Linear Structures Workflow Guide

User Manual:

Open the PDF directly: View PDF .
Page Count: 54

Autodesk

Global Consulting Delivery

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 1 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Executive Summary

This document is the guide to using the Autodesk Model Authoring process for Linear Structures which includes

the Dynamo CivilConnection and CivilPython technology packages as workflow enablers.

We define a linear structure as being any object either defined by a relationship with an alignment/profile or

discretely placed at a location that can be defined by a positional relationship with the alignment/profile for a road

or railway. Typically, these are tunnels and bridges, but could also be foundations for a gantry or a retaining wall

for waterways or pipelines.

Implementing this workflow facilitates efficient model information exchange for Linear Structures designs. The

benefits of this workflows are:

• Reduced time to manage design updates, avoiding manual rework and reducing the resources needed.

• Improved collaboration, connecting the models in real-time.

• Improved coordination, reducing the risks of out-of-date models and increasing model accuracy.

• Gaining advantage on the market modelling complex geometry and systems that are very difficult or

impossible to do with the interactive tools out-of-the-box.

• Achieving a higher return on the investment, using the appropriate tools in an organized workflow.

This document covers the roles involved in the Linear Structures workflow, their responsibilities in the process and

how they should collaborate and communicate.

The technology section provides a guide on how to prepare the tools, setup the design and manage model updates.

The CivilConnection package is the technology that enables an efficient model authoring process for Linear

Structures using Civil 3D and Revit.

CivilPython is a command for Civil 3D that allows to run Python scripts for Civil 3D. The scripts can access the

product .NET framework providing the flexibility of a scripting environment but without the overhead of compiling

the code.

In the last section of the document there is a list of the nodes contained in the current version of the CivilConnection

package with a brief description of their functionality.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 2 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Contents

Executive Summary .............................................................................................................................................. 1

1 Introduction .................................................................................................................................................... 4

2 People ............................................................................................................................................................. 5

2.1 Roles and Responsibilities ......................................................................................................................... 5

2.2 Collaboration .............................................................................................................................................. 6

2.3 Communication .......................................................................................................................................... 7

3 Process ........................................................................................................................................................... 8

3.1 Tasks Description .................................................................................................................................... 10

3.2 BIM Uses ................................................................................................................................................. 19

4 Technology ................................................................................................................................................... 21

4.1 IT Requirements ...................................................................................................................................... 21

4.2 CivilConnection ........................................................................................................................................ 26

4.3 CivilPython ............................................................................................................................................... 44

CivilConnection Snippets ................................................................................................................................... 47

CivilConnection Nodes Quick Reference .......................................................................................................... 51

Document Control ............................................................................................................................................... 52

List of figures

Figure 1: Collaboration map example on a tunnel linear asset ............................................................................... 9

Figure 2: Volume definitions along an asset as illustrated in Figure 11 PAS 1192-2:2013 ................................... 10

Figure 3: Linear Assets Collaboration Map Template ........................................................................................... 11

Figure 4: Define and use a Unique Reference System file for Shared Coordinates in Revit ................................. 14

Figure 5: Define the target category for the IfcBuildingElementProxy class in the IFC ......................................... 15

Figure 6: Setup and Update an IFC link ................................................................................................................ 16

Figure 7: Publishing Shared Site to a Revit link instance ...................................................................................... 16

Figure 8: Manage Node and Package Paths ........................................................................................................ 27

Figure 9: Add new package paths to Dynamo settings ......................................................................................... 28

Figure 10: Civil 3D Workspace .............................................................................................................................. 28

Figure 11: Civil 3D Coordinate System ................................................................................................................. 29

Figure 12: Set Revit length units ........................................................................................................................... 29

Figure 13: CivilConnection in the Dynamo library ................................................................................................. 30

Figure 14: Access the Geometry Working Range in Dynamo ............................................................................... 31

Figure 15: Set the working range to Medium ........................................................................................................ 31

Figure 16: Point Codes in the Subassembly Composer ........................................................................................ 32

Figure 17: Civil 3D 2017 Property Sets on 3D Solids ............................................................................................ 33

Figure 18: IFC Import Settings .............................................................................................................................. 34

Figure 19: Example spreadsheet containing MEP Family selection and location parameters .............................. 39

Figure 20: Value error via Revit User Interface ..................................................................................................... 41

Figure 21: Change values via Dynamo ................................................................................................................. 42

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 3 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 22: Conflict loading the CivilConnection 2018 in Revit 2017 ...................................................................... 43

Figure 23: The CivilConnection 2018 cannot connect to Civil 3D 2017 ................................................................. 43

Figure 24: Correct settings for the shortcut target ................................................................................................. 44

Figure 25: Excerpt of the script dumping Civil 3D Property Sets to a CSV file ...................................................... 45

Figure 26: Excerpt of the script populating Civil 3D Property Sets on objects reading from a CSV file ................. 46

Figure 27: CivilApplication ..................................................................................................................................... 47

Figure 28: GetDocuments ..................................................................................................................................... 48

Figure 29: GetCorridors ........................................................................................................................................ 48

Figure 30: GetCodes ............................................................................................................................................. 49

Figure 31: GetFeaturelinesByCode ....................................................................................................................... 50

List of tables

Table 1: Linear Structures Model Authoring RACI Matrix ........................................................................................ 5

Table 2: Revit 2017 IT Requirements .................................................................................................................... 21

Table 3: Revit 2018 IT Requirements .................................................................................................................... 22

Table 4: Revit 2019 IT Requirements .................................................................................................................... 22

Table 5: Revit 2020 IT Requirements .................................................................................................................... 23

Table 6: Civil 3D 2017 IT Requirements ............................................................................................................... 24

Table 7: Civil 3D 2018 IT Requirements ............................................................................................................... 24

Table 8: Civil 3D 2019 IT Requirements ............................................................................................................... 25

Table 9: Civil 3D 2020 IT Requirements ............................................................................................................... 25

Table 10: CivilConnection Shared Parameters ..................................................................................................... 35

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 4 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

1 Introduction

The outcome of the Linear Structures BIM workflow is to establish a common language across multiple disciplines

involved in the design of linear assets, such as roads, tunnels and railways. This enables collaboration and

coordination of both the geometric and information models, reducing the effort needed to manage model changes.

The basic components of this common language are:

• Linear Coordinate Systems, which are used in linear infrastructures to describe the assets in space

using a set of linear coordinates (station, offset and elevation) rather than the more common X, Y, Z

coordinates in the Cartesian space.

• Lean Workflows, for which the ownership of model elements is explicitly defined so that there is no

duplication of work among disciplines. The modelling strategy uses the right tools for the right purpose to

maximize efficiency and reduce waste to a minimum. In this context, “waste” is the need for remodeling

something that has been other in a different platform with the connected risks of misinterpretation,

discrepancy and omissions.

• Interoperability, where the information contained in the different models is accessible to the other

disciplines and model authoring platforms. The models are correlated through a set of dynamic

relationships based on information rather than data. The PAS 1192-2: 2013 defines information as the

representation of data in a formal manner suitable for communication, interpretation or processing by

human beings or computer applications. The same norm defines data as information stored but not yet

interpreted or analyzed (for example a digital file).

The proposed solution is structured using the typical factors of successful technology implementation:

• People

• Process

• Technology

CivilConnection is a package for Dynamo for Revit that connects Revit and Civil 3D. The package enables

prototyping and interoperability between the two modeling environments.

CivilPython is a command for Civil 3D that allows to run Python scripts for Civil 3D. The scripts can access the

product .NET framework providing the flexibility of a scripting environment but without the overhead of compiling

the code.

Autodesk Consulting has developed these technology packages to support the Linear Structures Model Authoring

workflow.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 5 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

2 People

In using this framework of people, process, and technology, it is acknowledged that no matter how good technology

is and the processes that it may automate, without people engaged with the technology, understanding the daily

data requirements and adopting the process, the technology will not function.

Increasingly, national codes define the roles and responsibilities among design partnerships for authoring, sharing,

and validating the quality of information modeling received. But as new tools such as Dynamo appear, RACI

matrices need more tasks.

Despite the complexity that this seems to add, the solution simplifies collaboration by automating information format

conversion between applications that consume diverse data and facilitates communication amongst the design

parties by making that data transfer transparent.

2.1 Roles and Responsibilities

Role names in this document follow PAS1192-2:2013 guidance (link

). The table below extends “Table 2 –

Information exchange activities” in PAS1192, where section 7.5.1.6 says:

For successful information management exchange the following activities listed in Table 2

shall be undertaken at all stages of a project.

The roles involved in this process are the same as those defined in a task team for each discipline involved. The

responsibilities concerning the ownership and hierarchy of the model elements are defined on a project basis in

the BIM Execution Plan. The roles can be aspects of a person’s job. A role may be performed by more than one

person and a single person may act in more than one role. This is left to the project team’s discretion but should

be agreed at the outset.

Once the matrix of Model Element Authors has been defined for a linear structure type, the roles involved should

collaborate among disciplines to define the common references and interface protocols throughout the project

lifecycle.

The following RACI matrix defines the different degrees of involvement of the typical roles in a task team.

• Responsible (R)

• Accountable (A)

• Consulted (C)

• Informed (I)

For more info on defining RACI and the model see http://racichart.org/the-raci-model/

Table 1: Linear Structures Model Authoring RACI Matrix

Activities

Project

Information

Manager

Project

Delivery

Manager

Lead

Designer

Task

Team

Manager

Task

Information

Manager

Interface

Manager

Information

Originator

Define model elements

ownership

Select technology systems

to author the model

elements

http://bim-level2.org/en/standards/ Accessed June 2018

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 6 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Activities

Project

Information

Manager

Project

Delivery

Manager

Lead

Designer

Task

Team

Manager

Task

Information

Manager

Interface

Manager

Information

Originator

Define point codes naming

convention

Define BIM Uses

requirements to implement

in the project

Define Model Authoring

strategy for the task-based

Civil 3D models

Set up dynamic

relationships between

inputs and Civil 3D models

Assign information via

property sets (*)

Set up Revit model Shared

Coordinates

Link IFC in Revit and

publish Shared

Coordinates (*)

Set up task-based dynamic

relationships between Civil

3D and Revit via Dynamo

Add or Subtract solids to

the corridor geometries for

coordination and detailing

(*)

Create Revit families of

continuous elements

Detail modelling of

continuous elements

Manage model

coordination and update

inputs

Prepare the models for

issue and enable other BIM

Uses

The tasks with a (*) may depend on the information requirements for the project.

