanbeclosedornot.

Faces:Facescanbeplanarorcurved,andcanbeformedbyoneclosedwire,which

formstheborderoftheface,ormorethanone,incasethefacehasholes.

Shells:Shellsaresimplyagroupoffacesconnectedbytheiredges.Itcanbeopenor

Traditionalmodeling,theCSGway

closed.

Solids:Whenashellistighlyclosed,thatis,ithasno"leak",itbecomesasolid.Solids

carrythenotionofinsideandoutside.Manyworkbenchrelyonthistomakesurethe

objectstheyproducecanbebuiltintherealworld.

Compounds:Compoundsaresimplyaggegatesofothershapes,nomattertheirtype,

intoasingleshape.

Inthe3Dview,youcanselectindividualvertices,edgesorfaces.Selectingoneofthese

alsoselectsthewholeobject.

Anoteaboutshareddesign

Youmightlookatthetableabove,andthinkitsdesignisnotgood.Thetighteningofthefeet

withthetabletopisprobablytooweak.Youmightwanttoaddreforcingpieces,orsimplyyou

have other ideas to make it better. This is where sharing becomes interesting. You can

download the file made during this exercise from the link below, and modify it to make it

better.Then,ifyousharethatimprovedfile,othersmightbeabletomakeitevenbetter,or

use your well-designed table in their projects. Your design might then give other ideas to

otherpeople,andmaybeyouwillhavehelpedatinybittomakeabetterworld...

Downloads

Thefileproducedinthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/table.FCStd

Readmore

ThePartWorkbench:http://www.freecadweb.org/wiki/index.php?title=Part_Module

TheFreeCADaddonsrepository:https://github.com/FreeCAD/FreeCAD-addons

TheFastenersWorkbench:https://github.com/shaise/FreeCAD_FastenersWB

Traditionalmodeling,theCSGway

Traditional2Ddrafting

You might be interested by FreeCAD because you already have some technical drawing

experience,forexamplewithsoftwarelikeAutoCAD.Oryoualreadyknowsomethingabout

design,oryouprefertodrawthingsbeforebuildingthem.Ineithercases,FreeCADfeatures

a more traditional workbench, with tools found in most 2D CAD applications: The Draft

Workbench.

TheDraftWorkbench,althoughitadopts waysofworking inheritedfromthetraditional 2D

CADworld,isnotlimitedatalltothe2Drealm.Allitstoolsworkinthewhole3Dspaceand

many of the Draft tools, for example  Move or  Rotate, are commonly used all over

FreeCAD because they are often more intuitive than changing placement parameters

manually.

AmongthetoolsofferedbytheDraftWorkbench,youwillfindtraditionaldrawingtoolslike

Line, Circle,or Wire(polyline),modificationtoolslike Move, Rotateor Offset,

a working plane/grid system that allows you to define precisely in which plane you are

working, and a complete snapping system that makes it very easy to draw and position

elementspreciselyinrelationtoeachother.

Toshowcase theworkingand possibilitiesof the DraftWorkbench,we will walkthrough a

simple exercise, the result of which will be this little drawing, showing the floor plan of a

smallhousethatcontainsonlyakitchentop(Aprettyabsurdfloorplan,butwecandowhat

wewanthere,can'twe?):

Traditional2Ddrafting

SwitchtotheDraftWorkbench

Asinalltechnicaldrawingapplications,itiswisetosetupyourenvironmentcorrectly,it

willsaveyoualotoftime.Configurethegridandworkingplane,textanddimensions

settingstoyourlikingsinmenuEdit->Preferences->Draft.Inthisexercise,however,

wewillactasifthesepreferencesettingswerelefttotheirdefaultvalues.

Traditional2Ddrafting

TheDraftWorkbenchalsohastwospecialtoolbars:Onewithvisualsettings,where

youcanchangethecurrentworkingplane,turnconstructionmodeon/off,settheline

color,facecolor,lineweightandtextsizetobeusedfornewobjects,andanotherone

withsnaplocations.There,youcanturnthegridon/ofandset/unsetindividualSnap

locations:

Let'sstartbyturningconstructionmodeon,whichwillallowustodrawsome

guidelinesonwhichwewilldrawourfinalgeometry.

Ifyouwish,settheworkingplaneto*XY.Ifyoudothis,theworkingplanewon't

change,nomatterthecurrentview.Ifnot,theworkingplanewilladaptautomaticallyto

thecurrentview,andyoushouldtakecareofstayingintopviewwheneveryouwantto

drawontheXY(ground)plane.

Then,selectthe Rectangletoolanddrawarectangle,startingatpoint(0,0,0),of2

metersby2meters(leavetheZatzero).NotethatmostoftheDraftcommandscanbe

Traditional2Ddrafting

fullyperformedfromthekeyboard,withouttouchingthemouse,usingtheirtwo-letter

shortcut.Ourfirst2x2mrectanglecanbedonelikethis: re0Enter0Enter0

Enter2mEnter2mEnter0Enter.

Duplicatethatrectangleby15cminside,usingthe Offsettool,turningitsCopymode

on,andgivingitadistanceof15cm:

Wecanthendrawacoupleofverticallinestodefinewhereourdoorsandwindowswill

beplaced,usingthe Linetool.Thecrossingoftheselineswithourtworectangleswill

giveususefulintersectionstosnapourwallsto.Drawthefirstlinefrompoint(15cm,

1m,0)topoint(15cm,3m,0).

Duplicatethatline5times,usingthe MovetoolwithCopymodeturnedon.Turnalso

theRelativemodeon,whichwillallowustodefinemovementsinrelativedistances,

whichiseaierthancalculatetheexactpositionofeachline.Giveeachnewcopyany

startpoint,youcanleaveitat(0,0,0)forexample,andthefollowingrelativeendpoints:

line001:x:10cm

line002:x:120cm

line003:x:-55cm,y:-2m

line004:x:80cm

line005:x:15cm

Traditional2Ddrafting

Thatisallweneednow,sowecanswitchconstructionmodeoff.Checkthatallthe

constructiongeometryhasbeenplacedintoa"Construction"group,whichmakesit

easytohideitallatonceorevendeleteitcompletelylateron.

Nowlet'sdrawourtwowallpiecesusingthe Wiretool.Makesurethe intersection

snapisturnedon,aswewillneedtosnaptotheintersectionsofourlinesand

rectangles.Drawtwowiresasfollow,byclickingallthepointsoftheircontours.Toclose

them,eitherclickonthefirstpointagain,orpresstheClosebutton:

Traditional2Ddrafting

Wecanchangetheirdefaultgreycolortoanicehatchpattern,byselectingbothwalls,

thensettingtheirPatternpropertytoSimple,andtheirPatternsizetoyourliking,for

example0.005.

Traditional2Ddrafting

Wecannowhidetheconstructiongeometrybyright-clickingtheConstructiongroupand

chooseHideSelection.

Let'snowdrawthewindowsanddoors.Makesurethe midpointsnapisturnedon,

anddrawsixlinesasfollow:

Traditional2Ddrafting

Wewillnowchangethedoorlinetocreateanopeneddoorsymbol.Startbyrotatingthe

lineusingthe Rotatetool.Clicktheenpointofthelineasrotationcenter,giveita

startangleof0,andanendangleof-90.

Thencreatetheopeningarcwiththe Arctool.Pickthesamepointastherotation

centerweusedinthepreviousstepascenter,clicktheotherpointofthelinetogivethe

radius,thenthestartandendpointsasfollow:

Traditional2Ddrafting

Wecannowstartplacingsomefurniture.Tobeginwith,let'splaceacounterbydrawing

arectanglefromtheupperleftinnercorner,andgivingitawidthof170cmandaheight

of-60cm.Intheimagebelow,theTransparencypropertyoftherectangleissetto80%,

togiveitanicefurniturelook.

Thenlet'saddasinkandacooktop.Drawingthesekindsofsymbolsbyhandcanbe

verytedious,andtheyareusuallyeasytofindontheinternet,forexampleon

http://www.cad-blocks.net.IntheDownloadssectionbelow,forconvenience,we

separatedasinkandacooktopfromthissite,andsavedthemasDXFfiles.Youcan

downloadthesetwofilesbyvisitingthelinksbelow,andright-clickingtheRawbutton,

thenchoosingsaveas.

InsertingaDXFfileintoanopenedFreeCADdocumentcanbedoneeitherbychoosing

theFile->Importmenuoption,orbydragginganddroppingtheDXFfilefromyourfile

explorerintotheFreeCADwindow.ThecontentsoftheDXFfilesmightnotappearright

onthecenterofyourcurrentview,dependingonwheretheywereintheDXFfile.You

canusemenuView->Standardviews->Fitalltozoomoutandfindtheimported

objects.InsertthetwoDXFfiles,andmovethemtoasuitablelocationonthetabletop:

Traditional2Ddrafting

Wecannowplaceacoupleofdimensionsusingthe Dimensiontool.Dimensionsare

drawnbyclicking3points:thestartpoint,anendpoint,andathirdpointtoplacethe

dimensionline.Tomakehorizontalorverticaldimensions,evenifthetwofirstpointsare

notaligned,pressShiftwhileclickingthesecondpoint.

Youcanchangethepositionofadimensiontextbydouble-clickingthedimensioninthe

treeview.Acontrolpointwillallowyoutomovethetextgraphically.Inourexercise,the

"0.15"textshavebeenmovedawayforbetterclarity.

YoucanchangethecontentsofthedimensiontextbyeditingtheirOverrideproperty.In

ourexample,thetextsofthedoorandwindowsdimensionshavebeeneditedto

indicatetheirheights:

Traditional2Ddrafting

Let'saddsomedescriptiontextsusingthe Texttool.Clickapointtopositionthetext,

thenenterthelinesoftext,pressingEnteraftereachline.Tofinish,pressEntertwice.

Theindicationlines(alsocalled"leaders")thatlinkthetextstotheitemtheyare

describingaresimplydonewiththeWiretool.Drawwires,startingfromthetext

position,totheplacebeingdescribed.Oncethatisdone,youcanaddabulletorarrow

attheendofthewiresbysettingtheirEndArrowpropertytoTrue

Traditional2Ddrafting

Ourdrawingisnowcomplete!Sincetherebeginstobequiteanumberofobjectsthere,

itwouldbewisedosomecleaningandplaceeverythinginanicestructureofgroups,to

makethefileeasiertounderstandtoanotherperson:

Traditional2Ddrafting

WecannowprintourworkbyplacingitonaDrawingsheet,whichwewillshowfurther

inthismanual,ordirectlyexportourdrawingtootherCADapplications,byexportingit

toaDXFfile.Simplyselectour"Floorplan"group,selectmenuFile->Export,and

selecttheAutodeskDXFformat.Thefilecanthenbeopenedinanyother2DCAD

applicationsuchasLibreCAD.Youmightnoticesomedifferences,dependingonthe

configurationsofeachapplication.

Traditional2Ddrafting

ThemostimportantthingabouttheDraftWorkbench,however,isthatthegeometryyou

createwithitcanbeusedasabaseoreasilyextrudedinto3Dobjects,simplybyusing

the ExtrudetoolfromthePartWorkbench,or,tostayinDraft,the Trimex

(Trim/Extend/Extrude)tool,whichunderthehoodperformsaPartExtrusion,butdoesit

"theDraftway",thatis,allowsyoutoindicateandsnaptheextrusionlengthgraphically.

Experimentextrudingourwallsasshownbelow.

Bypressingthe workingplanebuttonafterselectingafaceofanobject,youarealso

abletoplacetheworkingplaneanywhere,andthereforedrawDraftobjectsindifferent

planes,forexampleontopofthewalls.Thesecanthenbeextrudedtoformother3D

solids.Experimentsettingtheworkingplaneononeofthetopfacesofthewalls,then

drawsomerectanglesupthere.

Traditional2Ddrafting

AllkindsofopeningscanalsobedoneaseasilybydrawingDraftobjectsonthefaces

ofwalls,thenextrudingthem,thenusingthebooleantoolsfromthePartWorkbenchto

subtractthemfromanothersolid,aswesawinthepreviouschapter.

Fundamentally, what the Draft Workbench does is provide graphical ways to create basic

Part operations. While in Part you will usually position objects by setting their placement

propertybyhand,inDraftyoucandoiton-screen.Therearetimeswhenoneisbetter,other

times when the other is preferable. Don't forget, you can create custom toolars in one of

theseworkbenches,addthetoolsfromtheother,andgetthebestofbothworlds.

Downloads

Thefilecreatedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/cabin.FCStd

ThesinkDXFfile:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/sink.dxf

ThecooktopDXFfile:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/cooktop.dxf

ThefinalDXFfileproducedduringthisexercise:

https://github.com/yorikvanhavre/FreeCAD-manual/blob/master/files/cabin.dxf

Readmore

Traditional2Ddrafting

TheDraftWorkbench:http://www.freecadweb.org/wiki/index.php?title=Draft_Module

Snapping:http://www.freecadweb.org/wiki/index.php?title=Draft_Snap

TheDraftworkingplane:http://www.freecadweb.org/wiki/index.php?

title=Draft_SelectPlane

Traditional2Ddrafting

Modelingforproductdesign

Productdesignisoriginallyacomercialterm,butinthe3Dworld,itoftenmeansmodeling

something with the idea to have it 3D-printed or, more generally, manufactured by a

machine,beinga3DprinteroraCNCmachine.

Whenyouprintobjectsin3D,itisofultimateimportancethatyourobjectsaresolid.Asthey

will become real, solid objects, this is obvious. Nothing prevent them from being hollow

inside, of course. But you always need to have a clear notion of which point is inside the

material,andwhichpointisoutside,becausethe3DprinterortheCNCmachineneedsto

knowexactlywhatisfilledwithmaterialandwhatisnot.For thisreason,inFreeCAD,the

PartDesignWorkbenchistheperfecttooltobuildsuchpieces,becauseitwillalwaystake

careforyouthatyourobjectsstaysolidandbuildable.

To illustrate how the PartDesign Workbench works, let's model this well-known piece of

Lego:

ThecoolthingwithLegopiecesisthatthedimensionsareeasytoobtainontheinternet,at

leastforthestandardpieces.Theseareprettyeasytomodelandprintona3Dprinter,and

withabitofpatience(3Dprintingoftenrequiresmuchadjustmentandfine-tuning)youcan

make pieces that are totally compatible and click perfectly into original Lego blocks.In the

examplebelow,wewillmakeapiecethatis1.5timesbiggerthantheoriginal.

Modelingforproductdesign

WewillnowuseexclusivelytheSketcherandPartDesigntools.Sinceallthetoolsfromthe

SketcherWorkbencharealsoincludedinthePartDesignWorkbench,wecanstayinPart

Designandwewillnotneedtoswitchbackandforthbetweenthetwo.