See the tasks description in this document.

2.2 Collaboration

The information exchange is possible only if there is a collaboration framework in place. Design data should be

easily accessible to all the teams via a common data environment with a clear understanding of who may use the

data and for what purpose.

Collaboration is crucial for BIM because it reduces the risk of inconsistencies and mistakes. According to PAS

1192-2:2013 the definition of Level 2 BIM will continue to evolve around the core principle of the shared use of

individually authored models in a common data environment. The scope of Level 2 BIM workflows is the production

of coordinated design and construction information. The information models are usually exchanged in some form

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 7 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

of data on a periodic base, for example federated models are exchanged for spatial coordination and review,

drawing sheets are issued for information as well as specifications for systems, elements and materials, etc. This

means the information contained in the models is captured in some format to support this exchange outside the

model authoring environments. Data must then be reinterpreted by the stakeholders to check the design content

and coordination. The interpretation is not effortless, it can cause mistakes and omissions and ultimately fail to

produce coordinated information models. The quality of the coordination of the information models in a collaborative

environment over time depends on the skills of the individuals and the effectiveness of the communication of design

changes. This can be achieved if there is clarity around the information structure and if the data interpretation is

simplified or even automated. In principle, the more frequently the information is exchanged the better coordinated

the discipline models will be. In practice, because of the coordination workflow limitations and because of the lack

of automated interpretation of the data, a change of a small entity in one discipline has the same impact of a change

of much more significance when updating models. To limit the costs of modeling, coordination exchanges are

restricted to the minimum necessary, but this does not really address the real problem which is, managing the

model updates efficiently.

One of the main goals of the Linear Structures workflow is to improve and simplify the collaboration process by:

• Reducing the effort of interpreting data: Defining a common language for Linear Structures across

disciplines, giving a common understanding of linear coordinate systems defined by stations, offset and

elevation. Involving all disciplines in the creation of the necessary tools to enable an efficient modeling

process (I.e. point codes naming convention per discipline on Civil 3D subassemblies).

• Managing model updates efficiently: Defining dynamic relationships to control model elements. Using

Dynamo to establish these logical relationships and capture the results in Revit and Civil 3D.

The information contained in the different model authoring environments becomes consistent and relevant. The

model elements are clearly assigned reducing the risk of inconsistencies. Thanks to the dynamic relationships the

model elements are connect to the information model that is driving them hierarchically.

2.3 Communication

Design teams should be able to communicate design changes and resolutions to coordinate model conflicts.

Effective communication can significantly improve the coordination process. Raising the awareness of the current

status of the design in a team should become a best practice in an agile, multi-disciplinary design environment.

Identifying all the changes that occurred between two coordination meetings is not always an easy task.

The communication among task teams starts at the very beginning of the design and continues through the work

stages. Disciplines should bring their requirements to define the necessary dynamic relationships to enable efficient

model management. For example, a naming convention for point codes, and therefore corridor feature lines, can

simplify the interpretation of the design data. It’s most beneficial to identify the key linear references across teams.

The Linear Structures workflow is based on the principle of data-transparency: all the task teams can have access

to the latest information models of other disciplines. The latest information can be used to update their own design

models or to communicate design intentions more effectively (e.g. the MEP engineer can place Placeholder solids

for openings in a concrete wall for the structural engineer to review).

In this workflow, there is less needing to request the latest information in a useable, published format from the other

disciplines. Nevertheless, a proactive approach to communication it is still the best option.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 8 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

3 Process

This process describes how to connect information models between Civil 3D and Revit, managing design updates

based on linear coordinate systems, using Dynamo to automate the workflow and maintain the dynamic

relationships between the model authoring environments.

Implementing this workflow facilitates efficient model information exchange for Linear Structures designs. The

benefits of this workflow are:

• Reduced time to manage design updates, avoiding manual rework and reducing the resources needed.

• Improved collaboration, connecting the models in real-time

• Improved coordination, reducing the risks of out-of-date models and increasing model accuracy.

• Gaining advantage on the market modelling complex geometry and systems that are very difficult or

impossible to do with the interactive tools out-of-the-box.

• Achieving a higher return on the investment, using the appropriate tools in an organized framework.

There are many possible entry points for this process, the common milestone is, as a minimum, a Civil 3D model

containing at least a corridor or an alignment with vertical profiles. The main goal is to enable a mechanism that

allows Civil 3D to update the model almost in real time. This is achieved by setting up the data shortcut in Civil 3D

and leveraging dynamic input updates (e.g. LandXML for alignments, surface and linear targets, etc.).

The next step is to define the dynamic relationships in the linear coordinate systems that describe the asset, in

other words to define the volumes along the asset.

In Civil 3D, this is done using the assemblies (the parametric components that define a linear asset cross-section),

the regions (the segments along the linear asset in which a given cross-section is applied to) and the targets (the

entity and constraints that enable the control of the linear asset overall geometry, e.g. surfaces, alignments, vertical

profiles, feature lines, and polylines). Each assembly is assigned to a region in the asset. Where this division occurs

is part of the modeling strategy that should be determined by design process, work breakdown and enabling

downstream BIM uses. Assemblies are positioned and maintained by Civil 3D according to the frequency settings

in a corridor.

Each assembly carries the information of the subassemblies, these are in turn defined by a set of points with a

code associated. The sequence of points with the same codes along the asset is used to create a string in the

space that is uniquely identified as a feature line. Every two points in a subassembly define a link, the links are

used to generate surfaces along the corridor. Each closed loop of links in a subassembly defines a shape that is

used to generate solids along the corridor.

Feature lines define the linear coordinate systems that can be used to build dynamic relationships with other objects

maintained via CivilConnection and Dynamo.

These relationships can be stored in Revit using shared parameters, stored on Civil 3D objects or serialized in an

spreadsheet, XML or similar.

When a change to the configuration of the linear coordinate systems is introduced, the design will update

recalculating the values of the dynamic relationships and updating the model in Civil 3D and Revit via Dynamo

CivilConnection.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 9 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 1: Collaboration map example on a tunnel linear asset

Structure

Transportation Architecture

MEP

Hydraulic

Geology

Survey

Outside

Tunnel

Inside

Tunnel

Inside

Tunnel

Outside

Tunnel

Civil 3D

Revit

• Electrical

• Piping

• Ventilation

• Shafts

• Drainage

• Fire Escape

• Utility Rooms

• Landscaping

• Plants

• Alignment

• Profiles

• Roadway

• Earthworks

• Tunnel

• Barriers

• Fire Resistance

• Lining System

Dynamo

CivilConnection

CivilPython

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 10 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 2: Volume definitions along an asset as illustrated in Figure 11 PAS 1192-2:2013

3.1 Tasks Description

This section describes the key tasks in Table 1, Linear Structures Model Authoring RACI Matrix.

Define model elements ownership

At the beginning of a project, the task teams (i.e. discipline teams) list the real elements that needs to be defined

for a given linear asset. In doing so, the elements are grouped by task team ownership to avoid data redundancy.

The teams also underline the dependencies relationships between objects: this defines the elements and teams’

hierarchy and will be used to guide the information exchange and capturing the dynamic relationships to drive the

model elements. The result of this task is captured in the collaboration map: the number of elements and

information pertaining a task team defines the size of the team circle, but the hierarchy is derived from the object

relationships within the same disciplines and towards other disciplines.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 11 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 3: Linear Assets Collaboration Map Template

Select technology systems to author the model elements

Depending on the nature of the objects (continuous vs. discrete, linear vs. point) the project teams select the best

model authoring tools to model them. In general, Civil 3D is used to define the continuous/linear objects and

references (i.e. alignment and corridor feature lines) whilst Revit is used for discrete objects. Dynamo is used to

capture the intelligence that defines the objects relationships, create objects that would be otherwise difficult to

manage with Revit or Civil 3D only (i.e. openings along a tunnel wall, equipment along a feature line).

Define point codes naming convention

Point codes are used by Civil 3D to generate corridor feature lines. Without corridor feature lines, the Linear

Structures workflow is limited to the corridor baselines and there is not enough information to mimic the Revit

hosting capabilities. In a subassembly, there are potentially many point codes and each assembly can be

composed by several subassemblies. In turn, each region in a corridor can have as many feature lines and each

baseline can have multiple regions. Furthermore, a corridor can have multiple baselines, so the number of feature

lines and associated point codes can be difficult to manage. Without a clear, consistent and effective naming

convention for the point codes becomes difficult communicating the design intent and leverage the automation

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 12 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

across multiple disciplines. A good naming convention defines a clear syntax and style, here are some

recommendations:

• Using underscores to separate words.

• Start a word with an upper case.

• Do not use abbreviations if not agreed in the BIM Execution Plan.

• Describe the object following a granularity principle (i.e. Assembly_element_subelement_vertical

location_horizontal location).

For example:

• Tunnel_ Wall1_Base_External

• Bridge_Deck_Top_Left

Whenever possible it is recommended to use the same Civil 3D Subassembly point code to represent a continuous

edge in the model across multiple regions. Point codes enable the Linear Structures workflow for all disciplines and

the naming convention should be part of the BIM Execution Plan.

Note that in CivilConnection a feature line is defined on a Civil 3D Corridor as opposed to a Land Feature Line that

is instead defined without the need for a corridor. A Feature Line in CivilConnection is always defined per baseline

region as opposed to an Auto Corridor Feature Lines in Civil 3D that can be joined across multiple baseline regions.

Define BIM Use requirements to implement in the project

Each BIM Use can affect the standard methods and procedures used to author the models. The requirements that

are necessary to enable the BIM Uses should be captured in the BIM Execution Plan and be mandatory for the

project team and the supply chain. The Project Information Manager is responsible for the definition of such

requirements as they impact on all disciplines, on the organization of the models and associated data.

Define Model Authoring strategy for the task-based Civil 3D models

The model is organised to maximise performance and enable the project BIM Uses. This has a direct impact on

how the disciplines are collaborating and coordinating the information models in the Linear Structures workflow.

The strategy adopted to build the Civil 3D models should be defined in the BIM Execution Plan. The point codes

discussion above is a part of this strategy, but work breakdown and model breakdown plans need to be developed

in order to maintain optimal performance of the model, the workflow and the team. This will include where to divide

corridors and regions, responsibilities for areas of the model and how dynamic links between model elements will

be built in order that when changes are made, the impact is obvious.

Model breakdown across linear project sites should be carefully considered and communicated into the Revit

shared coordinate system process as outlined below.

Set up dynamic relationships between inputs and Civil 3D models

Civil 3D offers a set of tools to facilitate the creation and management of the models so that they are dynamically

linked to the inputs. Adopting offset alignments, targets, extracting corridor feature lines, enable a safe workflow in

Civil 3D throughout the duration of the design cycle because ensure the models to be up-to-date with the latest

input regardless the complexity or the discipline. The inputs for a Civil 3D corridor can be LandXML or GENIO files,

2D DWGs, and even other Civil 3D corridor models. The crucial aspect is to identify the best methodology to update

the Civil 3D corridor definitions when a change in the inputs should occur. The recommendation is to use an

approach that raises the awareness with the user that a change happened and that provides an easy way to trigger

the necessary updates is the user wish to do so.

One of the methodologies that is present natively in Civil 3D regards the data shortcuts.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 13 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

This feature enables an effective collaboration across several Civil 3D models improving the performance and

preserving the dynamic links with the inputs. Data short cuts should be defined in the BIM Execution Plan.

Since Civil 3D 2017 the objects suitable for shared references via data short cuts are surfaces, alignments and

associated profiles and corridors. See further references on Data Shortcuts.

Assign information via property sets

A property set is a collection of parameters that can be applied to an instance of an AutoCAD object. The definition

of the property set contains also the type of objects it is applicable to. Setting the Civil 3D system variable

AECPSDAUTOATTACH to 1 it is possible to assign the property sets automatically to all the objects of the same

type. See further references for property sets.

Since Civil 3D 2017 it is possible to expand and maintain the property sets on corridor solids at the moment of their

extraction. The information contained in the property sets contributes to fulfil the EIRs and AIRs. It is important not

to lose the information attached throughout the process regardless of the authoring platform.

Civil 3D exposes the property sets via the STYLEMANAGER command and they can be transferred between

projects via the Design Centre. Property sets are customizable, and they support different kinds of value types,

texts, numbers and even enumerations or lists. The values can be dynamically calculated using formulae or reading

other properties from the objects.

Set up Revit model Shared Coordinates

Revit is used in each discipline to model or capture the discrete elements in a linear asset. The Revit model must

acquire the coordinates so that the local origin is close to the location of the linear asset in the World Coordinate

System used in Civil 3D. This impacts how precisely the geometry of the corridor solids will be when using the IFC

export workflow, the closer the better. There are several ways to setup the shared coordinates system in a Revit

model. Autodesk recommend definition of a Unique Reference System (URS) file that is used across multiple

disciplines. Due to the Linear Structures typical project geographical extents, it is entirely possible that every asset

in the project will need to have its own URS file or at least its own shared site. The following diagram shows how

to create and use a URS file to acquire the shared coordinates from. The Project Information Manager is

responsible for the creation and maintenance of the URS files at a project level. In the Task Team, the Information

Originator is responsible for using the correct URS file for each model. The coordinates used for each asset should

be stored in the BIM Execution Plan. See further references on shared coordinates.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 14 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 4: Define and use a Unique Reference System file for Shared Coordinates in Revit

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 15 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Link IFC in Revit and publish Shared Coordinates (*)

The fastest way to provide the geometry scope and information from Civil 3D and Revit is to use the IFC export of

the Civil 3D corridor solids.

This option is recommended for frequent updates and information exchange. The fast exchange comes with a price

of a tessellated geometry based on the IFC2x3 format that does not support Advanced BRep objects (link).

Even if smooth surfaces were supported, the corridor solids in Civil 3D are defined as unions of profiles rather than

lofts of more than two profiles, therefore they would appear in Revit as segmented at best. For a loft, smooth

transition representation of the corridor solids the reader should refer to the workflow that creates Revit families of

continuous elements. The IFC workflow could still be useful in particularly complex situations such as intersections.

Following some key considerations to enable the IFC export of corridor solids from Civil 3D with CivilConnection.

The corridor solids must be extracted to a clean DWG file to process exclusively the data important for the Linear

Structures workflow. The corridor solids will provide a context to enable other disciplines’ design or to embed linear

modifiers to increase the level of detail in the model. Using IFC allows to retain the geometry and the information

attached to the solids via property sets. The IFC is linked in Revit and converted to unmodifiable Revit objects that

can be used to continue with the design. To export the IFC in the local coordinate system defined in the Revit

model it is necessary to use the CivilConnection package in Dynamo. The following diagrams show the steps to

prepare, setup and updated the IFC link in this workflow.

Figure 5: Define the target category for the IfcBuildingElementProxy class in the IFC

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 16 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 6: Setup and Update an IFC link

Figure 7: Publishing Shared Site to a Revit link instance

Set up dynamic relationships between Civil 3D and Revit via Dynamo

The Information Originator defines the dynamic relationships between the objects in Dynamo and uses the

CivilConnection to process the information contained in the Civil 3D corridors. Dynamo graph development should

be made referring to modelling techniques like use user stories, SIPOC diagrams or task workflows using UML or

BPMN or similar. In this way, it is possible to capture at a high level the functionality and the inputs necessary to

drive the creation of the model elements and provide guidance for their development. The automation requirements

should be captured and clarified with their rationale. Each should have test and fit criteria defined to guide the

development. The requirements must be prioritized and captured in the graph documentation.

Known issues and limitations should also be captured so that users are aware of situations where the graph can

produce unwanted results. This can serve as a starting point for future developments.

When the graph is defined and the logic for an asset in a project is captured it can stay, there is no need to change

it. Dynamo graphs used in previous projects for similar assets can be deployed in new projects. Dynamo graphs

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 17 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

should be optimized to be used via Dynamo Player, a tool available since in Revit 2018.1 that creates a very

simplified interface for the Dynamo graphs inputs and hides the actual complexity with the graph. The set of graphs

is displayed in alphabetical order and this can be used to provide a naming convention that takes care of the

sequence in which each graph should be executed in the project. The users that are not familiar with Dynamo and

the detail of the implementation of each graph can still access the benefits of the automation.

The Revit elements created with CivilConnection will contain a set of shared parameters to enable the common

language around linear structures. For example, an object will carry references such as the corridor name or the

featureline code. These parameters are necessary to enable the update phase of the linear structures’ workflow.

CivilConnection makes sure to capture the GUID of objects created in the Revit model in an XML file to ensure that

the update process is safe and efficient when the Civil input model changes. Only the objects with the shared

parameters for the linear coordinates system compiled are safe to be updated. This enables also a very simple

mechanism to keep track of the changes to a model as the XML stored the name of the project, the user and the

date. The XML file is saved with the Revit model and it is named in the same way. The XML file is structured for

different kinds of objects: single point (i.e. most of the equipment), linear (i.e. pipes, ducts, cable trays, structural

framing, walls, etc.) or multipoint (i.e. adaptive components or floors). CivilConnection creates a new XML

automatically before the user executes the update workflow.

Add or Subtract solids to the corridor geometries for coordination and detailing (*)

CivilConnection enables the creation of discrete elements that would be difficult to model and maintain with Civil

3D only. These objects can be:

• Dynamo geometry environment and then imported in a Civil 3D document (“one-off").

• Revit elements linked into a Civil 3D document (“live link”).

CivilConnection logic is used to create, for example, walls that don’t exactly follow the corridor alignment (i.e. at

the interface between two regions with a different type of applied assembly in a corridor), or to add non-continuous

solids such as retaining walls counterforts.

The same approach can be used to create openings in the corridor solids to improve the coordination, truncate the

corridor for a skewed bridge or to improve the level of detail on the models.

When linking elements, if something changes in the Revit model this will be reflected in the Civil 3D model. If any

of those elements are projected on sections or profiles, the projections will be updated too.

The information can flow from Revit into Civil 3D and remain coordinated over time, this makes Civil 3D an ideal

environment for drawing production in the Linear Structures workflow as it natively provides support for longitudinal

profiles.

Create Revit families of continuous elements

In the design process a time will come when the design of the disciplines with more importance on the hierarchy of

the collaboration map can be considered fixed. The project team can consider the opportunity to further the

modelling and detailing of the continuous elements directly in Revit via CivilConnection. This approach is not

recommended until the drawing production is needed as it can be quite slow compared to the IFC workflow.

The information originator must specify the starting and ending stations for each baseline region as well as the key

stations along the corridor where the continuous elements change suddenly width or height (e.g. recesses,

widening, etc.). For this task it is possible to define a sample line group along the alignment that is used only with

this intent. The goal is to establish pairs of stations along a given baseline region for which is safe to loft multiple

cross-section profiles together without altering the design intent nor the precision of the model.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 18 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

CivilConnection will access the applied subassembly shapes or links in a baseline region of the corridor, extract

the geometry information and use it to create a Revit family with a free form element for each shape in the

subassembly. It is also possible to use a similar approach with geometry for the cross-section profiles that either is

generated in Dynamo or coming from Revit elements (e.g. adaptive components).

This approach comes with several pros:

• The representation of the continuous elements is smooth and not tessellated nor segmented.