PartDesignobjects arefullybased onSketches.A Sketchisa2D object,madeoflinear

segments(lines,arcsofcircleorellipses)andconstraints.Theseconstraintscanbeapplied

eitheronlinearsegmentsorontheirendpointsorcenterpoints,andwillforcethegeometry

toadoptcertainrules.Forexample,youcanplaceaverticalconstraintonalinesegmentto

forceittostayvertical,oraposition(lock)constraintonanendpointtoprohibitittomove.

Whenasketchhasanexactamountofconstraintsthatprohibitsanypointofthesketchto

be moved anymore, we talk about a fully constrained sketch. when there are redundant

constraints,thatcould beremovedwithout allowingthegeometry tobemoved, itiscalled

over-constrained.Thisshouldbeavoided,andFreeCADwillnotifyyouifsuchcaseoccurs.

Sketcheshaveaneditmode,wheretheirgeometryandconstraintscanbechanged.When

youaredonewithediting,andleaveeditmode,sketchesbehaveslikeanyotherFreeCAD

object, and can be used as building blocks for all the Part Design tools, but also in other

workbenches,suchasPartorArch.TheDraftWorkbenchalsohasatoolthatconvertsDraft

objectstoSketches,andvice-versa.

Let'sstartbymodelingacubicshapethatwillbethebaseofourLegobrick.Lateron

wewillcarvetheinsides,andaddthe8dotsontopofit.Solet'sstartthisbymakinga

rectangularsketchthatwewillthenextrude:

SwitchtothePartDesignWorkbench

Clickonthe NewSketchbutton.Adialogwillappearaskingwhereyouwanttoliethe

sketch,choosetheXYplane,whichisthe"ground"plane.Thesketchwillbecreated

andwillimmediatelybeswitchedtoeditmode,andtheviewwillberotatedtolookat

yoursketchorthogonally.

Nowwecandrawarectangle,byselectingthe Rectangletoolandclicking2corner

points.Youcanplacethetwopointsanywhere,sincetheircorrectlocationwillbesetin

thenextstep.

Youwillnoticethatacoupleofconstraintshaveautomaticallybeenaddedtoour

rectangle:theverticalsegmentshavereceivedaverticalconstraint,thehorizontalones

ahorizontalconstraint,andeachcornerapoint-on-pointconstraintthatgluesthe

segmentstogether.Youcanexperimentmovingtherectanglearoundbydraggingits

lineswiththemouse,allthegeometrywillkeepobeyingtheconstraints.

Modelingforproductdesign

Now,let'saddthreemoreconstraints:

Selectoneoftheverticalsegmentsandadda VecticalDistanceConstraint.Give

itasizeof23.7mm.

Selectoneofthehorizontalsegmentsandadda HorizontalDistanceConstraint.

Makeit47.7mm.

Finally,selectoneofthecornerpoints,thentheoriginpoint(whichisthedotatthe

crossingoftheredandgreenaxes),thenadda Point-on-PointConstraint.The

rectanglewillthenjumptotheoriginpoint,andyoursketchwillturngreen,meaning

itisnowfullyconstrained.Youcantrymovingitslinesorpoints,nothingwillmove

anymore.

Modelingforproductdesign

Note that the last point-on-point constraint was not absolutely necessary. You are never

forcedtoworkwithfullyconstrainedsketches.However,ifwearegoingtoprintthisblockin

3D, it will be necessary to maintain our piece close to the origin point (which will be the

center of the space where the printer head can move). By adding that constraint we are

makingsurethatourpiecewillalwaysstay"anchored"tothatoriginpoint.

Ourbasesketchisnowready,wecanleaveeditmodebypressingtheClosebuttonon

topofitstaskpanel,orsimplybypressingtheEscapekey.Ifneededlateron,wecan

reentereditmodeanytimebydouble-clickingthesketchinthetreeview.

Let'sextrudeitbyusingthe Padtool,andgivingitadistanceof14.4mm.Theother

optionscanbeleftattheirdefaultvalues:

Modelingforproductdesign

ThePadbehavesverymuchlikethePartExtrudetoolthatweusedinthepreviouschapter.

Thereareacoupleofdifferences,though,themainonebeingthatapadcannotbemoved.

Itisattachedforevertoitssketch.Ifyouwanttochangethepositionofthepad,youmust

movethebasesketch.Inthecurrentcontext,wherewewanttobesurenothingwillmove

outofposition,thisisanadditionalsecurity.

Wewillnowcarvetheinsideoftheblock,usingthe Pockettool,whichisthe

PartDesignversionofPartCut.Tomakeapocket,wewillcreateasketchonthebottom

faceofourblock,whichwillbeusedtoremoveapartoftheblock.

Withthebottomfaceselected,pressthe NewSketchbutton.

Drawarectangleontheface.

Modelingforproductdesign

Wewillnowconstraintherectangleinrelationtothebottomface.Todothis,weneedto

"import"someedgesofthefacewiththe Externalgeometrytool.Usethistoolonthe

twoverticallinesofthebottomface:

Youwillnoticethatonlyedgesfromthethebasefacecanbeaddedbythistool.Whenyou

createasketchwithafaceselected,arelationiscreatedbetweenthatfaceandthesketch,

which is important for further operations. You can always remap a sketch to another face

Modelingforproductdesign

laterwiththe MapSketchtool.

Theexternalgeometryisnot"real",itwillbehiddenwhenweleaveeditmode.Butwe

canuseittoplaceconstraints.Placethe4followingconstraints:

Selectthetwoupperleftpointsoftherectangleandtheleftimportedlineandadda

HorizontalDistanceConstraintof1.8mm

Selectagainthetwoupperleftpointsoftherectangleandtheleftimportedlineand

adda VecticalDistanceConstraintof1.8mm

Selectthetwolowerrightpointsoftherectangleandtherightimportedlineand

adda HorizontalDistanceConstraintof1.8mm

Selectagainthetwolowerrightpointsoftherectangleandtherightimportedline

andadda VecticalDistanceConstraintof1.8mm

Leaveeditmodeandwecannowperformthepocketoperation:Withthesketch

selected,pressthe Pocketbuttton.Giveitalengthof12.6mm,whichwillleavethe

upperfaceofourpadwithathicknessof1.8mm(remember,thetotalheightofourpad

was14.4mm).

Modelingforproductdesign

Wewillnowattackthe8dotsonthetopface.Todothis,sincetheyarearepetitionofa

samefeature,wewillusethehandy LinearPatterntoolofthePartDesign

Workbench,whichallowstomodelonceandrepeattheshape.

Startbyselectingthetopfaceofourblock

Createa NewSketch.

Createtwo circles.

Adda RadiusConstraintof3.6mmtoeachofthem

Importtheleftedgeofthebasefacewiththe Externalgeometrytool.

Placetwoverticalconstraintsandtwohorizontalconstraintsof6mmbetweenthecenter

pointofeachcircleandthecornerpointsoftheimportededge,soeachcirclehasits

centerat6mmfromtheborderoftheface:

Modelingforproductdesign

Noticehow,onceagain,whenyoulockthepositionanddimensionofeverythinginyour

sketch,itbecomesfullyconstrained.Thisalwayskeepsyouonthesafeside.Youcould

changethefirstsketchnow,everythingwedidafterwardswouldkeeptight.

Leaveeditmode,selectthisnewsketch,andcreatea Padof2.7mm:

Noticethat,asearlierwiththepocket,sinceweusedthetopfaceofourbaseblockasa

baseforthislatestsketch,anyPartDesignoperationwedowiththissketchwillcorrectly

Modelingforproductdesign

bebuiltontopofthebaseshape:Thetwodotsarenotindependentobjects,theyhave

beenextrudeddirectlyfromourbrick.Thisisthegreatadvantageofworkingwiththe

PartDesignWorkbench,aslongasyoutakecareofalwaysbuildingonestepontopof

thepreviousone,youareactuallybuildingonefinalsolidobject.

Wecannowduplicateourtwodotsfourtimes,sowegeteight.SelectthelatestPadwe

justcreated.

Pressthe LinearPatternbutton.

Giveitalengthof36mm(whichisthetotal"span"wewantourcopiestofitin),inthe

"horizontalsketchaxis"direction,andmakeit4occurences:

Onceagain,seethatthisisnotjustaduplicationofanobject,itisafeatureofour

shapethathasbeenduplicated,thefinalobjectisstillonlyonesolidobject.

Nowlet'sworkonthethree"tubes"thatfillthevoidwecreatedonthebottomface.We

haveseveralpossibilities:createasketchwiththreecircles,paditthenpocketitthree

times,orcreateabasesketchwithonecircleinsidetheotherandpadittoformthe

completetubealready,orevenothercombinations.LikealwaysinFreeCAD,thereare

manywaystodoachieveasameresult.Sometimesonewaywillnotworkthewaywe

want,andwemusttryotherways.Here,wewilltakethesafestapproach,anddothings

onestepatatime.

Selectthefacethatisatthebottomofthehollowspacewecarvedearlierinsidethe

block.

Createanewsketch,addacirclewitharadiusof4.8825mm,importtheleftborderof

theface,andconstrainitverticallyandhorizontallyat10.2mmfromtheuppercornerof

theface:

Modelingforproductdesign

Leaveeditmode,andpadthissketchwithadistanceof12.6mm

Createalinearpatternfromthislastpad,giveitalengthof24mmand3occurences.

Wenowhavethreefilledtubesfillingthehollowspace:

Nowlet'smakethefinalholes.Selectthecircularfaceofthefirstofourthree"pins"

Createanewsketch,importthecircularboderofourface,createacirclewitharadius

constraintof3.6mm,andadda Point-on-PointConstraintbetweenthecenterofthe

Modelingforproductdesign

importedcircleandournewcircle.Wenowhaveaperfectlycenteredcircle,andonce

againfullyconstrained:

Leaveeditmode,andcreateapocketfromthissketch,withalengthof12.6mm

Createalinearpatternfromthispocket,withalengthof24mmand3occurences.

That'sthelaststep,ourpieceoflegoisnowcomplete,wecangiveitanicecolorof

Victory!

Modelingforproductdesign

Youwillnoticethatourmodelinghistory(whatappearsinthetreeview)hasbecomequite

long.Thisisofpreciousbecauseeverysinglestepofwhatwedidcanbechangedlateron.

Adaptingthismodelforanotherkindofbrick,forexampleonewith2x2dots,insteadof2x4,

would be a piece of cake, we would just need to change a couple of dimensions and the

numberofoccurencesinlinearpatterns.Wecouldaseasilycreatebiggerpiecesthatdon't

existintheoriginalLegogame.

Butwecouldalsoneedtogetridofthehistory,forexampleifwearegoingtomodelacastle

withthisbrick,andwedon'twanttohavethiswholehistoryrepeated500timesinourfile.

Therearetwosimplewaystogetridofthehistory,oneisusingtheCreatesimplecopytool

fromthePartWorkbench,whichwillcreateacopyofourpiecethatdoesn'tdependanymore

onthehistory(youcandeletethewholehistoryafterwards),theotherwayisexportingthe

pieceasaSTEPfileandreimportingit.

Assembling

Butthebestofbothworldsalsoexists,whichistheAssembly2Workbench,anaddonthat

can be installed from the FreeCAD-addons repository. This Workbench is named "2"

becausethereisalsoanofficialbuilt-inAssemblyWorkbenchindevelopment,whichisnot

ready yet. The Assembly2 Workbench, however, already works very well to construct

assemblies,andalsofeaturesacoupleofobject-to-objectconstraintswhichyoucanuseto

constrainthepositionofoneobjectinrelationtoanother.Intheexamplebelow,however,it

will be quicker and easier to position the pieces using  Draft Move and  Draft Rotate

thanusingtheAssembly2constraints.

Savethefilewediduntilnow

InstalltheAssembly2WorkbenchandrestartFreeCAD

Createanewemptydocument

SwitchtotheAssembly2workbench

PresstheImportapartfromanotherFreeCADdocumentbutton

Selectthefilewesavedabove

Thefinalpiecewillbeimportedinthecurrentdocument.TheAssembly2workbenchwill

determineautomaticallywhatisthefinalpieceinourfilethatneedstobeused,andthe

newobjectstayslinkedtothefile.Ifwegobackandmodifythecontentsofthefirstfile,

wecanpresstheUpdatepartsimportedintotheassemblybuttontoupdatethe

pieceshere.

ByusingtheImportapartfromanotherFreeCADdocumentbuttonseveraltimes,

andmovingandrotatingthepieces(withtheDrafttoolsorbymanipulatingtheir

Placementproperty),wecanquicklycreateasmallassembly:

Modelingforproductdesign

Downloads

Themodelproducedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/lego.FCStd

Readmore

TheSketcher:http://www.freecadweb.org/wiki/index.php?title=Sketcher_Module

ThePartDesignWorkbench:http://www.freecadweb.org/wiki/index.php?

title=PartDesign_Workbench

TheAssembly2Workbench:https://github.com/hamish2014/FreeCAD_assembly2

Modelingforproductdesign

Preparingmodelsfor3Dprinting

OneofthemainusesofFreeCADistoproducereal-worldobjects.Thesecanbedesigned

inFreeCAD,andthenmaderealbydifferentways,suchascommunicatedtootherpeople

whowillthenbuildthem,or,moreandmorefequently,sentdirectlytoa3DprinteroraCNC

mill.Thischapterwillshowyouhowtogetyourmodelsreadytosendtothesemachines.

Ifyouhavebeencautiouswhilemodeling,mostofthedifficultyyoumightencounterwhen

printingyourmodelin3Dhasalreadybeenavoided.Thisinvolvesbasically:

Makingsurethatyour3Dobjectsaresolid.Real-worldobjectsaresolid,the3Dmodel

mustbesolidtoo.WesawinearlierchaptersthatFreeCADhelpsyoualotinthat

regard,andthatthePartDesignWorkbenchwillnotifyyouifyoudoanoperationthat

preventsyourmodeltostaysolid.ThePartWorkbenchalsocontainsa Check

Geometrytoolthatishandytocheckfurtherforpossibledefects.

Makingsureaboutthedimensionsofyourobjects.Onemillimeterwillbeone

millimeterinreal-life.Everydimensionmatters.

Controllingthedegradation.No3DprintingorCNCmillingsystemcantakeFreeCAD

filesdirectly.MostofthemwillonlyunderstandamachinelanguagecalledG-Code.G-

codehasdozensofdifferentdialects,eachmachineorvendorusuallyusingitsown.

TheconversiomofyourmodelsintoG-Codecanbeeasyandautomatic,butyoucan

alsodoitmanually,withtotalcontrolovertheoutput.Inanycase,somelossofquality

ofyourmodelwillunavoidablyoccurduringtheprocess.Whenprintingin3D,youmust

alwaysmakesurethislossofqualitystaysbelowyourminimalrequirements.

Below,wewillassumethatthefirsttwocriteriasaremet,andthatbynowyouareableto

produce solid objects with correct dimensions. We will now see how to address the third

point.

Exportingtoslicers

This is the technique most commonly used for 3D printing. The 3D object is exported to

anotherprogram(theslicer)whichwillgeneratetheG-codefromtheobject,byslicingitinto

thinlayers(hencethename),whichwillreproducethemovementsthatthe3Dprinterwilldo.