• The outcome is a set of Revit families whose geometry can be altered in the Family Editor and adjusted

to accommodate construction detailing.

• The objects can have type, subcategories, materials.

• The objects are updated by CivilConnection, the Element Ids of the instances are preserved, only the

definition of the families is updated.

• The objects can be modified using parts.

• The objects can be used to host free form rebar.

There are also cons to take into consideration:

• The process of creation and update of these families can take quite some time compared to the IFC

workflow.

• Any manual modifications to the families will be lost in case of an update.

• The logic used to create the openings in the IFC workflow needs to be adjusted to target the Revit families

instead.

Detailed modelling of continuous elements

The linear modifiers (e.g. the openings along a tunnel, or skew angles for a bridge deck) have to be transferred

from the IFC workflow and adjusted to target the Revit families as opposed to the DWG solids in Civil 3D. The logic

used to create the tools used in the Boolean operations does not change. It is also possible use alternative detailing

techniques that involve the UI tools available in Revit:

• Edit the family geometry in the family editor with Boolean operations.

• Using parts in the project environment.

• Join and cut geometries with other family instances.

It is also possible to leverage the free form rebar modelling tools that have been introduced and continuously

improved since Revit 2018 onwards (e.g. Free Form Rebar surface based and rebar following a path since Revit

2019.2).

Manage model coordination and update inputs

The multidisciplinary coordination is simplified by adjusting and updating model elements with high accuracy using

an analytical/logical process to modify the linear coordinate systems values. The models update to reflect the

changes in the input discipline design. The effort required to update the models is reduced as the intelligence and

relationships used to drive the model definition is captured in the Dynamo graphs and the outcomes are stored in

the model authoring environments. Is also possible to update the geometries of the discrete Revit elements in Civil

3D as solids and used them in section views or profiles as projections. If the Revit elements should change, the

tools in CivilConnection and CivilPython will update the definitions of the solids in Civil 3D so that the documentation

views in will be updated with the latest discrete elements, preserving for example tags and labels.

Prepare the models for issue and enable other BIM Uses

The design data is authored in the ideal platforms for the type of elements required by the design. The information

is preserved and updated without data duplication or redundancy across platforms. The coordinated information

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 19 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

models can be used to perform the BIM Uses defined in the BIM Execution Plan. The models and documentation

can be shared with the rest of the team for the authorised usage.

3.2 BIM Uses

Using IFC to connect Civil 3D to Revit introduces property sets and values on the objects that remain visible in

Revit. These properties define the linear coordinate system as a common language between the two authoring

platforms.

BIM Uses enabled by this data structure do not stop to Model Authoring: new workflows become possible and

existing workflows become better coordinated requiring less management efforts. Four example BIM uses are

described below but many others are possible by extension or adaptation of the workflow described in this

document.

Drawing production

The shape code assigned in a Civil 3D subassembly can be found as a parameter inside Revit objects after linking

an IFC. This can be used to create view filters in Revit. The view filter creation can be automated in Dynamo and

made available to all the Revit based projects using Transfer Project Standards. Using view filters, the visual

representation of the objects in the structural model can be customized to suit different documentation purposes.

Revit objects can be related to phases in a project and this has an impact on drawing production too. In this

workflow, the corridor objects in Civil 3D become Revit components after linking the IFC and can be associated to

the project phases. For Architecture and MEP disciplines, the plan views rely on Revit linked files, for the length of

the linear structure: it is rarely possible to find a unique horizontal level that encompasses all the objects at the

same time.

In Revit, there are two options to solve this issue: scope boxes or plan regions, neither are very user friendly and

can be difficult to maintain in case of design changes. One easy solution is to implement view filters to turn off slabs

in tunnels and use linked views to show specific levels in the Revit links (i.e. linked utility rooms along a tunnel).

The safest option is still to produce drawings in Civil 3D linking the discrete Revit elements and taking advantage

of the fact that Revit does not support the creation of longitudinal profiles.

3D Coordination

Identifying clashes means to compare models and testing for objects that either occupy the same space or that are

too close to each other. A classification system helps in organizing the clashes and prioritize the resolution actions.

In Linear Structures, using the World Coordinate System is sufficient to identify a clash in space but it is not ideal

in terms of resolution and Design Review because the model is built using a linear coordinate system. This

introduces unnecessary efforts to translate from one system to the other. In the proposed solution, the objects and

clashes can be grouped based on their station, offset and elevation values. The clash results can be related directly

to a portion of the linear structure giving more insights on the clash priorities and restraints to identify the resolution

actions to mitigate the clashes.

In Navisworks it is possible to create search sets using these values and the classification system to organize

Linear Structures models.

The resolution actions can be reflected in the modifications of the station, offset and elevation parameters of the

objects, Dynamo will update the location of the objects accordingly to the new parameter values against the Civil

3D corridor input.

Quantity Take-Off

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 20 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

In buildings, the quantity take-offs are usually referenced to the levels and grid systems, in Linear Structures the

same concept is applied through chainage and cross-sections, to enable this organization, model elements must

contain information on station, offset and elevation.

4D Modelling

To associate a model object to an activity in the task’s hierarchy in a Gantt, a relationship based on a WBS code

is defined. In Linear Structures, the 4D Modelling is once more related to the linear coordinates.

In previous modelling this information was not available on Revit objects. With the proposed workflow, this

information can be used to create the assignment rules in Navisworks to enable, for example, the simulation of

construction fronts of a tunnel or segments of a bridge.

Typically, 4D Modelling for Linear Structures is documented through a space-time diagram: activities are at the

intersection of a specific chainage (column) at a specific time (row). This workflow is enabling a 3D visual

representation of this diagram.

Asset Management

The assets, the utility rooms, the signage, etc. along a Linear Structure are identified using the chainage. It is logical

that the model elements, regardless the platform, must comply with this Asset Information Requirement (AIR) since

the beginning of the project to keep track during the design phase, during the construction and procurement and

later for operation and maintenance.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 21 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

4 Technology

The CivilConnection is compatible with Civil 3D 2017-20, Revit 2017-20 and Dynamo 1.3-2.1.

The 2019 release has been developed specifically against Dynamo 2.0, The 2020 release has been developed

specifically against Dynamo 2.1.

CivilConnection is a package for Dynamo for Revit and needs to be installed locally on a machine or on a shared

network. In case of a network deployment, each Dynamo application on each machine needs configuration to look

for the CivilConnection package.

CivilPython is a set of commands for Civil 3D and needs to be installed locally on a machine. CivilPython leverages

the IronPython engine that comes with Dynamo for Revit, therefore Civil 3D and Revit must be installed on the

same machine. CivilPython contains commands that enable some workflows that are useful for CivilConnection,

therefore CivilPython needs to be installed and approved to use the full range of features present in

CivilConnection.

4.1 IT Requirements

Revit

Table 2: Revit 2017 IT Requirements

Autodesk Revit 2017

Requirements

Operating System

• Microsoft® Windows® 7 SP1 64-bit: Enterprise, Ultimate, Professional, or Home

Premium

• Microsoft® Windows® 8.1 64-bit: Enterprise, Pro, or Windows 8.1

• Microsoft® Windows® 10 64-bit: Enterprise, or Pro

CPU Type

Multi-Core Intel® Xeon®, or i-Series processor or AMD® equivalent with SSE2

technology. Highest affordable CPU speed rating recommended.

Autodesk® Revit® software products will use multiple cores for many tasks, using up

to 16 cores for near-photorealistic rendering operations.

Memory

16 GB RAM

• Usually sufficient for a typical editing session for a single model up to

approximately 700 MB on disk. This estimate is based on internal testing and

customer reports. Individual models will vary in their use of computer resources

and performance characteristics.

• Models created in previous versions of Revit software products may require

more available memory for the one-time upgrade process.

Video Display

1,920 x 1,200 or higher with true color

DPI Display Setting: 150% or less

Video Adapter

DirectX® 11 capable graphics card with Shader Model 5 as recommended by

Autodesk.

Disk Space

• 5 GB free disk space

• 10,000+ RPM (for Point Cloud interactions) or Solid State Drive

Media

Download or installation from DVD9 or USB key

Pointing Device

MS-Mouse or 3Dconnexion® compliant device

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 22 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Autodesk Revit 2017

Requirements

Browser

Microsoft® Internet Explorer® 7.0 (or later)

Connectivity

Internet connection for license registration and prerequisite component download

References

System Requirements for Autodesk Revit 2017 Products

Table 3: Revit 2018 IT Requirements

Autodesk Revit 2018

Requirements

Operating System

• Microsoft® Windows® 7 SP1 64-bit: Enterprise, Ultimate, Professional, or Home

Premium

• Microsoft® Windows® 8.1 64-bit: Enterprise, Pro, or Windows 8.1

• Microsoft® Windows® 10 64-bit:Enterprise, or Pro

CPU Type

Multi-Core Intel® Xeon®, or i-Series processor or AMD® equivalent with SSE2

technology. Highest affordable CPU speed rating recommended.

Autodesk® Revit® software products will use multiple cores for many tasks, using up

to 16 cores for near-photorealistic rendering operations.

Memory

16 GB RAM

• Usually sufficient for a typical editing session for a single model up to

approximately 700 MB on disk. This estimate is based on internal testing and

customer reports. Individual models will vary in their use of computer resources

and performance characteristics.

• Models created in previous versions of Revit software products may require

more available memory for the one-time upgrade process.

Video Display

Ultra-High Definition Monitor

Video Adapter

DirectX 11 capable graphics card with Shader Model 5.