Sincemanyofthose printersarehome-built,thereareoften smalldifferencesfromoneto

the other. These programs usually offer advanced configuration possibilities that allow to

tailortheoutputexactlyfortheparticularitiesofyour3Dprinter.

Actual 3D printing, however, is a too vast subject for this manual. But we will see how to

exportandusetheseslicerstocheckthattheoutputiscorrect.

Preparingmodelsfor3Dprinting

Convertingobjectstomeshes

Noneoftheslicerswill,atthisdate,takedirectlysolidgeometryasweproduceinFreeCAD.

Sowewillneedtoconvertanyobjectwewantto3Dprintintoameshfirst,thattheslicer

canopen.Fortunately,convertingasolidtoamesh,isverystraightforward.Allweneedto

becarefulabout,isthatit isnowthatthedegradationwe mentionedabovewilloccur.We

needtocheckthatthedegradationstaysinsideacceptablelimits.

All the mesh handling, in FreeCAD, is done by another specific workbench, the Mesh

Workbench. This workbench contains, the tools that convert between Part and Mesh

objects,severalutilitiesmeanttoanalyzeandrepairmeshes.Althoughworkingwithmeshes

isnotthefocusofFreeCAD,whenworkingwith3Dmodeling,youoftenneedtodealwith

meshobjects,sincetheiruseisverywidespreadamongotherapplications.Thisworkbench

allowsyoutohandlethemfullyinFreeCAD.

Let'sconvertoneoftheobjectswemodelledinthepreviouschapters,suchasthelego

piece(whichcanbedownloadedfromtheendofthepreviouschapter).

OpentheFreeCADfilecontainingthelegopiece.

SwitchtotheMeshWorkbench

Selectthelegobrick

SelectmenuMeshes->CreateMeshfromShape

Ataskpanelwillopenwithseveraloptions.Someadditionalmeshingalgorithms

(MefistoorNetgen)mightnotbeavailable,dependingonhowyourversionofFreeCAD

wascompiled.TheStandardmeshingalgorithmwillalwaysbepresent.Itoffersless

possibilitiesthanthetwoothers,butistotallysufficientforsmallobjectsthatfitintothe

maximumprintsizeofa3Dprinter.

Preparingmodelsfor3Dprinting

SelecttheStandardmesher,andleavethedeviationvaluetothedefaultvalueof0.10.

PressOk.

Ameshobjectwillbecreated,exactlyontopofoursolidobject.Eitherhidethesolid,or

moveoneoftheobjectsapart,soyoucancompareboth.

ChangetheView->DisplayModepropertyofthenewmeshobjecttoFlatLines,in

ordertoseehowthetriangulationoccured.

Ifyouarenothappy,andthinkthattheresultistoocoarse,youcanrepeatthe

operation,loweringthedeviationvalue.Intheexamplebelow,theleftmeshusedthe

defaultvalueof0.10,whiletherightoneuses0.01:

Preparingmodelsfor3Dprinting

Inmostcases,though,thedefaultvalueswillgiveasatisfyingresult.

Wecannowexportourmeshtoameshformat,suchasSTL,whichiscurrentlythe

mostwidelyusedformatin3Dprinting,byusingmenuFile->Exportandchoosingthe

STLfileformat.

Ifyoudon'towna3Dprinter,itisusuallyveryeasytofindcommercialservicesthatwillprint

and send you the printed objects by mail. Among the famous ones are Shapeways and

Sculpteo,butyouwillalsousuallyfindmanyothersinyourowncity.Inallmajorcities,you

will also nowadays find Fab labs, which are workshops equipped with a range of 3D

manufacturing machines, almost always including at least one 3D printer. Fab labs are

usually community spaces, that will let you use their machines, for a fee or for free

dependingontheFablab,butalsoteachyouhowtousethem,andpromoteotheractivities

around3Dmanufacturing.

UsingSlic3r

Slic3risanapplicationthatconvertsSTLobjectsintoG-codethatcanbesentdirectlyto3D

printers.Like FreeCAD, itis free, open-sourceand runsonWindows, MacOS and Linux.

Correctlyconfiguratingthingsfor3Dprintingisacomplicatedprocess,whereyoumusthave

a good knowledge of your 3D printer, so it is not very useful to generate G-code before

actually going to print (your G-code file might not work well on another printer), but it is

usefulforusanyway,tocheckthatourSTLfilewillbeprintablewithoutproblems.

Preparingmodelsfor3Dprinting

This is our exported STL file opened in Slic3r. By using the preview tab, and moving the

right slider, we can visualize the path that the 3D printer head will follow to construct our

object.

UsingtheCuraaddon

Cura is another free and open-source slicer application for Windows, Mac and Linux,

maintainedbythe3DprintermakerUltimaker.SomeFreeCADusershavecreatedaCura

Workbench that uses cura internally. The Cura Workbench is available from the FreeCAD

addonsrepository.TousetheCuraWorkbench,youalsoneedtoinstallCuraitself,whichis

notincludedintheworkbench.

Onceyou haveinstalledboth Curaand theCura Workbench,youwill be ableto useit to

produce the G-code file directly from Part objects, without the need to convert them to

meshes, and without the need to open an external application. Producing another G-code

filefromourLegobrick,usingtheCuraWorkbenchthistime,isdoneasfollows:

LoadthefilecontainingourLegobrick(itcanbedownloadedattheendoftheprevious

chapter)

SwitchtotheCuraWorkbench

Setuptheprinterspacebychoosingmenu3Dprinting->Createa3Dprinter

definition.Sincewearen'tgoingtoprintforreal,wecanleavethesettingsastheyare.

Thegeometryoftheprintingbedandavailablespacewillbeshowninthe3Dview.

MovetheLegobricktoasuitablelocation,suchasthecenteroftheprintingbed.

Preparingmodelsfor3Dprinting

RememberthatPartDesignobjectscannotbemoveddirectly,soyouneedeitherto

moveitsveryfirstsketc(thefirstrectangle),ortomove(andprint)acopy,whichcanbe

madewiththePart->CreateSimpleCopytool.Thecopycanbemoved,forexample

with Draft->Move.

Selecttheobjecttobeprinted,andselectmenu3Dprinting->SlicewithCura

Engine.

Inthetaskpanelthatwillopen,makesurethepathtotheCuraexecutableiscorrectly

set.Sincewearenotgoingtoreallyprint,wecanleaveallotheroptionsastheyare.

PressOk.TwofileswillbegeneratedinthesamedirectoryasyourFreeCADfile,an

STLfileandaG-codefile.

ThegeneratedG-codecanalsobereimportedintoFreeCAD(usingtheslic3r

preprocessor)forchecking.

GeneratingG-code

FreeCADalsooffersmoreadvancedwaystogenerateG-codedirectly.Thisisoftenmuch

morecomplicatedthanusingautomatictoolsaswesawabove,buthastheadvantagetolet

youfullycontroltheoutput.Thisisusuallynotneededwhenusing3Dprinters,butbecomes

veryimportantwhendealingwithCNCmilling,asthemachinesaremuchmorecomplex.

G-codepathgenerationinFreeCADisdonewiththePathWorkbench.Itfeaturestoolsthat

generatefullmachinepathsandothersthatgenerateonlypartsofaG-codeproject,thatcan

beassembledtoformawholemillingoperation.

Preparingmodelsfor3Dprinting

GeneratingCNCmillingpathsisanothersubjectthatismuchtoovasttofitinthismanual,

sowearegoingtoshowhowtobuildasimplePathproject,withoutcaringmuchaboutmost

ofthedetailsofrealCNCmachining.

Loadthefilecontainingourlegopiece,andswitchtothePathWorkbench.

Sincethefinalpiecedoesn'tcontainanymorearectangulartopface,hidethefinallego

piece,andshowthefirstcubicpadthatwedid,whichhasarectangulartopface.

Selectthetopfaceandpressthe FaceProfilebutton.

SetitsOffsetpropertyto1mm.

Then,let'sduplicatethisfirstloopacoupleoftimes,sothetoolwillcarveoutthewhole

block.SelecttheFaceProfilepath,andpressthe Arraybutton.

SettheCopiespropertyofthearrayto8,anditsOffsetto-2mmintheZdirection,and

movetheplacementofthearrayby2mmintheZdirection,sothecuttingwillstartabit

abovethepad,andincludetheheightofthedotstoo.

Preparingmodelsfor3Dprinting

100

Nowwehavedefinedapaththat,whenfollowedbythemillingmachine,willcarvea

rectangularvolumeoutofablockofmaterial.Wenowneedtocarveoutthespace

betweenthedots,inordertorevealthem.HidethePad,andshowthefinalpieceagain,

sowecanselectthefacethatliesbetweenthedots.

Selectthetopface,andpressthe FacePocketbutton.SettheOffsetpropertyto

1mm,andtheretractionheightto20mm.Thatistheheighttowherethecutterwill

travelwhenswitchingfromonelooptoanother.Otherwise,thecuttermightcutright

throughoneofourdots:

Preparingmodelsfor3Dprinting

101

Onceagain,makeanarray.SelecttheFacePocketobject,andpressthe Array

button.SettheCopiesnumberto1andtheoffsetto-2mmintheZdirection.Movethe

placementofthearrayby2mmintheZdirection.Ourtwooperationsarenowdone:

Nowallthatislefttodoistojointhesetwooperationsintoone.Thiscanbedonewitha

PathCompoundoraPathProject.Sincewewillneednothingmoreandwillbereadyto

exportalready,wewillusetheproject.Pressthe Projectbutton.

SettheUsePlacementspropertyoftheprojectistoTrue,becausewechangedthe

placementofthearrays,andwewantthattobetakenintoaccountintheproject.

Inthetreeview,draganddropthetwoarraysintotheproject.Youcanreorderthe

arraysinsidetheprojectifneeded,bydouble-clickingit.

Preparingmodelsfor3Dprinting

102

TheprojectcannowbeexportedtoG-code,byselectingit,choosingmenuFile->

Export,selectingtheG-codeformat,andinthepop-updialogthatwillopen,selectinga

post-procesingscriptaccordingtoyourmachine.

Therearemanyapplicationsavailabletosimulatetherealcutting,oneofthemthatisalso

multi-platformandopen-source,likeFreeCAD,isCamotics.

Downloads

TheSTLfilegeneratedinthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/lego.stl

Thefilegeneratedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/path.FCStd

TheG-codefilegeneratedinthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/lego.gcode

Readmore

TheMeshWorkbench:http://www.freecadweb.org/wiki/index.php?title=Mesh_Module

TheSTLfileformat:https://en.wikipedia.org/wiki/STL_%28file_format%29

Slic3r:http://slic3r.org/

Cura:https://ultimaker.com/en/products/cura-software

TheCuraWorkbench:https://github.com/cblt2l/FreeCAD-CuraEngine-Plugin

ThePathWorkbench:http://www.freecadweb.org/wiki/index.php?title=Path_Workbench

Camotics:http://camotics.org/

Preparingmodelsfor3Dprinting

103

Generating2Ddrawings

Whenyourmodelcannotbeprintedormilleddirectlybyamachine,forexampleitistoobig

(abuilding)oritrequiresmanualassemblyafterthepiecesareready,youwillusuallyneed

to explain to another person how to do that. In technical fields (engineering, architecture,

etc),thisisusuallydonewithdrawings,thatarehandedovertothepersonresponsiblefor

assemblingthefinalproduct,thatwillexplainhowtodoit.

TypicalexamplesareIkeainstructions,architecturaldrawingsorblueprints.Thesedrawings

usually contain not only the drawing itself, but also many annotations, such as texts,

dimensions,numbers,symbolsthatwillhelpother peopletounderstandwhatneedstobe

doneandhow.

In FreeCAD, the workbench responsible for making such drawings is the Drawing

Workbench.

TheDrawingWorkbenchallowsyoutocreatesheets,whichcanbeblankoruseapre-made

templatetoalreadyhaveaseriesofitemsonthesheet,suchasbordersandtitle.Onthese

sheets,youcanthenplaceviewsofthe3Dobjectsyoumodeledpreviously,andconfigure

how these views must appear on the sheet. Finally, thanks to an addon called Drawing

DimensioningWorkbench,youcanalsoplaceallkindsofannotationsonthesheet,suchas

dimensions,texts,andotherusualsymbolscommonlyusedintechnicaldrawings.

Drawingsheets,oncecomplete,canbeprintedorexportedasSVG,PDForDXFfiles.

Inthefollowingexercise,wewillseehowtocreateasimpledrawingofachairmodelfound

intheFreeCADlibrary(Furniture->Chairs->IkeaChair).TheFreeCADlibrarycaneasilybe

addedtoyourFreeCADinstallation(refertotheinstallingchapterofthismanual),oryoucan

simplydownloadthemodel fromthelibrarywebpage, orviathedirect linkprovidedatthe

bottomofthischapter.

Generating2Ddrawings

104

LoadtheIkeaChairfilefromthelibrary.Youcanchoosebetweenthe.FCStdversion,

whichwillloadthefullmodelinghistory,orthe.stepversion,whichwillcreateonlyone

object,withoutthehistory.Sincewewon'tneedtomodelanyfurthernow,itisbestto

Generating2Ddrawings

105

choosethe.stepversion,asitwillbeeasiertomanipulate.

SwitchtotheDrawingWorkbench

Pressthelittlearrownexttothe NewDrawingPagebutton.

SelecttheA4Portrait/ISO7200template.AnewtabwillopeninyourFreeCAD

window,showingthenewpage.

Inthetreeview(orinthemodeltab),selectthechairmodel.

Pressthe Insertviewbutton.

AViewobjectwillbecreatedonourpage.Givetheviewthefollowingproperties:

X:100

Y:150

Scale:0.1

Rotation:270

Wenowhaveanicetopview(whichisthedefaultprojection)ofourchair:

Generating2Ddrawings

106

Let'srepeattheoperationtwice,tocreatetwomoreviews.WewillsettheirXandY

values,whichindicatethepositionoftheviewonthepage,inordertoshowthemapart

fromthetopview,andtheirdirection,tocreatedifferentvieworientations.Giveeach

newviewthefollowingproperties:

View001(frontview):X:100,Y:130,Scale:0.1,Rotation:90,Direction:(-1,0,0)

View002(sideview):X:180,Y:130,Scale:0.1,Rotation:90,Direction:(0,-1,0)

Afterthat,weobtainthefollowingpage:

Generating2Ddrawings

107

Wecantweakabittheaspectofourviewsifwewant,forexamplewecanraisetheir

LineWidthpropertyto0.5.

Wewillnowplacedimensionsandindicationsonourdrawing.Therearetwowaysto add

dimensions to a model, one is placing the dimensions inside the 3D model, using the

DimensiontooloftheDraftWorkbench,andthenplaceaviewofthesedimensionsonour

sheet with the  Draft View tool (which can be used with a single dimension or a group

containing dimensions), or we can do things directly on the Drawing sheet, using the

DrawingDimensioningWorkbench,whichisinstallablefrom theFreeCADaddons. We will

useherethislattermethod.