A list of certified cards can be found on the Autodesk Certified Hardware page

Disk Space

• 5 GB free disk space

• 10,000+ RPM (for Point Cloud interactions) or Solid State Drive

Media

Download or installation from DVD9 or USB key

Pointing Device

MS-Mouse or 3Dconnexion® compliant device

Browser

Microsoft® Internet Explorer® 7.0 (or later)

Connectivity

Internet connection for license registration and prerequisite component download

References

System Requirements for Autodesk Revit 2018 Products

Table 4: Revit 2019 IT Requirements

Autodesk Revit 2019

Requirements

Operating System

• Microsoft® Windows® 7 SP1 64-bit: Enterprise, Ultimate, Professional, or Home

Premium

• Microsoft® Windows® 8.1 64-bit: Enterprise, Pro, or Windows 8.1

• Microsoft Windows 10 Anniversary Update 64-bit (version 1607 or higher):

Enterprise, or Pro

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 23 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Autodesk Revit 2019

Requirements

CPU Type

Multi-Core Intel® Xeon®, or i-Series processor or AMD® equivalent with SSE2

technology. Highest affordable CPU speed rating recommended.

Autodesk® Revit® software products will use multiple cores for many tasks, using up

to 16 cores for near-photorealistic rendering operations.

Memory

16 GB RAM

• Usually sufficient for a typical editing session for a single model up to

approximately 700 MB on disk. This estimate is based on internal testing and

customer reports. Individual models will vary in their use of computer resources

and performance characteristics.

• Models created in previous versions of Revit software products may require

more available memory for the one-time upgrade process.

Video Display

Resolutions

Minimum:

1920 x 1200 with true color

Maximum:

Ultra-High (4k) Definition Monitor

Video Adapter

DirectX 11 capable graphics card with Shader Model 5.

A list of certified cards can be found on the Autodesk Certified Hardware page

Disk Space

• 5 GB free disk space

• 10,000+ RPM (for Point Cloud interactions) or Solid State Drive

Media

Download or installation from DVD9 or USB key

Pointing Device

MS-Mouse or 3Dconnexion® compliant device

Browser

Microsoft® Internet Explorer® 7.0 (or later)

Connectivity

Internet connection for license registration and prerequisite component download

References

System Requirements for Autodesk Revit 2019 Products

Table 5: Revit 2020 IT Requirements

Autodesk Revit 2020

Requirements

Operating System

Microsoft® Windows® 10 64-bit

• Windows 10 Enterprise

• Windows 10 Pro

CPU Type

Multi-Core Intel Xeon, or i-Series processor or AMD equivalent with SSE2

technology. Highest affordable CPU speed rating recommended.

Autodesk Revit software products will use multiple cores for many tasks.

Memory

32 GB RAM

• Usually sufficient for a typical editing session for a single model up to

approximately 700 MB on disk. This estimate is based on internal testing and

customer reports. Individual models will vary in their use of computer resources

and performance characteristics.

• Models created in previous versions of Revit software products may require

more available memory for the one-time upgrade process.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 24 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Autodesk Revit 2020

Requirements

Video Display

Resolutions

Minimum:

1920 x 1200 with true color

Maximum:

Ultra-High (4k) Definition Monitor

Video Adapter

DirectX 11 capable graphics card with Shader Model 5.

Disk Space

• 30 GB free disk space

• 10,000+ RPM (for Point Cloud interactions) or Solid State Drive

Media

Download or installation from DVD9 or USB key

Pointing Device

MS-Mouse or 3Dconnexion® compliant device

Browser

Microsoft® Internet Explorer® 10.0 or higher

Connectivity

Internet connection for license registration and prerequisite component download

References

System Requirements for Autodesk Revit 2020 Products

Civil 3D

Table 6: Civil 3D 2017 IT Requirements

Autodesk Civil 3D 2017

Requirements

Operating System

• Microsoft® Windows® 10

• Microsoft Windows 8.1 with Update KB2919355

• Microsoft Windows 7 SP1

CPU Type

1 gigahertz (GHz) or faster 64-bit (x64) processor

Memory

8 GB or greater

Display Resolution

1600x1050 or higher with True Color.

125% Desktop Scaling (120 DPI) or less recommended.

Display Card

1600x1050 or greater True Color video display adapter; 128 MB VRAM or greater;

Pixel Shader 3.0 or greater; Direct3D®-capable workstation class graphics card.

Disk Space

16.0 GB

Browser

Windows Internet Explorer® 9.0 (or later)

Pointing Device

MS-Mouse compliant

Media (DVD)

Download and installation from DVD

Multiple Processors

Supported by the application

.NET Framework

.NET Framework Version 4.6

References

System Requirements Civil 3D 2017

Table 7: Civil 3D 2018 IT Requirements

Autodesk Civil 3D 2018

Requirements

Operating System

• Microsoft® Windows® 10

• Microsoft Windows 8.1 with Update KB2919355

• Microsoft Windows 7 SP1

CPU Type

1 gigahertz (GHz) or faster 64-bit (x64) processor

Memory

8 GB or greater

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 25 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Autodesk Civil 3D 2018

Requirements

Display Resolution

1920 x 1080 with True Color

Display Card

1920 x 1080 or greater True Color video display adapter; 128 MB VRAM or greater;

Pixel Shader 3.0 or greater; Direct3D®-capable workstation class graphics card.

Disk Space

16.0 GB

Browser

Windows Internet Explorer® 11 (or later)

Pointing Device

MS-Mouse compliant

Media (DVD)

Download and installation from DVD

Multiple Processors

Supported by the application

.NET Framework

.NET Framework Version 4.6

References

System Requirements Civil 3D 2018

Table 8: Civil 3D 2019 IT Requirements

Autodesk Civil 3D 2019

Requirements

Operating System

• Microsoft® Windows® 10 Anniversary Update (version 1607 or higher)

• Microsoft Windows 8.1 with Update KB2919355

• Microsoft Windows 7 SP1

Processor

Minimum: 2.5–2.9 GHz or faster processor

Recommended: 3+ GHz or faster processor

Memory

16 GB or more

Display Resolution

Conventional Displays:

1360 x 768 with True Color, and 125% Desktop Scaling (120 DPI) or less

recommended

High Resolution & 4K Displays:

Resolutions up to 3840 x 2160 with True Color (Windows 10 64-bit and capable

display card)

Display Card

1920 x 1080 or greater True Color video display adapter; 128 MB VRAM or greater;

Pixel Shader 3.0 or greater; Direct3D®-capable workstation class graphics card.

Disk Space

16.0 GB

Browser

Minimum: Internet Explorer® 11 or later

Recommended: Google™ Chrome

Pointing Device

MS-Mouse compliant

File Format Changes

AutoCAD .DWG format – R2018

Civil 3D Object format – R2018.2 ¹

¹ New vertical curve profile entities (fixed vertical curve by high or low point) are not

supported in Civil 3D 2018.

.NET Framework

.NET Framework Version 4.7

References

System Requirements Civil 3D 2019

Table 9: Civil 3D 2020 IT Requirements

Autodesk Civil 3D 2020

Requirements

Operating System

• Microsoft® Windows® 7 SP1 with Update KB4019990 (64-bit only)

• Microsoft Windows 8.1 with Update KB2919355 (64-bit only)

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 26 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Autodesk Civil 3D 2020

Requirements

• Microsoft® Windows® 10 (64-bit only) (version 1803 or higher)

Processor

Minimum: 2.5–2.9 GHz or faster processor

Recommended: 3+ GHz or faster processor

Memory

16 GB or more

Display Resolution

Conventional Displays:

1920 x 1080 with True Color

High Resolution & 4K Displays:

Resolutions up to 3840 x 2160 supported on Windows 10, 64 bit systems (with

capable display card)

Display Card

1920 x 1080 or greater True Color video display adapter; 128 MB VRAM or greater;

Pixel Shader 3.0 or greater; Direct3D®-capable workstation class graphics card.

Disk Space

16.0 GB

Browser

Google Chrome (for AutoCAD web app)

Pointing Device

MS-Mouse compliant

File Format Changes

AutoCAD .DWG format – R2018

Civil 3D Object format – R2018.2 ¹

¹ New vertical curve profile entities (fixed vertical curve by high or low point) are not

supported in Civil 3D 2018.

.NET Framework

.NET Framework Version 4.7

References

System Requirements Civil 3D 2020

Dynamo

See Revit requirements.

4.2 CivilConnection

4.2.1 Usage

The CivilConnection package for Dynamo and the CivilPython for Civil 3D are licensed under Apache License,

Version 2.0

You may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on

an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the

License for the specific language governing permissions and limitations under the License.

The project repository is https://github.com/Autodesk/civilconnection

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 27 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

4.2.2 Installation

Copy the folder contained in the Zip file to the default location for Dynamo Revit packages or alternatively to a

custom location on the hard drive or on a shared network path. For a custom location, the path must also be added

in the Dynamo settings. For deployment, the Dynamo Settings XML can be copied on all machines to read form

the same location for the Dynamo packages.

The XML is located in the AppData folder, for Dynamo 1.3:

%APPDATA%\Dynamo\Dynamo Revit\1.3\DynamoSettings.xml

For Dynamo 2.0:

%APPDATA%\Dynamo\Dynamo Revit\2.0\DynamoSettings.xml

In the <CustomPackageFolders> </CustomPackageFolders> node add a <string> </string> node with an inner text

equal to the path to the folder that contains the packages.

Note: After installing CivilConnection in Dynamo for Revit it is necessary to install CivilPython, run it at least once

so that the user authorizes the loading of the necessary assemblies in Civil 3D. See the CivilPython section of this

document for further details.

Figure 8: Manage Node and Package Paths

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 28 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 9: Add new package paths to Dynamo settings

4.2.3 Preparation

This section illustrates some technical features to adopt when using CivilConnection.

Civil 3D

Make sure that Civil 3D is running and at least a document is open. The Workspace must be set to “Civil 3D”. Make

sure to align the drawing units between Civil 3D and Revit (metric or imperial). Make sure that Civil 3D has a single

viewport configuration.

Figure 10: Civil 3D Workspace

In Civil 3D, it is possible to setup the coordinate system to ensure a good interoperability with other software such

as InfraWorks. See further references.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 29 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 11: Civil 3D Coordinate System

Revit

The Dynamo environment will adopt the same units as the Revit document that hosts the Dynamo session. The

CivilApplication node automatically sets the Revit project length units to those in use in the active document in Civil

3D. The user can restore the length units’ settings when using graphs that do not contain CivilConnection nodes.

Figure 12: Set Revit length units

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 30 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Make sure that the Revit document shares coordinates with a Civil 3D document so that the linear asset satisfies

the 20-mile limitation from the start-up position of the project base point.

The recommendation is to create a circle in Civil 3D, centred around the linear asset, if necessary round the

coordinates of the circle centre point via the Properties palette (make sure the World Coordinate System is active).

Select the circle and call the write block command (WBLOCK) to create an empty DWG that contains only the

circle in the same coordinates.

Select the path on the file system where to save the new DWG, keep the units to meters and discard the Map 3D

data.

Once in Revit, activate a plan view and hide all categories (model, annotation) and leave only the Site > Project

Base Point sub-category visible.

Link the newly created DWG in the current view by “Center to Center”.

Acquire the coordinates from the linked DWG.

At the end the Project Base Point reports the same coordinates as the circle in Civil 3D, the Revit file is setup

correctly.

See further references.

Dynamo

Verify that the CivilConnection package is correctly loaded in Dynamo. The AutodeskYYYY shelf will appear in the

library and this will contain the CivilConnection nodes. Ignore the Autodesk shelf that appears immediately above

CivilConnection.

Figure 13: CivilConnection in the Dynamo library

Set the geometry working range to Medium and ignore the warnings associated to these settings during execution.

Changing the settings to other options (i.e. Large or Extra-Large) affects the accuracy in the geometry objects.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 31 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 14: Access the Geometry Working Range in Dynamo

Figure 15: Set the working range to Medium

Note: In Dynamo 2.0 the menu item under Settings has been renamed to Geometry Scaling, but it accesses the

very same Geometry Working Range dialog to select from.

4.2.4 Design Setup

This section illustrates some key features to implement when initializing the design workflow.

Civil 3D

Point Codes

At the beginning of the process each discipline should be aware of the naming convention in place for the point

codes. It is crucial to define the point codes to enable the identification of the key feature lines in a corridor. They

specify the linear coordinate systems necessary to drive the dynamic relationships and manage model updates of

Revit items. The best practice is to define the point codes as input parameters on the subassembly so that it is

possible to apply different naming conventions reusing the same subassemblies in different projects.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 32 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 16: Point Codes in the Subassembly Composer

Property Sets

To produce coordinated information models, it is necessary to manage information and maintain it on the objects

describing a linear asset. Information is a requirement of the BIM Execution Plan to fulfil the Employer Information

Requirements and the Asset Information Requirements. Civil 3D 2017 has introduced a set of dynamically-

maintained property sets on the solids extracted from a corridor. Property sets are safely passed from Civil 3D to

Navisworks and they are also stored when exporting the model to IFC. This is also true for user-defined property

sets. Combined, these features make it possible to migrate geometry and information from Civil 3D to other

platforms, enabling a good level of interoperability. For further references on property sets refer to the CivilPython

section of this document.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 33 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 17: Civil 3D 2017 Property Sets on 3D Solids

IFC

Industry Foundation Classes (IFC) is a non-proprietary data exchange format for BIM workflows. It contains

geometry and information for communicating design intent, in a relatively simple way, among disciplines and model

authoring platforms. In this workflow, IFCs are used to provide an immediate representation of the Civil 3D corridors

in Revit for coordination and collaboration only. At the time of the writing, the IFC 4.1 format supports only the

IfcAlignment class, all other civil objects are not included yet. Civil 3D 2017 supports only the IFC 2x3 format: this

means that the solid elements in a Civil 3D corridor model are classified as IfcBuildingElementProxy. For this

workflow, only the corridor solids are considered. The user must extract the solids from the corridor, assign the

necessary property sets and, via the WBLOCK command, create a separate DWG file containing only the selected

solids. The name of the new file must not change through the design cycle to enable the model updates across

Civil 3D and Revit (i.e. <DocumentName>_Solids.dwg).

Load the solids file in Civil 3D, open Revit and load the model with the shared coordinates setup. Use the

CivilConnection RevitUtils.ExportIFC node to create an IFC file in the same folder of the Revit model named as the

solid DWG file with a “_Origin” suffix (i.e. <DocumentName>_Solids_Origin.ifc). The Revit file must be saved with

the name before attempting to export the IFC.

Linear object modifiers

Civil 3D is the tool used to define the linear coordinate systems and the continuous / linear objects (e.g.

carriageway, deck, and retaining walls). Conversely Revit is used to create and manage the discrete objects (e.g.

abutments, girders, columns, foundation slabs, equipment, and piping systems). In this workflow Dynamo is used

as a prototyping environment to create the geometry components that will drive the Revit elements and to introduce

the modifiers to the Civil 3D linear objects. For example, Dynamo can be used to create the skew angles of a bridge

deck or to create the recesses and openings for the equipment along a tunnel or to add the counterforts in a

retaining wall.

These modifiers can be added to the Civil 3D model and maintained dynamically using Revit and Dynamo via

CivilConnection. It is possible to store the results of a geometry calculation in Revit using a DirectShape node from

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 34 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

the Revit shelf. This element representation can be linked to the Civil 3D model and, using the entity handle, it is

possible to assign the property from the Revit object to the Civil 3D object without losing information nor user

intervention.

If the modifiers are solids they can be added to the Civil 3D model or they can be used to cut the existing solids in

the Civil 3D model preserving the individual elements. In the second option, the layer that contains the solids will

be frozen by default. This is a design choice so that the end user is invited to verify the outcome of the automation

and validate what solids can be used to update the IFC.

Revit

IFC Import Settings

Before Linking the IFC in Revit, set up the IFC Import Settings for the IfcBuildingElementProxy class. Assigning it

to Generic Models is usually fine.

Figure 18: IFC Import Settings

IFC Shared Coordinates

Linked IFC cannot have shared coordinates in Revit, so the below workflow is used as a workaround to force Revit

to link the IFC file required for this Linear Structures workflow with the defined shared coordinates.

It is possible to link directly the intermediate Revit file that Revit automatically produces by linking the IFC in the

Revit host model. This file can acquire the shared coordinates from the host model just like any other Revit linked

model. Reopening the Revit host file will reload the latest version of the IFC link.

The intermediate Revit file is saved in the same folder as the IFC file and it is named after the input IFC file,

including the “.ifc” extension with a “.RVT” (capital letters) extension , for example:

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 35 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

<DocumentName>_Solids_Origin.ifc.RVT

The name of the IFC file must remain the same for the entire design cycle. This updates the intermediate Revit file

linked in the host Revit model. Linking a new version of the IFC file in Revit (it must be a different Revit document,

even a new, blank document will do) will override the intermediate Revit link. Reopening the host model will load

the latest Revit link.

Shared Parameters

CivilConnection generates a list of shared parameters that is assigned to all Revit categories. These parameters

are the minimum necessary to manage a Revit element in relationship to a linear coordinate system in Civil 3D.

The GUIDs of these shared parameters are hard coded in CivilConnection, so they can be safely used to create

schedules and tags across multiple projects and they will stay the same during the update cycles.

These parameters are compiled automatically by CivilConnection when the elements are controlled by Dynamo. If

the Revit elements are created manually it is necessary to assign a corridor feature line to them (i.e. a linear

coordinate system) from the Civil 3D model to enable the update capabilities of CivilConnection.

If these shared parameters are not present it is necessary to create at least an object via CivilConnection. The

shared parameters are bound to the Revit categories and they might differ depending on the nature of the objects

(single point, linear, multiple placement points or sketch based, etc.).

Table 10: CivilConnection Shared Parameters

Parameter

Description

ADSK_Corridor

The name of the corridor in the Civil 3D document that was used to extract the

feature line.

ADSK_BaselineIndex

An integer that represents the position of the baseline that contains the feature

line in the corridor structure in Civil 3D.

ADSK_RegionIndex

An integer that represents the position of the baseline region that contains the

feature line in the corridor structure in Civil 3D, read-only.

ADSK_RegionRelative

A length value that represents difference between the station along the

alignment used to describe the Revit element and the starting station of the

baseline region, read-only.

ADSK_RegionNormalized

A numeric value that normalizes the Region Relative against the difference

between baseline region ending and starting stations, read-only.

ADSK_Code

The Point code that identifies the feature line.

ADSK_Side

The side of the first point of the feature line geometry with respect to the

baseline. If the offset is less than zero the side is Left, otherwise Right.

ADSK_X

A length value that defines the World Coordinate System X coordinate of the

Revit element location, read-only.

ADSK_Y

A length value that defines the World Coordinate System Y coordinate of the

Revit element location, read-only.

ADSK_Z

A length value that defines the World Coordinate System Z coordinate of the

Revit element location, read-only.

ADSK_Station

The length measured along the alignment that defines the baseline for the Revit

element location.

ADSK_Offset

The distance between the Revit element location and a point on the feature line

at the same station measured on the local XY plane.

ADSK_Elevation

The distance between the Revit element location and a point on the feature line

at the same station measured on the local XZ plane.

ADSK_AngleZ

The rotation angle between the Revit element orientation and the feature line

horizontal direction at the same station with reference to the local Z Axis.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 36 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Parameter

Description

ADSK_Update

Yes/No parameter that will include or not the Revit element from the update

process. Default is Yes.

ADSK_Delete

Yes/No parameter that will delete the Revit element during the next update

process. Default is No.

ADSK_Multipoint

A parameter that captures the JSON representation of the parameters

necessary to describe more complex objects such as adaptive components or

floors.

ADSK_EndStation

The length measured along the alignment that defines the baseline of the end

point of the Revit element location curve.

ADSK_EndOffset

The distance between the end point of the Revit element location curve and a

point on the feature line at the same station measured on the local XY plane.

ADSK_EndElevation

The distance between the end point of the Revit element location curve and a

point on the feature line at the same station measured on the local XZ plane.

ADSK_EndRegionRelative

A length value that represents difference between the station along the

alignment used to describe the end point of the Revit element location curve

and the starting station of the baseline region, read-only.