SwitchtotheDrawingDimensioningWorkbench

PresstheAddLinearDimensionbutton.Availablenodesarehighlightedingreenon

thedrawingpage:

Generating2Ddrawings

108

Clicktwoofthesepoints,thenclickathirdpointtoplacethedimensionline:

TheLinearDimensiontool,asmostoftheotherDrawingDimensioningtools,willnot

exitafteryoufinished,allowingyoutoplacemoredimensions.Whenyouaredone,

simplyclicktheClosebuttonintheTaskpanel.

Repeattheoperation,untilallthedimensionsyouwishtoindicateareplaced.Takea

minutetobrowsethroughthedifferentoptionsproposedintheLinearDimension'stask

panel.Forexample,byuntickingtheautoplacetextoption,youwillbeabletoplace

thetextofthedimensionelsewhere,likeontheimagebelow:

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Wewillnowplacetwoindications,usingtheWelding/Groovesymbolstool,selecting

thedefaultone(nogroovesymbol).Drawthetwolineslikeontheimageabove.

NowplacetwotextsusingtheAddtexttool,andchangetheirtextpropertytothe

contentsofyourlikings.

Ourdrawingisnowcomplete,allthatislefttodoistofillintheinformationsofthesheet

titleblock.WithmostofthedefaultFreeCADtemplates,thiscanbedoneeasily,by

changingtheEditableTextspropertyofthepage.

Our page can now be exported to SVG to be worked further in graphical applications like

inkscape, or to DXF by selecting menu File -> Export. The Drawing Dimensioning

workbench also features its own DXF export tool, which also supports the annotations

added with that workbench. The DXF format is importable in almost all existing 2D CAD

applications.DrawingpagescanalsobedirectlyprintedorexportedtoPDF.

Downloads

Thechairmodel:https://github.com/FreeCAD/FreeCAD-

library/blob/master/Furniture/Chairs/IkeaLikeChair.step

Thefilecreatedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/drawing.FCStd

TheSVGsheetproducedfromthatfile:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/drawing.svg

Readmore

TheDrawingWorkbench:http://www.freecadweb.org/wiki/index.php?

title=Drawing_Module

TheDrawingDimensioningWorkbench:

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https://github.com/hamish2014/FreeCAD_drawing_dimensioning

TheFreeCADlibrary:https://github.com/FreeCAD/FreeCAD-library

Inkscape:http://www.inkscape.org

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BIMmodeling

BIMstandsforBuildingInformationModeling.Theexactdefinitionofwhatitisvaries,butwe

cansay simplythat ishow buildingsand otherlarge structureslike bridges,tunnels, etc...

aremodeledtoday.BIMmodelsareusuallybasedon3Dmodels,andalsoincludeaseries

of additional layers of information, such as materials information, relationships to other

objectsormodels,orspecialinstructionsforbuildingormaintenance.Thisextrainformation

permitsallkindsofadvancedanalysesofthemodel,suchasstructuralresistance,costand

constructiontimeestimations,orcalculaitonsofenergyconsumption.

The Arch Workbench of FreeCAD implements a series of tools and facilities for BIM

modeling.Althoughithasadifferentpurpose,itismadetoworkintightintegrationwiththe

rest of FreeCAD: Anything made with any other workbench of FreeCAD can become an

Archobject,orbeusedasabaseforanArchobject.

AsinthePartDesignWorkbench,theobjectsproducedbytheArchWorkbencharemeantto

bebuiltintherealworld.Therefore,theyneedtobesolid.TheArchtoolsusuallytakecare

ofthatautomatically,andalsoprovideutilitytoolstohelpyoucheckthevalidityofobjects.

TheArchWorkbenchalsoincludesallthetoolsfromtheDraftWorkbench,andusesitsgrid

and snapping system. Before beginning, it is always a good idea to browse through the

preferencespagesofbothDraftandArchandsetthedefaultsettingstoyourlikings.

Inthischapter,wewillseehowtomodelthissmallbuilding:

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112

andproduceaplanandasectionviewfromit:

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113

Createanewdocument,andswitchtotheArchWorkbench.

OpenmenuEdit->Preferences->Draft->GridandSnappingandsetthegrid

spacingsettingto1000mm,sowehaveaonemeter-basedgrid,whichwillbe

convenientforthesizeofourbuiding.

Onthesnappingtoolbar,makesurethe gridsnapbuttonisenabled,sowecanuse

thegridasmuchaspossible.

SettheWorkingPlanetoXYplane

Drawfourlineswiththe DraftLinetool.Youcanentercoordinatesmanually,or

simplypickthepointsonthegridwiththemouse:

Frompoint(0,0)topoint(0,3)

Frompoint(0,3)topoint(4,3)

Frompoint(4,3)topoint(4,0)

Frompoint(4,0)topoint(0,0)

Noticethatwedrewalwaysinthesamedirection(clockwise).Thisisnotnecessary,butwill

ensurethatthewallsthatwewillbuildnextallhavethesameleftandrightdirections.You

mightalso think wecouldsimply have drawna rectangle here,which is true.But the four

lineswillallowustoillustratebetterhowtoaddoneobjectintoanother.

Selectthefirstline,thenpressthe ArchWallbutton.

Repeatthisforthe3otherlines,untilyouhave4walls.

Selectthefourwalls,andsettheirHeightpropertyto3.00mandtheirAlignment

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propertytoleft.Ifyoudidn'tdrawthelinesinthesameorderaswedidabove,someof

thewallsmighthavetheirleftandrightdirectionsflipped,andmightneedtobesetto

rightinstead.Youwillobtainfourintersectingwalls,ontheinsideofthebaselines:

Nowweneedtojointhesewallstogether,sotheyintersectproperly.Thisisnotnecessary

whenyourwallsaredrawninawaythattheyalreadyconnectcleanly,buthereweneedto,

sincetheyareintersecting.InArch,thisisdonebyelectingoneofthewallstobethe"host",

andaddingtheotherstoit,as"additions".Allarchobjectscanhaveanynumberofadditions

(objects whose geometry will be added to the host's geometry), and subtractions (objects

whose geometry will be subtracted). The additions and subtractions of an object can be

managedanytimebydouble-clickingtheobjectinthetree.

SelectthefourwallswithCtrlpressed,thelastonebeingthewallthatyouchoseto

becomethehost

Pressthe ArchAddbutton.Thefourwallshavenowbeenturnedintoone:

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Theindividualwallsarehoweverstillaccessible,byexpandingthewallinthetreeview.

Let'snowplaceadoor.InFreeCAD,doorsareconsideredaspecialcaseofwindows,

sothisisdoneusingtheWindowtool.

Startbyselectingthewall.Thisisnotnecessary,butagoodhabittotake.Ifanobjectis

selectedwhenstartingthewindowtool,youwillforcethewindowtobeinsertedinthat

object,evenifyousnaptoanotherobject.

SettheWorkingPlanetoautosowearenotrestrictedtothegroundplane

Pressthe Windowbutton.

Inthewindowcreationpanel,selecttheSimpledoorpreset,andsetitsWidthto0.9m

anditsHeightto2.1m

Makesurethe Nearsnaplocationisturnedon,sowecansnaponfaces

Placeyourwindowroughlyonthemiddleofthefrontfaceofthewall:

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Afterclicking,ourwindowisplacedonthecorrectface,butnotexactlywherewewant:

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Wecannowsetthepreciselocationbyexpandingthewallandthewindowobjectsin

thetreeview,andchangingthePlacementpropertyofthebasesketchofourdoor.Set

itspositiontox=2m,y=0,z=0.Ourwindowisnowexactlywherewewantit:

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Repeattheoperationtoplaceawindow:Selectthewall,pressthewindowtool,select

theOpen2-panepreset,andplacea1mx1mwindowinthesamefaceasthedoor.

Settheplacementoftheunderlyingsketchtopositionx=0.6m,y=0,z=1.1m,sothe

upperlineofthewindowisalignedtothetopofthedoor.

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Windowsarealwaysbuiltonsketches.Itiseasytocreatecustomwindowsbyfirstcreating

asketchonaface,thenturningitintoa windowbyselectingit,thenpressingthewindow

button. Then, the window creation parameters, that is, which wires of the sketch must be

extrudedandhowmuch,canbedefinedbydouble-clickingthewindowinthetreeview.Let's

nowcreateaslab:

SettheWorkingPlanetoXYplane

Createa rectanglewithalengthof5m,aheightof4m,andplaceitatposition

x:-0.5m,y:-0.5m,z:0.

Selecttherectangle

Clickthe structuretooltocreateaslabfromtherectangle

Settheheightpropertyoftheslabto0.2manditsnormaldirectionto(0,0,-1)because

wewantittoextrudedownwards.Wecouldalsosimplyhavemovedit0.2mdown,butit

isalwaysgoodpracticetokeepextrudedobjectsatthesameplaceastheirbaseprofile.

SettheRolepropertyoftheslabtoslab.ThisisnotnecessaryinFreeCAD,butis

importantforIFCexport,asitwillensurethattheobjectisexportedwiththecorrectIFC

type.

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Let'snowuseoneofthestructuralpresetstomakeametallicbeam.Clickthe

structurebutton,selectaHEB180preset,andsetitsheightto4m.Placeitanywhere:

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Adjustitsplacementbysettingitsrotationto90°inthe(1,0,0)axis,anditspositionto

x:90mm,y:3.5m,z:3.09m.Thiswillpositionthebeamexactlyononeofthesidewalls:

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Weneednowtoduplicatethisbeamacoupleoftimes.Wecoulddothatonebyone

usingthe clonetool,butthereisabetterway,todoallthecopiesatonceusingan

array:

Selectthebeam

Pressthe Arraybutton

SettheNumberXpropertyofthearrayto6,leavetheYandZnumbersto1

ExpandtheintervalXproperty,andpressthesmall expressioniconattheright

sideoftheXfield.Thiswillopenanexpressionseditor:

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Write(4m-180mm)/5intheexpressionfield,andpressOK.Thiswillsetthexvalueto

0.764(4misthetotallengthofourfrontwall,180mmisthewidthofthebeam,whichis

whyitiscalledHEB180,andwewantafifthofthatspaceasintervalbetweeneach

beam):

Wecannoweasilybuildasimpleslabontopofthem,bydrawingarectangledirectlyon

thetopplaneofthebeams.Selectatopfaceofoneofthebeams

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Pressthe workingplanebutton.Theworkingplaneisnowsettothatface.

Createa rectangle,snappingtotwooppositepointsoftheborderbeams:

Selecttherectangle

Clickthe structurebuttonandcreateaslabwithaheightof0.2m.

That's it, our model is now complete. We should now organize it so it exports correctly to

IFC.TheIFCformatrequiresthatallobjectsofabuildingareinsideabuildingobject,and

optionally,insideastorey.Italsorequiresthatallbuildingsareplacedonasite,buttheIFC

exporterofFreeCADwilladdadefaultsiteautomaticallyifneeded,sowedon'tneedtoadd

onehere.

Selectthetwoslabs,thewall,andthearrayofbeams

Pressthe Floorbutton

Selectthefloorwejustcreated

Pressthe Buildingbutton

Ourmodelisnowreadytoexport:

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TheIFCformatisoneofthemostpreciousassetsinafreeBIMworld,becauseitallowsthe

exchangeofdata betweenanyapplication andactorof theconstructionworld, inanopen

manner(theformatisopen,freeandmaintainedbyanindependentconsortium).Exporting

your BIM models as IFC ensures that anyone can see and analyze them, no matter the

applicationused.

In FreeCAD, IFC import and export is done by interfacing with another piece of software,

called IfcOpenShell. To be able to export to IFC from FreeCAD, the IfcOpenShell-python

package must be installed on your system. Be sure to select one which uses the same

python version as FreeCAD. The python version that FreeCAD uses is informed when

openingtheView->Panels->PythonconsolepanelinFreeCAD.Whenthatisdone,we

cannowexportourmodel:

Selectthetopobjectyouwanttoexport,thatis,theBuildingobject.

SelectmenuFile->Export->IndustryFoundationClassesandsaveyourfile.

TheresultingIFCfilecannowbeopenedinawiderangeofapplicationsandviewers

(theimagebelowshowsthefileopenedinthefreeIfcPlusPlusviewer.Checkingthe

exportedfileinsuchaviewerapplicationbeforedistributingittootherpeopleis

importanttocheckthatallthedatacontainedinthefileiscorrect.FreeCADitselfcan

alsobeusedtore-opentheresultingIFCfile.

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We will now place some dimensions. Unlike the previous chapter, where we drew all the

dimensionsdirectlyontheDrawingsheet,wewilluseanothermethodhere,andplaceDraft

dimensionsdirectlyinthe3Dmodel.ThesedimensionswillthenbeplacedontheDrawing

sheet. We will first make two groups for our dimensions, one for the dimensions that will

appearintheplanview,andanotherforthosethatappearontheelevation.

Right-clickthe"house"documentinthetreeview,andcreatetwonewgroups:Plan

dimensionsandElevationdimensions.

SettheWorkingPlanetoXYplane

Makesurethe restrictsnaplocationisturnedon,soeverythingyoudrawstayson

theworkingplane.

Drawacoupleof dimensions,forexampleasontheimagebelow.PressingShift

andCtrlwhilesnappingthedimensionpointswillgiveyouadditionaloptions.

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Selectallyourdimensions,anddragthemtothePlandimensionsgroupinthetree

view

SettheWorkingPlanetoXZplane,thatis,thefrontalverticalplane.

Repeattheoperation,drawacoupleofdimensions,andplacethemintheElevation

dimensionsgroup.

Wewillnowprepareasetofviewsfromourmodel,tobepacedonaDrawingpage.Wecan

do that with the tools from the Drawing Workbench, as we have seen in the previous

chapter, but the Arch Workbench also offers an all-in-one advanced tool to produce plan,

section and elevation views, called Section Plane. We will now add two of these section

planes,tocreateaplanviewandanelevationview.

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Selectthebuildingobjectinthetreeview

Pressthe SectionPlanebutton.

SetitsDisplayHeightpropertyto5m,itsDisplayLengthto6m,soweencompassour

house(thisisnotneeded,butwilllookbetter,asitwillshownaturallywhatitisused

for),anditsPlacementpositionatx:2m,y:1.5m,z:1.5m.

CheckthelistofobjectsconsideredbytheSectionPlanebydouble-clickingitinthetree

view.SectionPlanesonlyrenderspecifiedobjectsfromthemodel,notallofthem.The

objectsconsideredbytheSectionPlanecanbechangedhere.

Repeattheoperationtocreateanothersectionplane,giveitthesamedisplaylength

andheight,andgiveitthefollowingPlacement:position:x:2m,y:-2m,z:1.5m,angle:

90°,axis:x:1,y:0,z:0.Makesurethisnewsectionplanealsoconsidersthebuilding

object.