ADSK_EndRegionNormalized

A numeric value that normalizes the End Region Relative against the difference

between baseline region ending and starting stations, read-only.

The IFC workflow also generates shared parameters that are describing the IFC properties of the elements as well

as the Property Sets attached to the Civil 3D objects. Using CivilPython it is possible to extract the values of the

property sets form Civil 3D objects and populate the same shared parameters on the Revit families that replace

the IFC link for the continuous elements in Revit.

Create Revit elements

The RevitUtils.CreateFamilyInstance node creates single point family instances along a feature line at given station

with local offset, elevation and rotation values. The objects are created in Revit and the shared parameters

compiled by CivilConnection.

Multipoint objects

Objects in Revit are not only single point or curved based, they can be sketched based (e.g. floors) or have multiple

control points (e.g. adaptive components). Revit needs, in principle, ten parameters to define a point in space with

reference to a corridor feature line, having all those parameters for any extra point describing an object would not

be practical in Revit. In CivilConnection it is possible to create Multipoint objects that are made of a

ShapePointArray which in turn is an ordered list of ShapePoints. A ShapePoint embeds the necessary parameters

and each one of them occupies a defined position in the sequence that makes up the Multipoint. These values are

serialized to a JSON string and stored in the ADSK_Multipoint parameter. In principle a Multipoint could even be

defined by ShapePoint objects referencing feature lines in different corridors (e.g. useful to create cross passages

in tunnels). A Multipoint can be used to create an adaptive component that has the same amount of control points.

Another application is for floor with a slope.

In Dynamo for Revit the only methods exposed to create floors create planar floors but when in linear structures

projects it much more frequent that floors are following a slope by design. In the Revit API it is possible to modify

the secondary elements of a floor, but the resulting element may have inaccuracies in the thickness depending on

the type properties. If in the structure of the Revit floor there are no layer set to variable, the thickness value will be

used to create a vertical offset of the top surface of the floor rather than recalculating the bottom surface.

CivilConnection implements a method in the Revit API that returns a floor by sketch with a slope arrow. The slope

is calculated as the best-fit plane for all the points contained in the Multipoint.

If the points share all the same elevation, the sloped floor will return a standard floor by sketch with no slope.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 37 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

MEP curves and fittings

In CivilConnection there are utilities to support the creation of Revit MEP curves: pipes, ducts, conduits and cable

trays. These elements follow the same principles of other objects created via CivilConnection and their relationship

with a feature line is captured in the shared parameters. The user needs to select the object types and the system

type where supported (pipes and ducts), and for each pipe segment a Dynamo curve in relationship to the feature

line used as a linear reference. The MEP curve will use the start and end points of the Dynamo curve and will

create the corresponding Revit object.

The size of the Revit object must be set after the creation, this can be achieved via Dynamo for Revit setting the

size parameter value by name and choosing the appropriate value from the sizes associated with the object type.

When two or more MEP curves (e.g. pipes) are concurrent they can be joined in Revit to for what is called a system.

The systems are used in Revit for organizing the design and support calculations. In the UI this is possible adding

elements called fittings that use the connectors on the MEP curves to provide continuity. Depending on the

geometry configuration the fittings will adapt, the available combinations are for two, three or four concurrent MEP

curves. These complex geometry calculations are managed by Revit that is accessing the connectors in the objects

involved in this process. A connector carries the information of the location, orientation and size of the face of the

MEP element it belongs to.

The two connectors configurations are:

• Elbow: when the centre lines of the MEP curves meet in one point and form an angle greater or equal to

5°.

• Transition: when the sizes of the connectors have different values.

• Union: when the centre lines of the MEP curves are parallel (not necessarily collinear).

The three connectors configurations are called Tees, the four connectors configurations are called crosses.

Tees and crosses are used when two main MEP curves intersect, and the creation of the fittings results into splitting

the main MEP curves respectively into three or four objects.

There are also connections along the length of a MEP curve (called tap) that do not split the main curve.

CivilConnection provides tools for the two connectors configuration, the connection type is determined

automatically by the geometry of the curves involved. Should the creation of the fittings fail, CivilConnection

attempts to connect the MEP curves directly between each other. This is possible via API but it is not allowed in

the Revit UI. The system that results even without fittings supports calculations and allows to have continuity

between elements with very small angles between curves which are very common in a linear structures context.

CivilConnection populates the parameters of the MEP curves with relation to the linear reference (e.g. starting and

ending station of a pipe). During the update, CivilConnection attempts to preserve the continuity of the system so

that, for example, the user can modify the offset value of one end of a pipe and the other pipes preceding and

following will also adapt their geometry to accommodate the modification without breaking the system.

Assign Featureline

Revit models can be created manually using the standard UI tools or even using Dynamo for Revit nodes. If these

objects need to later take part to the update of the model depending on the Civil 3D input changes the need to be

assigned to a feature line. The RevitUtils.AssignFeatureline node calculates the values of the shared parameters

that CivilConnection uses to update the location and orientation of Revit elements. This can be also used to assign

a different feature line to a Revit element that was created via CivilConnection nodes.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 38 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

XML Object Files

To update the location of the objects using CivilConnection it is necessary to rely on the values of the shared

parameters on the Revit elements. The RevitUtils.ExportXML node saves an XML file with the Revit model that

contains references to the objects that have the necessary shared parameters compiled to enable the update

process. This is a necessary safety measure to avoid failures during the update cycle.

CivilConnection automatically generates the XML file before attempting the update of the model with

RevitUtils.UpdatedObjects node.

Revit Links

The CivilConnection offers the possibility to place and manage Revit Link Instances as if they were family instances.

The insertion point used to place and rotate the Revit Links is the project base point of the origin. In the first release

of CivilConnection for Revit 2017 it was not possible to assign shared parameters to Revit link instances. For this

reason, the name of the instances is used to store the necessary information to manage links location updates.

It is also possible to create the Named Sites directly in the Revit Link document so that it is possible to reconcile

the location of a Revit Link Instance from the host file.

Dynamo

Dynamic Relationships

The intelligence to read information from the Civil 3D model, drive Revit components and create linear modifiers

resides in Dynamo files (DYN). Dynamo natively provides the ability to update Revit elements if there is a one-to-

one relationship between a Revit model and a Dynamo file. The results of the automation are captured in the DYN

file and they are used to update the Revit model if the input changes. The visual programming environment is ideal

to understand the relationships among objects and their hierarchy within a linear structure. It is worth noting that

the update mechanism is triggered only when the graph is used within the full Dynamo UI and it instead it is not

available via Dynamo Player. In CivilConnection the update workflow is explicit and intentional, therefore it can be

triggered even with Dynamo Player to take advantage of the simplified user experience.

The CivilConnection package extends these capabilities starting from a Civil 3D corridor input and enables the

roundtrip of information across the model authoring platforms.

Depending on the Linear Structures the dynamic relationships needed to define the linear asset can vary, the basic

principles though remain the same (linear coordinate systems, lean workflows and interoperability of information).

CivilConnection can send commands to the command line in Civil 3D and executing CivilPython it is even possible

to dynamically update Civil 3D elements.

XLSX Location File

Using the linear structures workflow, the approach to modelling MEP for a linear structure can change significantly.

The effect is to ‘host’ the equipment in the linear coordinate space controlled by Dynamo.

To simplify the scripting logic for modellers it is possible to take the parametric relationships of the equipment to

the structure to a spreadsheet and enable, for example, the definition and placement of the equipment and MEP

components starting from an Excel input. The spreadsheet can be read by the Dynamo graph and the information

used to place or update the elements in the models.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 39 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 19: Example spreadsheet containing MEP Family selection and location parameters

4.2.5 Model Updates

In this workflow, the model authoring outcomes are captured in Civil 3D and Revit while Dynamo retains the

intelligence that provides the means to update the models if the inputs change. When the design setup has been

executed properly and the references are preserved (same names for the IFC file, same names for the corridors

and the point codes used, etc.), the model content will update.

Another example of model update use is on model adjustments to resolve conflicts. The user can manually specify

the values of the shared parameters on a Revit element and let CivilConnection recalculate the position and

orientation of the object. This implies that the values input does not depend on the frequency of the stations in the

Civil 3D corridor. In fact, the values are passed to Civil 3D that recalculates the location and orientation dynamically

and update the location and the parameters of the Revit elements.

4.2.6 CivilConnection Known Issues

Geometry working range warnings

Dynamo 1.3 introduced the concept of working range geometry (in Dynamo 2.0 it is called geometry scaling). This

was intended to provide the Dynamo session with an adequate level of precision in representing numbers. Design

Script, the language that executes the Dynamo graphs at runtime, allows only for 14 digits numbers, so the resulting

precision of the decimal digits varies with the number of digits used for the integer part. Therefore, quite often,

dealing with world coordinates for linear structures projects, produces geometry working range warnings. In

general, it has been noticed that for metric projects the best representation is obtained setting the geometry working

range to Medium.

Using Large or Extra Large affects the geometry objects definition, for example the poly curves returned for the

feature lines are not continuous and the coordinate systems result scaled.

Null feature lines

When a corridor model returns null feature lines, regardless the code provided, it might indicate that the geometry

underlying the feature lines in Civil 3D failed to be generated in Dynamo. This is frequently due to a vertical profile

that does not cover the entire range of stations for a corridor region. Even if the feature lines are visible in Civil 3D

this does not mean that they are good enough to be used in the Linear Structures workflow.

This issue is clearly visible from the poly curve that represents a baseline: the range of stations where the profile

is not defined remain at elevation 0, just like the alignment.

Excessive station frequency

The station frequency defined in the corridor affects how feature lines will be tessellated. The higher the frequency

the more points there will be to process at detriment of the CivilConnection performance. It is up to the designer to

define the optimal frequency for the automatically managed corridor stations and when to add extra stations

manually to ensure the proper design intent. For a corridor that defines the structure in a metric system, a frequency

of 20m along tangents, with 5m along the curves and spirals with a mid-ordinate of 0.1m that takes into account

both curvature and increment produce, in general, a fairly precise representation with manageable feature lines in

CivilConnection. Higher frequencies are not recommended.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 40 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

The above values might change for different situations and the user should find the ideal values on a project basis.

The frequency becomes excessive when the CivilConnection performance is not acceptable (it takes too long to

elaborate) or in the worst cases, when the feature lines return null values. This is determined by the geometry

working range and some specific combination of stations for the regions in a corridor. For example, an alignment

built out of a best fit through points could be made of very short entities like line and arcs, Civil 3D will automatically

add a station at the beginning and at the end of each entity and it will add one in the middle along curves. If the

stations are too close to one another causes the extraction of feature lines to fail.

A possible resolution is to lower the frequency, rebuild the corridor and try to extract the feature lines again. If the

problem persists it might be worth to change the stations for a region: if it is possible to “stretch” a little the

extensions of a region this will force the CivilConnection to rebuild the poly curves underlying the feature lines. If

the problem persists it might depend on the alignment used to generate the corridor. In that case it might be worth

to consider using a 3D tessellated feature line or remove some of the arcs from the alignment definition. This

reduces the number of stations automatically added to the corridor and should improve the chances to extract the

feature lines from it.

As a last resort, the feature lines in CivilConnection can be created using the Corridor.GetFeaturelines node.

This method uses a temporary LandXML file to extract the coordinates of the points in a feature line. This approach

can be very slow as the LandXML might contain surfaces and other extraneous objects, furthermore being a “last

resort” method is not intended to produce an accurate representation of the feature lines of the corridor. For

example, if the subassembly used was set to “centred”, the resulting objects will have a side value of None and

only one feature line per region is returned.

Execution time

Dynamo supports three running modes: Automatic, Manual and Periodic. Remember to execute the graph in

Manual mode especially for expensive calculations, for example placing Revit objects or updating model elements.

The execution time is directly proportional to the length of the corridor and the station frequency.

Point code naming convention

The Linear Structures workflow is based on corridor feature lines.

These feature lines are defined via the point codes on the subassemblies, the point codes should be clear and

avoid confusion throughout the design cycle across the multidisciplinary team.

It is important to define a syntax for the point codes and make sure it is applied to all subassemblies. The

recommendation is to not hardcode the point code in the subassemblies but rather used input parameters that

could be overwritten from the corridor model. This method allows to be more flexible during the model authoring

process and align the point codes naming convention to suit both Civil 3D and CivilConnection. The point code

naming convention should be defined in the BIM Execution Plan.

Non-unique point codes

Civil 3D automatically attempts to build the feature lines in a corridor connecting the same point codes along the

corridor and across multiple regions. Although this is tolerated from a pure Civil 3D perspective, it has to be avoided

in the Linear Structures workflow. The reason is that the point codes applied to multiple points in the assemblies

can produce crossing feature lines and this is undesirable because it can generate confusion and unexpected

results. The feature lines are continuous linear reference systems and having them crossing each other without

control defeats their purpose in the workflow. Corridor feature lines can be used as targets across multiple models

(i.e. the edges of the carriageway from the road corridor can drive the width of the deck corridor), for this reason it

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 41 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

is important to avoid malformed feature lines, or potential confusion. Using separate baselines in conjunction with

coordinated assemblies in the same corridor can reduce this risk.

Overlapping feature lines

When subassemblies share points with the same point code assigned, overlapping feature lines are generated in

the corridor and therefore in CivilConnection. Using parameters instead of hardcoding the point codes into the

subassemblies allows the end user to decide which subassemblies in the assembly bear the point code information.

In principle, it should be possible to assign unique codes to all the necessary points and maintain continuity across

regions or apply different naming conventions in different projects reusing the same subassemblies. Ultimately

overlapping feature lines impact negatively on the performance as they are computed more than once and because

they can generate confusion. Corridor feature lines can be used as targets across multiple models (i.e. the edges

of the carriageway from the road corridor can drive the width of the deck corridor), for this reason it is important to

avoid malformed feature lines, or potential confusion. Using separate baselines in conjunction with coordinated

assemblies in the same corridor can reduce this risk.

Data values limitations

Revit has a limitation on the input via user interface for lengths (9144m or 30000 feet) and often stations values

are greater than this. The Revit user interface prevents edit and entry of these values, but it is still possible to edit

them via the API or via Dynamo.

Figure 20: Value error via Revit User Interface

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 42 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 21: Change values via Dynamo

Conflicting versions

The CivilConnection package comes in two different versions, one for Civil 3D 2017 and one for Civil 3D 2018.

If they are both installed on a machine this will cause a conflict when working from Revit 2017 like the one shown

in the picture below.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 43 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 22: Conflict loading the CivilConnection 2018 in Revit 2017

When launching Revit 2018 this exception will not be raised. In both cases though, only the CivilConnection 2017

will be loaded in Dynamo (under the Autodesk2017 shelf), so the CivilConnection 2017 will work only with Civil

3D 2017.

When attempting to use CivilConnection 2017 with Civil 3D 2018 a warning will be raised like the one shown in

the picture below.

Figure 23: The CivilConnection 2018 cannot connect to Civil 3D 2017

A similar warning will be raised when attempting to use the CivilConnection 2017 with Civil 3D 2018.

To use with Civil 3D 2018, CivilConnection 2018 must be used and the CivilConnection 2017 version must be

disabled (for example uninstalling the package).

The Dynamo graphs (DYN files) developed using both versions remain compatible.

When launching Civil 3D from a shortcut that is not properly configured can cause the same warning message.

Make sure that the shortcut target settings are forcing to start the Civil 3D product rather than the generic AutoCAD.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 44 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 24: Correct settings for the shortcut target

4.3 CivilPython

This is a command that executes Python scripts in the Civil 3D application. It is based on the same IronPython 2.7

that is present in Dynamo for Revit. The scripts can access the .NET API in Civil 3D and take advantage of the full

range automation framework. Python scripts must have a “.py” extension and can be developed with any text editor.

Changes to the code can be made on the fly, simplifying the prototyping process. In case of failures and during

debugging, a message will show the user the line in the code that requires attention.

Calling “Python” at the command line will activate the user interface of the command that will guide the user in

selecting the script to execute.

Calling a “-Python” at the command line, with a dash in front, will prompt the user for the path to the script to execute

in the command line.

With the last option it is possible to call any Python scripts directly from Dynamo via the CivilConnection node

CivilDocument.SendCommand, providing the document in Civil 3D and the file path to the Python script to execute.

Data can be processed in Dynamo and then passed as an argument for the Python script via command line in Civil

3D, for example as a JSON string that gets deserialized in the script, or again it can be dumped to a CSV file then

read in the script using the default Python libraries. It is up to the script owner to decide how to consume which

data, with which structure, and in which format.

4.3.1 Example use - Manage Property Sets via CivilPython

With CivilPython it is possible to write a script that accesses the objects in the Civil 3D model and gets or sets their

Property Set values.

In the examples below, the Python script called DumpPropertySets.py searches for the Property Sets names and

extracts their definition data to a CSV file. This can be used to build a schema in Excel to insert data on the objects.

The Python script called ReadCSVPropertySet.py reads a CSV file instead, selects the Civil 3D objects via their

handles and updates the Property Sets values.

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 45 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

In both cases the end-user that does not have Python or API skills can still benefit from these scripts as they only

have to select the scripts using a standard dialog and let CivilPython take care of the rest.

If an exception is raised, then the script owner must take action and resolve it or indicate a solution to the end-user.

For example, if the names of the property sets cannot be found, they must be added to the Civil 3D model first.

A good script should always handle the exceptions and inform the user of the possible causes and resolutions.

Figure 25: Excerpt of the script dumping Civil 3D Property Sets to a CSV file

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 46 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 26: Excerpt of the script populating Civil 3D Property Sets on objects reading from a CSV file

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 47 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

CivilConnection Snippets

This section gives a list of the common node configurations available with the CivilConnection package. The list is

far from being exhaustive and its sole purpose is to demonstrate how to combine the most frequently used nodes

to access the information from a Civil 3D model.

Figure 27: CivilApplication

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 48 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 28: GetDocuments

Figure 29: GetCorridors

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 49 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 30: GetCodes

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 50 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Figure 31: GetFeaturelinesByCode

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 51 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

CivilConnection Nodes Quick Reference

UNDER REVIEW

Autodesk

Linear Structures Workflow Guide

Global Consulting Delivery

Page 52 of 53

Version No: 2.0

The information in this document is to be considered Confidential to Autodesk, Inc., and cannot be reproduced or

redistributed without the prior written consent except internally for purposes of review and consideration of this document.

Document Control

Change history

Date

Version

Author

Description

6-May-19

1.0

Update

Approval history

Date

Version

Approver

Comments

Click here to enter a date.

Abbreviations

Term

Description

IFC

Industry Foundation Classes format file. Open format defined by BuildingSmart International to

communicate BIM data.

XML

eXtensible Markup Language code in human readable format used to define and describe the

format of data

Dynamo Graph or script

Dynamo is a graphical or visual programming language and prototyping environment within the

Revit product. The graph (or script (synonymous)) defines a procedure for creating an output of

some kind. It is saved in a .dyn file.

EIRs / AIRs

Employer Information Requirements / Asset Information Requirements

Terminology

Term

Description

CivilConnection

Custom Dynamo Package integrating Civil 3D and Revit data and workflows

BIM Use

Definition of the suitability and purpose of creation of a model in a BIM system or framework.

Shared Coordinates

Revit terminology for defining the real-world coordinate space relationship to the current model

being defined. Coordinate space needs to be shared across all models that will be linked to form

the overall project

Autodesk and the Autodesk logo are registered trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA

and/or other countries. All other brand names, product names, or trademarks belong to their respective holders. Autodesk

reserves the right to alter product and service offerings, and specifications and pricing at any time without notice, and is not

responsible for typographical or graphical errors that may appear in this document.

Blank End Page

Linear Structures Workflow Guide

Navigation menu

Versions of this User Manual:

Views

Navigation