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Nowwehaveeverythingweneed,andwecancreateourDrawingpage.Startby

switchingtotheDrawingWorkbench,andcreateanewdefault A3page(orselect

anothertemplateifyouwish).

Selectthefirstsectionplane,usedfortheplanview

Pressthe DraftViewbutton.Thistooloffersacoupleofadditionalfeaturesoverthe

standardDrawingViewtool,andsupportstheSectionPlanesfromtheArch

Workbench.

Givethenewviewthefollowingproperties:

X:50

Y:140

Scale:0.03

Linewidth:0.15

ShowCutTrue

ShowFill:True

Selecttheothersectionplane,andcreateanewDraftView,withthefollowng

properties:

X:250

Y:150

Scale:0.03

Rendering:Solid

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WewillnowcreatetwomoreDraftViews,oneforeachgroupofdimensions.

SelectthePlandimensionsgroup

Pressthe DraftViewbutton.

Givethenewviewthefollowingproperties:

X:50

Y:140

Scale:0.03

Linewidth:0.15

Fontsize:10mm

Repeattheoperationfortheothergroup,withthefollowingsettings:

X:250

Y:150

Scale:0.03

Linewidth:0.15

Fontsize:10mm

Direction:0,-1,0

Rotation:90°

Ourpageisnowready,andwecanexportittoSVGorDXFformats,orprintit.TheSVG

formatallowstoopenthefileillustrationapplicationssuchasinkscape,withwhichyoucan

quicklyenhancetechnicaldrawingsandturnthemintomuchnicerpresentationdrawings.It

offersmanymorepossibilitiesthantheDXFformat.

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Downloads

Thefileproducedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/house.FCStd

TheIFCfileexportedfromtheabovefile:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/house.ifc

TheSVGfileexportedfromtheabovefile:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/house.svg

Readmore

TheArchWorkbench:http://www.freecadweb.org/wiki/index.php?title=Arch_Module

TheDraftworkingplane:http://www.freecadweb.org/wiki/index.php?

title=Draft_SelectPlane

TheDraftsnappingsettings:http://www.freecadweb.org/wiki/index.php?title=Draft_Snap

Theexpressionssystem:http://www.freecadweb.org/wiki/index.php?title=Expressions

TheIFCformat:https://en.wikipedia.org/wiki/Industry_Foundation_Classes

IfcOpenShell:http://ifcopenshell.org/

IfcPlusPlus:http://ifcplusplus.com/

Inkscape:http://www.inkscape.org

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Usingspreadsheets

FreeCADfeatures another interestingworkbench to explore:the Spreadsheet Workbench.

ThisworkbenchallowstocreatespreadsheetssuchasthosemadewithExcelorLibreOffice

directly in FreeCAD. These spreadsheets can then be populated with data extracted from

your model, and can also perform a series of calculations between values. Spreadsheets

canbeexportedasCSVfiles,whichcanbeimportedinanyotherspreadsheetapplication.

In FreeCAD, however, spreadsheets have an additional utility: Their cells can receive a

name,andcanthenbereferencedbyanyfieldsupportedbytheexpressionsengine. This

turns spreadsheets into powerful control structures, where the values inserted in specific

cells can drive dimensions of the model. There is only one thing to keep in mind, as

FreeCADprohibitscirculardependenciesbetweenobjects,asamespreadsheetcannotbe

usedtosetapropertyofanobjectandatthesametimeretrieveapropertyvaluefromthe

sameobject.Thatwouldmakethespreadsheetandtheobjectdependingoneachother.

Inthefollowingexample,wewillcreateacoupleofobjects,retrievesomeoftheirproperties

inaspreadsheet,thenusethespreadsheettodirectlydrivepropertiesofotherobjects.se

Readingproperties

StartbyswitchingtothePartWorkbench,andcreateacoupleofobjects:a box,a

cylinderanda sphere.

EdittheirPlacementproperty(orusethe DraftMovetool)toplacethemalittleapart,

sowecanwatchbettertheeffectsofwhatwe'lldo:

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Now,lt'sextractsomeinformationabouttheseobjects.SwitchtotheSpreadsheet

Workbench

Pressthe NewSpreadsheetbutton

Double-clickthenewSpreadsheetobjectinthetreeview.Thespreadsheeteditor

opens:

ThespreadsheeteditorofFreeCAD,althoughitisnotascompleteandpowerfulasthemore

completespreadsheetapplicationswelistedabove,hasneverthelessmostofthebasictools

andfunctionsthatarecommonlyused,suchasthepossibilitytochangetheaspectofthe

cells (size, color, alignment), join and split cells, use formulas such as =2+2, or reference

othercellswith=B1.

In FreeCAD, to these common behaviours, has been added one very interesting: The

possibilitytoreferencenotonlyothercells,butotherobjectsfromthedocument,andretrieve

values from their properties. For example, let's retrieve a couple of properties from the 3

objectswecreatedabove.Propertiesarewhatwecanseeinthepropertieseditorwindow,

undertheDatatab,whenanobjectisselected.

Let'sstartbyenteringacoupleoftextsinthecellsA1,A2amdA3,soweremember

whatiswhatlateron,forexampleCubeLength,CylinderRadiusandSphereRadius.

Toentertext,justwriteinthe"Contents"filedabovethespreadsheet,ordouble-clicka

cell.

Nowlet'sretrievetheactuallengthofourcube.IncellB1,type=Cube.Length.Youwill

noticethatthespreadhseethasanautocompletionmechanism,whichisactuallythe

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134

sameastheexpressioneditorweusedinthepreviouschapter.

DothesameforcellB2(=Cylinder.Radius)andB3(=Sphere.Radius).

Althoughtheseresultsareexpressedwiththeirunits,thevaluescanbemanipulatedas

anynumber,tryforexampleenteringincellC1:=B1*2.

Wecannowchangeoneofthesevaluesintheproperttieseditor,andthechangewillbe

immediatelyreflectedinthespreadsheet.Forexample,let'schangethelengthofour

cubeto20mm:

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The Spreadsheet Workbench page will describe more in detail all the possible operations

andfunctionsthatyoucanuseinspreadsheets.

Writingproperties

Another very interesting use of the Spreadsheet Workbench in FreeCAD is to do the

contraryofwhatwehavebeendoinguntilnow:Insteadofreadingthevaluesofpropertiesof

3D objects, we can also assign values to these objects. Remember, however, one of the

fundamentalrulesofFreeCAD:Circulardependenciesareforbidden.Wecanthereforenot

usethe same spreadsheetto readand write values to a 3D object. That would make the

objectdependonthespreadsheet,whichwouldalsodependontheobject.Instead,wewill

createanotherspreadsheet.

Wecannowclosethespreadsheettab(underthe3Dview).Thisisnotmandatory,

thereisnoprobleminkeepingseveralspreadsheetwindowsopen.

Pressthe NewSpreadsheetbuttonagain

Changethenameofthenewspreadsheettosomethingmoremeaningful,suchasInput

(dothisbyright-clickingthenewspreadsheetobject,andchoosingRename).

Double-clicktheInputspreadsheettoopenthespreadsheeteditor.

IncellA1,let'sputadescriptivetext,forexample:"Cubedimensions"

IncellB1,write=5mm(usingthe=signmakessurethevalueisinterpretedasaunit

value,notatext).

Nowtobeabletousethisvalueoutsidethespreadsheet,weneedtogiveaname,or

alias,totheB1cell.Right-clickthecells,clickPropertiesandselecttheAliastab.Give

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136

itaname,suchascubedims:

PressOK,thenclosethespreadsheettab

Selectthecubeobject

Inthepropertieseditor,clickthelittle expressioniconattherightsideoftheLength

field.Thiswillopenthenexpressionseditor,whereyoucanwrite

Spreadsheet001.cubedims.RepeatthisforHeightandWidth:

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Youmightwonderwhywehadtouse"Spreadsheet001"insteadof"Input"intheexpression

above.Thisisbeacauseeachobject,inaFreeCADdocument,hasaninternalname,which

is unique in the document, and a label, which is what appears in the tree view. If you

unchecktheappropriateoptioninthepreferencessettings,FreeCADwillallowyoutogive

the same label to more than one object. This is why all operations that must identify an

objectwithabsolutelynodoubt,willusetheinternalnameinsteadofthelabel,whichcould

designatemorethanoneobject.Theeasiestwaytoknowtheinternalnameofanobjectis

bykeepingtheselectionpanel(menuEdit->Panels)open,itwillalwaysindicatetheinternal

nameofaselectedobject:

By using cell aliases in spreadsheets, we are able to use a spreadsheet to store "master

values"inaFreeCADdocument.Thiscanbeused,forexample,tohaveamodelofapiece

ofcertaindimensions,andtostorethesedimensionsinaspreadsheet.Itbecomesthenvery

easytoproduceanothermodelwithdifferentdimensions,itisjustamatterofopeningthe

fileandchangingacoupleofdimensionsinthespreadsheet.

Finally,notethattheconstraintsinsideasketchcanalsoreceivethevalueofaspreadsheet

cell:

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You can also give aliases to dimensional constraints (horizontal, vertical or distance) in a

sketch(youcanthenusethatvaluefromoutsidethesketchaswell):

Download

Thefileproducedinthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/spreadsheet.FCStd

Readmore

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TheSpreadsheetWorkbench:http://www.freecadweb.org/wiki/index.php?

title=Spreadsheet_Module

TheExpressionsengine:http://www.freecadweb.org/wiki/index.php?title=Expressions

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CreatingFEManalyses

FEMstandsforFiniteElementMethod.Itisavastmathematicalsubject,butinFreeCADwe

canresumeitasawaytocalculatepropagationsinsidea3Dobject,bycuttingitintosmall

pieces,andanalyzingtheimpactofeachsmallpieceoveritsneighbours.Thishasseveral

usesintheengineeringandelectomagnetismfields,butwewilllookheremoreindepthat

one use that is already well developed in FreeCAD, which is simulating deformations in

objectswhicharesubmittedtoforcesandweights.

ObtainingsuchsimulationisdoneinFreeCADwiththeFEMWorkbench.Itinvolvesdifferent

steps: Preparing the geometry, setting its material, performing the meshing (division into

smaller parts, like we did in the Preparing objects for 3D printing chapter, and finally

calculatingthesimulation.

PreparingFreeCAD

Thesimulationitselfisdonebyanotherpieceofsoftware,thatisusedbyFreeCADtoobtain

the results. As there are several interesting open-source FEM simulation applications

available,theFEMWorkbenchhasbeenmadetobeabletousemorethanone.However,

currentlyonlyCalculiXisfullyimplemented.Anotherpieceofsoftware,calledNetGen,which

isresponsibleforgeneratingthesubdivisionmesh,isalsorequired.Detailedinstructionsto

installthesetwocomponentsareprovidedintheFreeCADdocumentation.

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141

Preparingthegeometry

We will start with the house we modelled in the BIM modeling chapter. However, some

changeshavetobemadetomakethemodelsuitableforFEMcalculations.Thisinvolves,

basically,discardingtheobjectsthatwedon'twanttoincludeinthecalculaiton,suchasthe

doorandwindow,andjoiningalltheremainingobjectsintoone.

Loadthehousemodelwemodeledearlier

Deleteorhidethepageobject,thesectionplanesandthedimensions,sowestayonly

withourmodel

Hidethewindow,thedoorandthegroundslab

Alsohidethemetalbeamsfromtheroof.Sincetheyareverydifferentobjectsfromthe

restofthehouse,wewillsimplifyourcalculationbynotincludingit.Instead,wewill

considerthattheroofslabisdirectlyplacedontopofthewall.

Nowmovetheroofslabdownsoitrestsontopofthewall:EdittheRectangleobject

thatweusedasabaseoftheroofslab,andchangeit'sPlacement->Position->Xvalue

from3.18mto3.00m

Ourmodelisnowclean:

TheFEMWorkbenchcancurrentlycalculatedeformationsononesingleobjectonly.

Therefore,weneedtojoinourtwoobjects(thewallandtheslab).SwitchtothePart

Workbench,selectthetwoobjects,andpressthe Fuse.Wenowhaveobtainedone

fusedobject:

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142

Creatingtheanalysis

WearenowreadytostartaFEManalysis.Let'sswitchtotheFEMWorkbench

Selectthefusionobject

Pressthe NewAnalysisbutton

Anewanalysiswillbecreatedandasettingspanelsopened.Hereyoucandefinethe

meshingparameterstobeusedtoproducetheFEMmesh.Themainsettingtoeditis

theMaxSizewhichdefinesthemaximumsize(inmillimeters)ofeachpieceofthe

mesh.Fornow,wecanleavethedefaultvalueof1000:

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143

AfterpressingOKandafewsecondsofcalculaiton,ourFEMmeshisnowready:

Wecannowdefinethematerialtobeappliedtoourmesh.Thisisimportantbecause

dependingonthematerialstrength,ourobjectwillreactdifferentlytoforcesappliedtoit.

Selecttheanalysisobject,andpressthe NewMaterialbutton.

Ataskpanelwillopentoallowustochooseamaterial.IntheMaterialdrop-downlist,

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144

choosetheConcrete-genericmaterial,andpressOK.

Wearenowreadytoapplyforces.Let'sstartbyspecifyingwhichfacesarefixedintothe

groundandcanthereforenotmove.Pressthe FixedConstraintbutton.

ClickonthebottomfaceofourbuildingandpressOK.Thebottomfaceisnowindicated

asunmovable:

Wewillnowaddaloadonthetopface,thatcouldrepresente,forexample,amassive

CreatingFEManalyses

145

weightbeingspreadontheroof.Forthiswewilluseapressureconstraint.Pressthe

PressureConstraintbutton.

Clickthetopfaceoftheroof,setthepressureto10MPa(thepressureisappliedby

squaremillimeter)andclicktheOKbutton.Ourforceisnowapplied:

Wearenowreadytostartthecalculation.SelecttheCalculiXobjectinthetreeview,

andpressthe StartCalculationbutton.

Inthetaskpanelthatwillopen,clickfirsttheWrite.inpfilebuttontocreatetheinputfile

forCalculiX,thentheRunCalculiXbutton.Afewmomentslater,thecalculationwillbe

done:

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146

Wecannowlookattheresults.Closethetaskpanel,andseethatanewResults

objecthasbeenaddedtoouranalysis.

Double-clicktheResultsobject

Setthetypeofresultthatyouwanttoseeonthemesh,forexample"absolute

displacement",ticktheshowcheckboxunderDisplacement,andmovetheslidernext

toit.Youwillbeabletoseethedeformationgrowingasyouapplymoreforce:

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147

TheresultsdisplayedbytheFEMworkbenchareofcoursecurrentlynotenoughtoperform

real-lifedecisionsaboutstructuresdimensionningandmaterials.However,theycanalready

givepreciousinformationabouthowtheforcesflowthroughastructure,andwhicharethe

weakareasthatwillbearthemorestress.

Downloads

Thefilecreatedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/fem.FCStd

Readmore

TheFEMWorkbench:http://www.freecadweb.org/wiki/index.php?title=Fem_Workbench

InstallingrequiredFEMcomponents:http://www.freecadweb.org/wiki/index.php?

title=FEM_Install

CalculiX:http://www.calculix.de/

NetGen:https://sourceforge.net/projects/netgen-mesher/

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148

Creatingrenderings

Incomputertalk,arenderingisawordusedtodescribeaniceimageproducedfroma3D

model.Ofcourse,wecouldsaythatwhatseseeintheFreeCAD3Dviewisalreadynice.

ButanybodywhosawarecentHollywoodmovieknowsthatitispossibletoproduceimages

withacomputerthatarealmostundistinguishablefromaphotograph.

Ofcourse,producingsuchphoto-realisticimagesrequiresalotofwork,anda3Dapplication

that offers specific tools for that, such as precise controls for materials and lighting.

FreeCAD being an application more geared towards technical modeling, it doesn't feature

anyadvancedrenderingtool.

Fortunately, the opens-source world offers many applications to produce realistic images.

Probably the most famous one is Blender, which is very popular and widely used in the

movies and gaming industries. 3D models can very easily and faithfully be exported from

FreeCADandimportedintoBlender,whereyoucanaddrealisticmaterialsandillumination,

andproducethefinalimagesorevenanimations.

Some other open-source rendering tools are made to be used inside another application,

andwilltakecareofdoingthecomplexcalculationstoproducerealisticimages.Throughits

Raytracing Workbench, FreeCAD can use two of these rendering tools: POV-Ray and

Luxrender.POV-Rayisaveryoldproject,andisconsideredaclassicalraytracing engine,

whileLuxrenderismuchnewer,andiscategorizedasanunbiasedrenderer.Bothhavetheir

strengthsandweaknesses,dependingonthetypeofimageonewantstorender.Thebest

waytoknowistolookatexamplesonbothengineswebsites.

Installation

BeforebeingabletousetheRaytracingWorkbenchinFreeCAD,oneofthesetworendering

applicationsneedstobeinstalledonyoursystem.Thisisusuallyverystraightforward,both

provideinstallersformanyplatformsorareusuallyincludedinthesoftwarerepositoriesof

mostLinuxdistributions.

OncePOV-RayorLuxrenderisinstalled,weneedtosetthepathtotheirmainexecutablein

the FreeCAD preferences. This is usually only required on Windows and Mac. On Linux

FreeCAD will pick it from the standard locations. The location of the povray or luxrender

executables can be found by simply searching your system for files named povray (or

povray.exeonWindows)andluxrender(orluxrender.exeonWindows).

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149

Inthispreferencesscreenwecanalsosetthedesiredimagesizewewanttoproduce.

RenderingwithPovRay

Wewillusethetablewehavebeenmodelinginthetradtionalmodelingchaptertoproduce

renderingswithPovRayandLuxrender.

Startbyloadingthetable.FCStdfilethatwemodeledearlierorfromthelinkatthe

bottomofthischapter.

Pressthesmalldownarrownexttothe NewPovrayprojectbutton,andchoosethe

RadiosityNormaltemplate

Awarningmessagemightappeartellingyouthatthecurrent3Dviewisnotin

perspectivemodeandtherenderingwillthereforediffer.CorrectthisbychoosingNo,

choosingmenuView->PerspectiveviewandchoosingtheRadiosityNormaltemplate

again.

Youmightalsotryothertemplatesafteryoucreatedanewproject,simplybyeditingits

Templateproperty.

Anewprojecthasnowbeencreated:

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150

Thenewprojecthasadoptedthepointofviewofthe3Dviewasitwasatthemoment

wepressedthebutton.Wecanchangetheview,andupdatetheviewpositionstoredin

thepovrayprojectanytime,bypressingthe Resetcamerabutton.

TheRaytracingWorkbenchworksthesamewayastheDrawingWorkbench:Oncea

projectfolderiscreated,wemustaddViewsofourobjectstoit.Wecannowdothatby

selectingalltheobjectsthatcomposethetable,andpressthe Insertpartbutton:

Theviewshavetakenthecolorandtransparencyvaluesfromtheiroriginalparts,but

youcanchangethatinthepropertiesofeachindividualviewifyouwish.

Wearenowreadytoproduceourfirstpovrayrender.Pressthe Renderbutton.

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151

Youwillbeaskedtogiveafilenameandpathforthe.pngimagethatwillbesavedby

povray.

Thepovraywillthenopenandcalculatetheimage.

Whenthisisdone,simplyclicktheimagetoclosethepovraywindow.Theresulting

imagewillbeloadedinFreeCAD:

RenderingwithLuxRender

RenderingwithLuxrenderworksalmostthesameway.Wecanleaveourfileopenand

createanewLuxrenderprojectinthesamefile,orreloadittostartfromscratch.

Pressthelittledownarrownexttothe NewLuxrenderprojectbuttonandchoosethe

LuxOutdoortemplate.

Selectallthecomponentsofthetable.Ifyoustillhavethepovrayprojectinyour

document,besuretoalsoselecttheluxprojectitself,sotheviewscreatedinthenext

stepwon'tgointhewrongprojectbymistake.

Pressthe Insertpartbutton.

Selecttheluxrenderproject,andpressthe Renderbutton.

Luxrenderworksdifferentlythanpovray.Whenyoustarttherender,theluxrender

applicationwillopenandimmediatelystartrendering:

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152

Ifyouleavethatwindowopen,Luxrenderwillcontinuecalculatingandrenderingforever,

progressivelyrefiningtheimage.Itisuptoyoutodecidewhentheimagehasreacha

sufficientqualityforyourneeds,andstoptherender.

Therearealsomanycontrolstoplaywith,ontheleftpanel.Allthesecontrolswill

changetheaspectoftheimagebeingrenderedonthefly,withoutstoppingthe

rendering.

Whenyoufeelthequalityisgoodenough,simplypressRender->stop,andthenFile-

>Exporttoimage->Tonemappedlowdynamicrangetosavetherenderedimagetoa

pngfile.

You can extend greatly the render possibilities of FreeCAD by creating new templates for

povrayorluxrender.ThisisexplainedintheRaytracingWorkbenchdocumentation.

Downloads

Thetablemodel:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/table.FCStd

Thefileproducedduringthisexercise:https://github.com/yorikvanhavre/FreeCAD-

manual/blob/master/files/render.FCStd

Readmore

TheRaytracingWorkbench:http://www.freecadweb.org/wiki/index.php?

title=Raytracing_Module

Blender:http://www.blender.org

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POV-Ray:http://www.povray.org

Luxrender:http://www.luxrender.net

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154

Pythonscripting

155

Agentleintroduction

Python is a widely popular, open-source programming language, very often used as a

scriptinglanguage,embeddedinapplications,asthisisthecasewithFreeCAD.Italsohasa

seriesoffeaturesthatmakesitspeciallyinterestingforusFreeCADusers:Itisveryeasyto

learn,speciallyforpeoplewhohadneverprogrammedbefore,anditisembeddedinmany

otherapplications,whichmakesitaveryvaluabletooltolearn,asyouwillbeabletouseit

inmanyotherapplications,suchasBlender,InkscapeorGRASS.

FreeCADmakesanextensiveuseofPython.Withit,youcanaccessandcontrolalmostany

feature of FreeCAD. You can for example create new objects, modify their geometry,

analyze their contents, or even create new interface controls, tools and panels. Some

workbenches of FreeCAD and most of the addon workbenches are fully programmed in

python. FreeCAD has an advanced python console, available from menu View->Panels-

>Python console. It is often useful to perform operations for which there is no toolbar

buttonyet,ortocheckshapesforproblems,ortoperformrepetitivetasks:

Butthepythonconsolealsohasanotherveryimportantuse:Everytimeyoupressatoolbar

button,orperformotheroperationsinFreeCAD,somepythoncodeisprintedintheconsole

andexecuted.By leavingthePython consoleopen,you canlitterallysee thepythoncode

unfold as you work, and in no time, almost without knowing it, you will be learning some

pythonlanguage.

FreeCADalsohasamacrossystem,whichallowsyoutorecordactionstobereplayedlater.

ThissystemalsousesthePythonconsole,bysimplyrecordingeverythingthatisdoneinit.

Inthischapter,wewilldiscoververygenerallythePythonlanguage.Ifyouareinterestedin

learningmore,theFreeCADdocumentationwikihasanextensivesectionrelatedtopython

programming.

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156

Writingpythoncode

TherearetwoeasywaystowritepythoncodeinFreeCAD:Fromthepythonconsole(menu

View->Panels->PythonConsole),orfromtheMacroeditor(menuTools->Macros->

New). In the console, you write python commands one by one, which are executed when

youpressreturn,whilethemacroscancontainamorecomplexscriptmadeofseverallines,

whichisexecutedonlywhenthemacroislaunchedfromthesameMacroswindow.

Inthischapter,youwillbeabletousebothmethods,butitishighlyrecommendedtousethe

PythonConsole,sinceitwillimmediatelyinformyouofanyerroryoucoulddowhiletyping.

IfthisisthefirsttimeyouaredoingPythoncoding,considerreadingthisshortintroductionto

Pythonprogrammingbeforegoingfurther,itwillmakethebasicconceptsofPythonclearer.

ManipulatingFreeCADobjects

Let'sstartbycreatinganewemptydocument:

doc=FreeCAD.newDocument()

If you type this in the FreeCAD python console, you will notice that as soon as you type

"FreeCAD."(thewordFreeCADfollowedbyadot),awindowspopsup,allowingtoquickly

autocomplete the rest of your line. Even better, each entry in the autocomplete list has a

tooltipexplainingwhatitdoes.Thismakesitveryeasytoexplorethefunctionalityavailable.

Beforechoosing"newDocument",havealookattheotheroptionsavailable.

AssoonasyoupressEnterournewdocumentwillbecreated.Thisissimilartopressing

the"newdocument"buttononthetoolbar.InPython,thedotisusedtoindicatesomething

that is contained inside something else (newDocument is a function that is inside the

FreeCAD module). The window that pops up therefore shows you everything that is

contained inside "FreeCAD". If you would add a dot after newDocument, instead of the

parentheses, it would show you everything that is contained inside the newDocument

function.TheparenthesesaremandatorywhenyouarecallingaPythonfunction,suchas

thisone.Wewillillustratethatbetterbelow.

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157

Nowlet'sgetbacktoourdocument.Let'sseewhatwecandowithit:

doc.

Explorethe availableoptions.Usually namesthat beginwith acapital letterare attributes,

they contain a value, while names that begin with small letter are functions (also called

methods),they"dosomething".Namesthatbeginwithanunderscoreareusuallytherefor

theinternalworkingofthemodule,andyoushouldn'tcareaboutthem.Let'suseoneofthe

methodstoaddanewobjecttoourdocument:

box=doc.addObject("Part::Box","myBox")

Ourboxisaddedinthetreeview,butnothinghappensinthe3Dviewyet,becausewhen

working from Python, the document is never recomputed automatically. We must do that

manually,wheneverweneed:

doc.recompute()

Now our box appeared in the 3D view. Many of the toolbar buttons that add objects in

FreeCADactuallydotwothings:addtheobject,andrecompute.Ifyouturnedonthe"show

script commands in python console" option above, try now adding a sphere with the

appropriate button in the Part Workbench, and you will see the two lines of python code

beingexecutedoneaftertheother.

YoucangetalistofallpossibleobjecttypeslikePart::Box:

doc.supportedTypes()

Nowlet'sexplorethecontentsofourbox:

box.

You'llimmediatelyseeacoupleofveryinterestingthingssuchas:

box.Height

Thiswillprintthecurrentheightofourbox.Nowlet'strytochangethat:

box.Height=5

Ifyou selectyour boxwiththe mouse,you willsee thatin theproperties panel,underthe

Data tab, our Height property appears with the new value. All properties of a FreeCAD

objectthatappearintheDataandViewtabsaredirectlyaccessiblebypythontoo,bytheir

names,likewedidwiththeHeightproperty.Datapropertiesareaccesseddirectlyfromthe

objectitself,forexample:

box.Length

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158

View properties are stored inside a ViewObject. Each FreeCAd object possesses a

ViewObject,whichstoresthevieualpropertiesoftheobject.WhenrunningFreeCADwithout

itsGraphicalInterface(forexamplewhenlaunchingitfromaterminalwiththe-ccommand

line option, or using it from another Python script), the ViewObject is not available, since

thereisnovisualatall.

Forexample,toaccessthelinecolorofourbox:

box.ViewObject.LineColor

VectorsandPlacements

Vectorsareaveryfundamentalconceptinany3Dapplication.Itisalistof3numbers(x,y

and z), describing a point or position in the 3D space. A lot of things can be done with

vectors, such as additions, subtractions, projections and much more. In FreeCAD vectors

worklikethis:

myvec=FreeCAD.Vector(2,0,0)

print(myvec)

prnimarkdownt(myvec.x)

print(myvec.y)

othervec=FreeCAD.Vector(0,3,0)

sumvec=myvec.add(othervec)

Another common feature of FreeCAD objects is their Placement. As we saw in earlier

chapters, each object has a Placement property, which contains the position (Base) and

orientation (Rotation) of the object. It is easy to manipulate from Python, for example to

moveourobject:

print(box.Placement)

print(box.Placement.Base)

box.Placement.Base=sumvec

otherpla=FreeCAD.Placement()

otherpla.Base=FreeCAD.Vector(5,5,0)

box.Placement=otherpla

Readmore

Python:https://www.python.org/

WorkingwithMacros:http://www.freecadweb.org/wiki/index.php?title=Macros

IntroductiontoPythonscripting:http://www.freecadweb.org/wiki/index.php?

title=Introduction_to_Python

UsingPythoninFreeCAD:http://www.freecadweb.org/wiki/index.php?

title=Python_scripting_tutorial

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ThePythonscriptingwikihub:http://www.freecadweb.org/wiki/index.php?

title=Power_users_hub

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Creatingandmanipulatinggeometry

Inthepreviouschapters,welearnedaboutthedifferentworkbenchesofFreeCAD,andthat

each of them implements its own tools and geometry types. The same concepts applies

whenworkingfromPythoncode.

We also saw that the big majority of the FreeCAD workbenches depend on a very

fundamental one: the Part Workbench. In fact, may other workbenches, such as Draft or

Arch, do exactly what we will do in this chapter: They use Python code to create and

manipulatePartgeometry.

SothefirstthingweneedtodotoworkwithPartgeometry,istodothePythonequivalentto

switchingtothePartWorkbench:importthePartmodule:

importPart

Takeaminutetoexplorethecontentsof thePartmodule,bytyping Part. and browsing

through the different methods offered there. The Part module offers several convenience

fuctionssuchasmakeBox,makeCircle,etc...whichwillinstantlybuildanobjectforyou.Try

this,forexample:

Part.makeBox(3,5,7)

When you press Enter after typing the line above, nothing will appear in the 3D view, but

somethinglikethiswillbeprintedonthePythonConsole:

<Solidobjectat0x5f43600>

Thisiswhereanimportantconcepttakesplace.WhatwecreatedhereisaPartShape.Itis

not a FreeCAD document object (yet). In FreeCAD, objects and their geometry are

independent. Think of a FreeCAD document object as a container, that will host a shape.

ParametricobjectswillalsohavepropertiessuchasLengthandWidth,andwillrecalculate

their Shape on-the-fly, whenever one of the properties changes.What we did here is

calculateashapemanually.

Wecannoweasilycreatea"generic"documentobjectinthecurrentdocument(makesure

youhaveatleastonenewdocumentopen),andgiveitaboxshapelikewejustmade:

boxShape=Part.makeBox(3,5,7)

myObj=FreeCAD.ActiveDocument.addObject("Part::Feature","MyNewBox")

myObj.Shape=boxShape

FreeCAD.ActiveDocument.recompute()

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Notehowwehandled myObj.Shape,seethat itisdoneexactly likewedidin theprevious

chapter,whenwechangedotherpropertiesofanobject,suchas box.Height=5.Infact,

Shapeisalsoaproperty,justlikeHeight.OnlyittakesaPartShape,notanumber.Innext

chapterwewillhaveadeeperlookathowthoseparametricobjectsareconstructed.

For now, let's explore our Part Shapes more in detail. At the end of the chapter about

traditional modeling with the Part Workbench we showed a table that explains how Part

Shapes are constructed, and their different components (Vertices, edges, faces, etc). The

exactsamecomponentsexisthereandcanberetrievedfromPython.AllPartShapealways

havethefollowingattributes:Vertexes,Edges,Wires,Faces,ShellsandSolids.Allofthem

arelists,thatcancontainanynumberofelementsorbeempty:

print(boxShape.Vertexes)

print(boxShape.Edges)

print(boxShape.Wires)

print(boxShape.Faces)

print(boxShape.Shells)

print(boxShape.Solids)

Forexample,let'sfindtheareaofeachfaceofourboxshapeabove:

forfinboxShape.Faces:

print(f.Area)

Or,foreachedge,itsstartpointandendpoint:

foreinboxShape.Edges:

print("Newedge")

print("Startpoint:")

print(e.Vertexes[0].Point)

print("Endpoint:")

print(e.Vertexes[1].Point)

Asyousee,ifourboxShapehasa"Vertexes"attribute,eachEdgeoftheboxShapealsohas

a"Vertexes"attribute.Aswecanexpect,theboxShapewillhave8vertices,whiletheedge

willonlyhave2,whicharebothpartofthelistof8.

Wecanalwayscheckwhatisthetypeofashape:

print(boxShape.ShapeType)

print(boxShape.Faces[0].ShapeType)

print(boxShape.Vertexes[2].ShapeType)

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SotoresumethewholediagramofPartShapes:EverythingstartswithVertices.Withoneor

twovertices,youformanEdge(fullcircleshaveonlyonevertex).WithoneormoreEdges,

you form a Wire. With one or more closed Wires, you form a Face (the additional Wires

become"holes" inthe Face). Withone ormore Faces,youform aShell. Whena Shell is

fullyclosed(watertight),youcanformaSolidfromit.Andfinally,youcanjoinanynumberof

Shapesofanytypestogether,whichisthencalledaCompound.

Wecannowtrycreatingcomplexshapesfromscratch,byconstructingalltheircomponents

onebyone.Forexample,let'strytocreateavolumelikethis:

Wewillstartbycreatingaplanarshapelikethis:

First,let'screatethefourbasepoints:

V1=FreeCAD.Vector(0,10,0)

V2=FreeCAD.Vector(30,10,0)

V3=FreeCAD.Vector(30,-10,0)

V4=FreeCAD.Vector(0,-10,0)

Thenwecancreatethetwolinearsegments:

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163

L1=Part.Line(V1,V2)

L2=Part.Line(V4,V3)

Notethat we didn'tneed tocreate Vertices? Wecould immediately createPart.Lines from

FreeCADVectors.Thisisbecauseherewehaven'tcreatedEdgesyet.APart.Line(aswell

asPart.Circle,Part.Arc,Part.EllipseorPArt.BSpline)doesnotcreateanEdge,butrathera

basegeometryonwhichanEdgewillbecreated.Edgesarealwaysmadefromsuchabase

geometry,whichisstoreditsCurveattribute.SoifyouhaveanEdge,doing:

print(Edge.Curve)

willshowyouwhatkindofEdgethisis,thatis,ifitisbasedonaline,anarc,etc...Butlet's

comebacktoourexercise,andbuildthearcsegments.Forthis,wewillneedathirdpoint,

sowecanusetheconvenientPart.Arc,whichtakes3points:

VC1=FreeCAD.Vector(-10,0,0)

C1=Part.Arc(V1,VC1,V4)

VC2=FreeCAD.Vector(40,0,0)

C2=Part.Arc(V2,VC2,V3)

Nowwehave2lines(L1andL2)and2arcs(C1andC2).Weneedtoturnthemintoedges:

E1=Part.Edge(L1)

E2=Part.Edge(L2)

E3=Part.Edge(C1)

E4=Part.Edge(C2)

Alternatively, base geometries also have a toShape() function that do exactly the same

thing:

E1=L1.toShape()

E2=L2.toShape()

...

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164

OncewehaveaseriesofEdges,wecannowformaWire,bygivingitalistofEdges.We

don'tneedtotakecareoftheorder.OpenCasCade,thegeometry"engine"ofFreeCAD,is

extraordinarilytoleranttounorderedgeometry.Itwillsortoutwhattodo:

W=Part.Wire([E1,E2,E3,E4])

AndwecancheckifourWirewascorrectlyunderstood,andthatitiscorrecltyclosed:

print(W.isClosed())

Whichwillprint"True"or"False".InordertomakeaFace,weneedclosedWires,soitis

alwaysagoodideatocheckthatbeforecreatingtheFace.NowwecancreateaFace,by

givingitasingleWire(oralistofWiresifwehadholes):

F=Part.Face(W)

Thenweextrudeit:

P=F.extrude(FreeCAD.Vector(0,0,10))

NotethatPisalreadyaSolid:

print(P.ShapeType)

BecausewhenextrudingasingleFace,wealwaysgetaSolid.Thiswouldn'tbethecase,for

example,ifwehadextrudedtheWireinstead:

S=W.extrude(FreeCAD.Vector(0,0,10))

print(s.ShapeType)

Whichwillofcoursegiveusahollowshell,withthetopandbottomfacesmissing.

Now that we have our final Shape, we are anxious to see it on screen! So let's create a

genericobject,andattributeitournewSolid:

myObj2=FreeCAD.ActiveDocument.addObject("Part::Feature","My_Strange_Solid")

myObj2.Shape=P

FreeCAD.ActiveDocument.recompute()

Altenatively,thePartmodulealsoprovidesashortcutthatdoestheaboveoperationquicker

(butyoucannotchoosethenameoftheobject):

Part.show(P)

Alloftheabove,andmuchmore,isexplainedindetailonthePartScriptingpage,together

withexamples.

Readmore:

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165

ThePartWorkbench:http://www.freecadweb.org/wiki/index.php?title=Part_Workbench

Partscripting:http://www.freecadweb.org/wiki/index.php?

title=Topological_data_scripting

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166

Creatingparametricobjects

In the previous chapter, we saw how to create Part geometry, and how to display it on

screen,byattachingittoa"dumb"(non-parametric)documentobject.Thisistediouswhen

wewant tochange theshapeof thatobject. Wewouldneedto createa newshape, then

attributeitagaintoourobject.

However,wealsosawinalltheprecedingchaptersofthismanualhowparametricobjects

arepowerful.Weonlyneedtochangeoneproperty,andtheshapeisrecalculatedon-the-fly.

Internally, parametricobjects don'tdo anythingdifferentthan wejustdid: Theyrecalculate

the contents of their Shape property, over and over, each time another property has

changed.

FreeCADprovidesaveryconvenientsystemtobuildsuchparametricobjectsfullyinPython.

TheyconsistofasimplePythonclass,whichdefinesallthepropertiesthattheobjectneeds,

and what will happen when one of these properties changes. The structure of such

parametricobjectisassimpleasthis:

classmyParametricObject:

def__init__(self,obj):

obj.Proxy=self

obj.addProperty("App::PropertyFloat","MyLength")

...

defexecute(self,obj):

print("Recalculatingtheshape...")

print("ThevalueofMyLengthis:")

print(obj.MyLength)

...

All Python classes usually have an init method. What is inside that method is executed

whenthatclassisinstantiated(whichmeans,inprogrammingslang,thataPythonObjectis

createdfromthatclass.Thinkofaclassasa"template"tocreatelivecopiesofit).Inourinit

functionhere,wedotwoimportantthings:1)storeourclassitselfintothe"Proxy"attributeof

ourFreeCAD documetn object,that is,the FreeCAD documentobject willcarry this code,

inside itself, and 2) create all the properties our object needs. There are many types of

propertiesavailable,youcangetthefulllistbytypingthiscode:

FreeCAD.ActiveDocument.addObject("Part::FeaturePython","dummy").supportedProperties()

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167

Then, the second important part is the execute method. Any code in this method will be

executedwhentheobjectismarkedtoberecomputed,whichwillhappenwhenaproperty

hasbeen changed.That is allthere is toit. Insideexecute, youneed to doall thatneeds

tobedone,thatis,calculatinganewshape,andattributingtotheobjectitselfwithsomething

like obj.Shape = myNewShape. That is why the execute method takes an "obj" argument,

whichwillbetheFreeCADdocumentobjectitself,sowecanmanipulateitinsideourpython

code.

One last thing is important to remember: When you create such parametric objects in a

FreeCADdocument,whenyousavethefile,thepythoncodeaboveisnotstoredinsidethe

file.Thisisforsecurityreasons,ifaFreeCADfilecontainedcode,itwouldbepossiblefor

someone to distribute FreeCAD files containing malicious code that could harm other

people's computers. So, if you distribute a file that contains objects made with the above

code,suchcodemustalsobepresentonthecomputerthatwillopenthefile.Theeasiest

waytoachievethatisusuallytosavethecodeaboveinamacro,anddistributethemacro

together with your FreeCAD file, or share your macro on the FreeCAD macros repository

whereanybodycandownloadit.

Below,wewilldoasmallexercise,buildingaparametricobjectthatisasimpleparametric

rectangular face. More complex examples are available on the parametric object example

andintheFreeCADsourcecodeitself.

Wewillgiveourobjecttwoproperties:LengthandWidth,whichwewillusetoconstructa

rectangle. Then, since our object will already have a pre-built Placement property (all

geometric object have one by default, no need to add it ourselves), we will displace our

rectangletothelocation/rotationsetinthePlacement,sotheuserwillbeabletomovethe

rectangleanywherebyeditingthePlacementproperty.

Creatingparametricobjects

168

classParametricRectangle:

def__init__(self,obj):

obj.Proxy=self

obj.addProperty("App::PropertyFloat","Length")

obj.addProperty("App::PropertyFloat","Width")

defexecute(self,obj):

#weneedtoimporttheFreeCADmoduleheretoo,becausewemightberunningouto

ftheConsole

#(inamacro,forexample)wheretheFreeCADmodulehasnotbeenimportedautomat

ically

importPart,FreeCAD

#firstweneedtomakesurethevaluesofLengthandWidtharenot0

#otherwisethePart.Linewillcomplainthatbothpointsareequal

if(obj.Length==0)or(obj.Width==0):

#ifyes,exitthismethodwithoutdoinganything

return

#wecreate4pointsforthe4corners

v1=FreeCAD.Vector(0,0,0)

v2=FreeCAD.Vector(obj.Length,0,0)

v3=FreeCAD.Vector(obj.Length,obj.Width,0)

v4=FreeCAD.Vector(0,obj.Width,0)

#wecreate4edges

e1=Part.Line(v1,v2).toShape()

e2=Part.Line(v2,v3).toShape()

e3=Part.Line(v3,v4).toShape()

e4=Part.Line(v4,v1).toShape()

#wecreateawire

w=Part.Wire([e1,e2,e3,e4])

#wecreateaface

f=Part.Face(w)

#AllshapeshaveaPlacementtoo.Wegiveourshapethevalueoftheplacement

#setbytheuser.Thiswillmove/rotatethefaceautomatically.

f.Placement=obj.Placement

#alldone,wecanattributeourshapetotheobject!

obj.Shape=f

InsteadofpastingtheabovecodeinthePythonconsole,we'dbettersaveitsomewhere,so

we can reuse and modify it later. For example in a new macro (menu Tools -> Macros ->

Create). Name it, for example, "ParamRectangle". However, FreeCAD macros are saved

witha.FCMacroextension,whichPythondoesn'trecognizewhenusing import.So,before

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using the above code, we will need to rename the ParamRectangle.FCMacro file to

ParamRectangle.py. This can be done simply from your file explorer, by navigating to the

MacrosfolderindicatedinmenuTools->Macros.

Oncethatisdone,wecannowdothisinthePythonConsole:

importParamRectangle

By exploring the contents of ParamRectangle, we can verify that it contains our

ParametricRectangleclass.

To create a new parametric object using our ParametricRectangle class, we will use the

following code. Observe that we use Part::FeaturePython instead of Part::Feature that we

have been using in the previous chapters (The Python version allows to define our own

parametricbehaviour):

myObj=FreeCAD.ActiveDocument.addObject("Part::FeaturePython","Rectangle")

ParamRectangle.ParametricRectangle(myObj)

myObj.ViewObject.Proxy=0#thisismandatoryunlesswecodetheViewProvidertoo

FreeCAD.ActiveDocument.recompute()

Nothing will appear on screen just yet, because the Length and Width properties are 0,

which will trigger our "do-nothing" condition inside execute. We just need to change the

valuesofLengthandWidth,andourobjectwillmagicallyappearandberecalculatedon-the-

fly.

Of course it would be tedious to have to type these 4 lines of Python code each time we

wanttocreateanewparametricrectangle.Averysimplewaytosolvethisisplacingthe4

lines above inside our ParamRectangle.py file, at the end, after the end of the

ParametricRectangeclass(WecandothisfromtheMacroeditor).

Now,whenwetype importParamRectangle , a new parametric rectangle will automatically

becreated.Evenbetter,wecanaddatoolbarbuttonthatwilldojustthat:

OpenmenuTools->Customize

Underthe"Macros"tab,selectourParamRectangle.pymacro,fillinthedetailsasyou

wish,andpress"Add":

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UndertheToolbarstab,createanewcustomtoolbarintheworkbenchofyourchoice

(orglobally),selectyourmacroandaddittothetoolbar:

That'sit,wenowhaveanewtoolbarbuttonwhich,whenclicked,willcreatea

parametricrectangle.

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Remeber,ifyouwanttodistributefilescreatedwiththisnewtooltootherpeople,theymust

havetheParamRectangle.pymacroinstalledontheircomputertoo.

Readmore

TheFreeCADmacrosrepository:http://www.freecadweb.org/wiki/index.php?

title=Macros_recipes

Parametricobjectexample:http://www.freecadweb.org/wiki/index.php?

title=Scripted_objects

MoreexamplesintheFreeCADcode:

https://github.com/FreeCAD/FreeCAD/blob/master/src/Mod/TemplatePyMod/FeaturePyt

hon.py

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Creatinginterfacetools

Inthelasttwochapters,wesawhowtocreatePartgeometryandcreateparametricobjects.

One last piece is missing to gain full control over FreeCAD: Create tools that will interact

withtheuser.

Inmanysituations,itisnotveryuser-friendlytoconstructanobjectwithzero-values,likewe

didwiththerectangleinthepreviouschapter,andthenasktheusertofillintheHeightand

WidthvaluesinthePropertiespanel.Thisworksforaverysmallnumberofobjects,butwill

becomeverytediousifyouhavealotofrectanglestomake.Abetterwaywouldbetobe

abletoalreadygivetheHeightandWidthwhencreatingtherectangle.

Pythonoffersabasictooltohavetheuserentertextonscreen:

text=raw_input("Heightoftherectangle?")

print("Theenteredheightis",text)

However,thisrequiresarunningPythonconsole,andwhenrunningourcodefromamacro,

wearenotalwayssurethatthePythonconsolewillbeturnedonontheuser'smachine.

TheGraphicalUserInterface,or GUI,thatis, allthe part ofFreeCAD thatis displayed on

yourscreen(themenu,toolbars,3Dview,etc),isallthereforthatpurpose:interactwiththe

user. FreeCAD's interface is built with Qt), a very common open-source GUI toolkit that

offers a big range of tools such as dialog boxes, buttons, labels, text input boxes or pull-

downmenus(allthesearegenericallycalled"widgets").

The Qt tools are very easy to use from Python, thanks to a Python module called Pyside

(there are several other Python modules to communicate with Qt from Python too). This

module allows you to create and interact with widgets, read what the user did with them

(whatwasfilledintextboxes)ordothingswhen,forexample,abuttonwaspressed.

QtalsoprovidesanotherinterestingtoolcalledQtDesigner,whichistodayembeddedinside

abiggerapplicationcalledQtCreator.Itallowstodesigndialogboxesandinterfacepanels

graphically,insteadofhavingtocodethemmanually.Inthischapter,wewilluseQtCreator

todesigapanelwidgetthatwewilluseintheTaskpanelofFreeCAD.Soyouwillneedto

download and install Qt Creator from its official page if you are on Windows or Mac (on

Linuxitwillusuallybeavailablefromyoursoftwaremanagerapplication).

In the following exercise, we will first create a panel with Qt Creator that asks for length,

width and height values, then we will create a Python class around it, that will read the

valuesenteredbytheuserfromthepanel,andcreateaboxwiththegivendimensions.This

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PythonclasswillthenbeusedbyFreeCADtodisplayandcontrolthetaskpanel:

Let'sstartbycreatingthewidget.StartQtCreator,thenmenuFile->NewFileorProject->

FilesandClasses->Qt->QtDesignerForm->Dialogwithoutbuttons.ClickNext,give

itafilenametosave,clickNext,leaveallprojectfieldstotheirdefaultvalue(""),andCreate.

FreeCAD'sTasksystemwillautomaticallyaddOK/Cancelbuttons,that'swhywechosehere

adialogwithoutbuttons.

FindtheLabelinthelistintheleftpanel,anddragitontothecanvasofourwidget.

Double-clicktherecentplacedLabel,andchangeitstexttoLength.

Right-clickthewidgetcanvas,andchooseLayout->LayoutinaGrid.Thiswillturn

ourwidgetintoagridwithcurrentlyonlyonecell,occupiedbyourfirstlabel.Wecannow

addthenextitemsattheleft,right,toporbottomofourfirstlabel,andthegridwil

lexpandautomatically.

Addtwomorelabelsbelowthefirstone,andchangetheirtexttoWidthandHeight:

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Nowplace3DoubleSpinBoxwidgetsnexttoourLength,WidthandHeightlabels.For

eachofthem,inthelowerleftpanel,whichshowsalltheavailablesettingsforthe

selectedwidget,locateSuffixandsettheirsuffixtomm.FreeCADhasamore

advancedwidget,thatcanhandledifferentunits,butthatisnotavailableinQtCreator

bydefault(butcanbecompiled),sofornowwewilluseastandardDoubleSpinBox,

andweaddthe"mm"suffixtomakesuretheuserknowsinwhichunitstheywork:

Nowourwidgetisdone,wejustneedtomakesureofonelastthing.SinceFreeCAD

willneedtoaccessthatwidgetandreadtheLength,WidthandHeightvalues,weneed

togivepropernamestothosewidgets,sowecaneasilyretrivethemfromwithin

FreeCAD.ClickeachoftheDoubleSpinBoxes,andintheupperrightwindow,double-

clicktheirObjectName,andchangethemtosomethingeasytoremember,forexample:

BoxLength,BoxWidthandBoxHeight:

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Savethefile,youcannowcloseQtCreator,therestwillbedoneinPython.

OpenFreeCADandcreateanewmacrofrommenuMacro->Macros->Create

Pastethefollowingcode.Makesureyouchangethefilepathtomatchwhereyousaved

the.uifilecreatedinQtCreator:

importFreeCAD,FreeCADGui,Part

#CHANGETHELINEBELOW

path_to_ui="C:\Users\yorik\Documents\dialog.ui"

classBoxTaskPanel:

def__init__(self):

#thiswillcreateaQtwidgetfromouruifile

self.form=FreeCADGui.PySideUic.loadUi(path_to_ui)

defaccept(self):

length=self.form.BoxLength.value()

width=self.form.BoxWidth.value()

height=self.form.BoxHeight.value()

if(length==0)or(width==0)or(height==0):

print("Error!Noneofthevaluescanbe0!")

#webailoutwithoutdoinganything

return

box=Part.makeBox(length,width,height)

Part.show(box)

FreeCADGui.Control.closeDialog()

panel=BoxTaskPanel()

FreeCADGui.Control.showDialog(panel)

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In the code above, we used a convenience function (PySideUic.loadUi) from the

FreeCADGuimodule.Thatfunction loadsa.uifile,creates aQtWidgetfrom it,andmaps

names,sowecaneasilyaccessthesubwidgetbytheirnames(ex:self.form.BoxLength).

The"accept"functionisalsoaconvenienceofferedbyQt.Whenthereisa"OK"buttonina

dialog (which is the case by default when using the FreeCAD Tasks panel), any funcion

named"accept"willautomaticallybeexecutedwhenthe"OK"buttonispressed.Similarily,

you can also add a "reject" function which gets executed when the "Cancel" button is

pressed. In our case, we ommitted that function, so pressing "Cancel" will do the default

behaviour(donothingandclosethedialog).

Ifweimplementanyoftheacceptorrejectfunctions,theirdefaultbehaviour(donothingand

close)willnotoccuranymore.SoweneedtoclosetheTaskpanelourselves.Thisisdone

with:

FreeCADGui.Control.closeDialog()

Oncewe haveour BoxTaskPanelthat has1) awidget called"self.form" and2) ifneeded,

acceptandrejectfunctions,wecanopenthetaskpanelwithit,whichisdonewiththesetwo

lastlines:

panel=BoxTaskPanel()

FreeCADGui.Control.showDialog(panel)

NotethatthewidgetcreatedbyPySideUic.loadUiisnotspecifictoFreeCAD,itisastandard

Qt widget which can be used with other Qt tools. For example, we could have shown a

separate dialog box with it. Try this in the Python Console of FreeCAD (using the correct

pathtoyour.uifileofcourse):

fromPySideimportQtGui

w=FreeCADGui.PySideUic.loadUi("C:\Users\yorik\Documents\dialog.ui")

w.show()

Ofcoursewedidn'taddany"OK"or"Cancel"buttontoourdialog,sinceitwasmadetobe

used from the FreeCAD Task panel, which already provides such buttons. So there is no

way to close the dialog (other than pressing its Window Close button). But the function

show()creates anon-modal dialog,which meansit doesn'tblock therest ofthe interface.

So,whileourdialogisstillopen,wecanreadthevaluesofthefields:

w.BoxHeight.value()

Thisisveryusefulfortesting.

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177

Finally, don't forget there is much more documentation about using Qt widgets on the

FreeCADWiki, inthePythonScripting section, which contains a dialog creation tutorial, a

special3-partPySidetutorialthatcoversthesubjectextensively.

Readmore

QtCreator:https://en.wikipedia.org/wiki/Qt_Creator

InstallingQtCreator:https://www.qt.io/ide/

Pythonscriptingdocumentation:http://www.freecadweb.org/wiki/index.php?

title=Power_users_hub

Dialogcreationtutorial:http://www.freecadweb.org/wiki/index.php?title=Dialog_creation

PySidetutorials:http://www.freecadweb.org/wiki/index.php?title=PySide

PySidedocumentation:http://srinikom.github.io/pyside-docs/index.html

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178

TheCommunity

Nomanualdealingwithfreeandopen-sourcesoftwarewouldbecompletewithoutachapter

about the community. As the vast majority of free and open-source software projects,

FreeCAD is made by a community, and maintained by that community. Instead of the

opaque,unknown, impersonaland inaccessable firmthat ismore than oftenfound behind

commercialsoftware,freeandopen-sourcesoftwarecommunitiesareopenspaces,where

youasauserarewelcome,andwhereyoucangetanswersveryfast,andevenhaveyour

sayinthedevelopmentofthesoftwareitself.Youarealsomorethanwelcometohelp,there

aretasksforeverybody.

Thecommunityisagrowing,eclecticgroupofallkindsofpeopleunitedbytheirpassionfor

FreeCAD.AllworkonFreeCADvoluntarily,duringtheirfreetime(althoughsometimesfirms

orindividualsgathertopayacoupleofprogramminghourstoadevelopertoimplementa

specificfunction).Someareprofessionalprogrammers,somearelong-timeFreeCADusers

(someofthemaretrueFreeCADgurus,whoknowalmosteverything,andmanyofthemend

upknowingalotaboutFreeCADprogrammingtoo),andmanyarenewusersofFreeCAD.

Thereisnothingspecifictodotobepartofthecommunity.JustuseFreeCAD!

ThemainplacewherethecommunitymeetsanddiscussesistheFreeCADforum.Allyou

needtodotoparticipatetothediscussionsistoregisteranaccountontheforum(Yourfirst

post will need to be approved by a moderator before you can post more, to prevent

spamming). The forum is a great place to ask questions when you are new to FreeCAD.

Providedyoumadeagoodquestion(besuretoreadtheforumrulesastheycontainuseful

informationtoturnyourquestionintoagoodquestion),youwillusuallygetseveralreplies

withinthesamehour.Ifyouthinksomeonemighthaveaskedyourquestionalready,besure

tosearch,youranswermightalreadybethere.

The forum is also a great place to show what you achieved with FreeCAD, to help

newcomerswhenyouaremoreexperienced,andtofollowandgiveyouropinionsinmore

technicaldiscussionsaboutdevelopment.AlltheFreeCADdevelopmentisdiscussedonthe

forum,andanybodyisfreetoreadorparticipate.

TherearealsoFreeCADcommunitiesformingoutsideoftheFreeCADforum,forexample

onFacebookorGoogle+.

IfyouarebecomingasenthusiasticaboutFreeCADasweare,youmightwanttohelpthe

project. This can be done in many different ways, and there are tasks for everybody,

programmersandnon-programmers,forexample:

Helptospreadtheword:Manypeoplewouldgethugebenefitfromusingafree,open-

Thecommunity

179

source3DmodelerlikeFreeCAD,butsimplydon'tknowitsexistence.Publishingthe

workyoudowithFreeCAD,talkingaboutitonsocialnetworks,etc...helpsthesepeople

todiscoverFreeCAD.

Helpnewcomers:Thevastmajorityofdiscussionsontheforumarequestionsasked

bynewusers.Youmightknowgoodanwerstogivethem.

Helpreportingbugs:ThestablilityofFreeCADcomesinlargepartfromthefixingof

bugs.SinceitisnotpossiblefortheFreeCADdeveloperstotestallpossibleusecases,

itisimportantthatusersreportproblemswhentheydetectthem.Besuretoreadthe

guidelinesifyouthinkyoufoundabug,andthenwriteareportonthebugtracker.

Helptowritedocumentation:TheFreeCADdocumentationwikiisalsowrittenby

communitymembers.Somesectionsofitarestillincomplete,ortheirinformation

incorrectorobsolete.Youmightbeabletohelptofixthat.Tobeabletoworkonthe

wiki,youwillneedtofamiliarizeyourselfwithwikiediting,andaskpermissiontoeditthe

FreeCADwikiontheforum.

HelptotranslateFreeCAD:ThetranslationofFreeCADisdoneonlinebycommunity

members,oncrowdin.Ifyoudon'tseeyourlanguagethere,askoneofthe

administratorstohaveitadded.

Helptotranslatethewikidocumentation:Everypageofthewikiistranslatable,and

requiresverylittleknowledgeofthewikisyntax.Helpingwithtranslationisalsoagreat

waytolearnFreeCAD.

Writescriptsandmacros:FreeCADhasagrowinglistofMacros.Ifyouwrotesome

interestingfunctionality,considersharingitthere.

Programming:Forthis,youneedtoknowhowtoprograminPythonorC++,andhave

agoodknowledgeofFreeCADitself.

The source code of FreeCAD is located on the Github account of the FreeCAD project.

Anybodycan download, useand modifythe code. You canpublish your modifications(on

GithuboranyotherGithostingservice).Ifyoumadeinterestingmodifications,thatyouwish

to see included in the FreeCAD source code, you must ask the community to have them

included.ThiscanbedoneusingGithub'spullrequestsmechanism,buttheverybestwayis

todiscusswhatyouintendtodofirstontheforum,andthenpostanofficialrequestinthe

Pullrequests sectionof the forumwhen your codeis ready. This avoidsthat you workon

somethingthatsomeoneelseisalreadyworkingontoo,andensuresthatothersagreewith

thewayyouaredoingit,sothereisnoriskofhavingyourworkrefusedforsomereasonyou

didn'tforesee.

Hopefully, wemanaged togive youa goodtaste of FreeCADin thismanual, andyou are

alreadyournewestcommunitymember.Welcome!

Readmore

TheFreeCADforum:http://forum.freecadweb.org

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180

ThesourcecodeofFreeCAD:https://github.com/FreeCAD/FreeCAD

TheFacebookFreeCADcommunity:https://www.facebook.com/FreeCAD

TheGoogle+FreeCADcommunity:

https://plus.google.com/u/0/communities/103183769032333474646

TheFreeCADdocumentationwiki:http://www.freecadweb.org/wiki

TranslatingFreeCADoncrowdin:https://crowdin.com/project/freecad

TheFreeCADbugtracker:http://www.freecadweb.org/tracker

Thecommunity

181

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