Integrating Autodesk® Revit® Structure with
Analytical Software (SE1868)
Desirée Mackey, PE
Structural Engineer, Martin/Martin
© 2012 Autodesk
Class Summary
When it comes to analytical software, there are numerous options for which software to use
and how exactly to use that software with an Autodesk Revit Structure software model. This
class will cover when Revit models should be exported to analytical packages and how
best to prepare a Revit model for use in analysis software. We will provide a
comprehensive overview of the different analytical software options, including RISA,
Bentley® RAM Structural System®, Fastrak from CSC, ETABS from CSi, and Autodesk®
360 Structural Analysis for Autodesk® Revit®. We will compare and contrast the different
software packages and look at benefits, drawbacks, similarities, and differences among
them. To visualize the comparison, we will actually round-trip a model that was created
based on a level from Angry Birds (just to make it fun!). This class will take a balanced look
at these software packages from the perspective of the end user.
© 2012 Autodesk
Learning Objectives
At the end of this class, you will be able to:
Understand
the levels of interoperability of several analytical software packages with Revit
Structure
Understand
which elements will/will not transfer between Revit Structure and various
analytical software packages
Compare
and contrast how different analytical software packages interact with Revit
Structure
Take
a large amount of research and testing into account when considering which
analytical software packages to utilize/try out in conjunction with Revit Structure
© 2012 Autodesk
Goals of the Session
Wide
view of software
Unbiased
Focus
Not
comparison – equal time/slides/bullets
on breadth of information
focusing on details of the analysis software packages
Have
a little fun
Discussion/Questions
for the experts from each company
© 2012 Autodesk
Overview

Introduction
 Questions: When, How and Where to Start
 Discuss five software packages: do’s, don’ts and tips

RISA
 RAM
 Fastrak
 ETABS
 Robot

Comparison of the above packages
 Open discussion – time permitting
© 2012 Autodesk
Introduction
© 2012 Autodesk
Introduction – Revit Structure

Revit Structure intended to:

Convey 3D geometry
 Hold information
 Produce construction documents

Revit Structure not intended to:



Perform comprehensive structural analysis
Create/produce calculations
Carry out intricate or complex design tasks
© 2012 Autodesk
Introduction – Analytical Software

Analytical software intended to:

Analyze and/or design structural elements
 Accurately model/represent structural systems, loads, load paths
 Produce data/calculations

Analytical software not intended to:



Accurately convey all geometry, especially intricacies
Produce construction documents
Coordinate with other disciplines
© 2012 Autodesk
Introduction – Revit Structure with Analytical Software

Meant for entirely different purposes

A big task to seamlessly integrate

Frequent updates of both creates a moving target effect

Thrown together in the name of efficiency
© 2012 Autodesk
Exporting/Importing Models
© 2012 Autodesk
Questions to Consider

Will an analytical software package be utilized in the design?

Is there adequate interoperability?

Was the Revit Structure model started/complete (enough) before
needing an analytical model?

Was the Revit Structure model created with the intent to send to an
analytical software?
© 2012 Autodesk
Questions to Consider

Does the project require a comprehensive analysis?

Does the project require a specific analytical software?

Does the analytical software support model exchanges with Revit
enough to make the process viable?

If an analytical model is created prior to a Revit model, does that
software support exporting into Revit?
© 2012 Autodesk
Questions to Consider

Does only part of the structure require analysis? If so, perhaps only part of the
model should be exchanged?

Is the person creating the Revit model adept enough at Revit enough to also
create and maintain a viable analytical model?

Is it more time/cost-effective to just have two separate people maintain two
separate models?

Will the export be one-time, or will the model be “round tripped”? Given the
chosen analytical software, and its interoperability, does that affect the
decision?
© 2012 Autodesk
Which Direction?
© 2012 Autodesk
Things to Think About

Most analytical software packages recommend starting in Revit, but
not all

Always clean-up, so which software is easier to manipulate?

Is the modeler/engineer more comfortable in one or the other?

Which model is required to start first?

Many factors to consider
© 2012 Autodesk
Reasons to Start in the Analytical Program

Analysis is required prior to starting the Revit model (or receiving the
Architectural model)

The engineer is more efficient/comfortable in the analysis software

Any specific required features, benefits, or limitations in either software
that make starting in the analytical more appropriate/efficient
© 2012 Autodesk
Reasons to Start in Revit

Revit is more readily used and understood

Revit likely used on every project, not every project requires analytical
software, and not the same software at that

Revit seems to advance its analytical features often

Important to make sure the geometry is properly represented

Revit ultimately produces the construction documents
© 2012 Autodesk
Preparing a Revit Structure Model for Export
© 2012 Autodesk
General Best Practices

Pay attention to analytical lines

Make sure analytical lines intersect properly

Try to model on levels

Consider how the levels are viewed in the analytical software

Model level-to-levels, avoid unconnected heights
© 2012 Autodesk
General Best Practices

Consult the specifics of the intended software regarding how to handle
multi-span or multi-level elements

Use the “approximate curve” option for curved beams if practical

Consider only updating sizes if updating geometry is not required

Floors, slabs, and roofs generally are not well updated, so consider
only sending them one direction, one time – consider excluding
openings
© 2012 Autodesk
General Best Practices

Only export what needs to be analyzed

Create visibility filters, or use some other appropriate process to keep
track/keep organized – or use the ones provided

If needed, model “dummy” sizes (ridiculously large or ridiculously
small) to help keep track of what has been designed – if needed

The process is not perfect and there will be some amount of “clean up”
regardless of analytical software
© 2012 Autodesk
Research Introduction
© 2012 Autodesk
Software Researched

RISA Technologies

RAM Structural System

CSC Fastrak

CSi ETABS

Autodesk Structural Analysis – Robot Structural Analysis
© 2012 Autodesk
Research Methods

Documentation review

Consultations with experts on each of the analytical software packages

A few quick tests

One basic model test
© 2012 Autodesk
Research Results
© 2012 Autodesk
RISA Technologies

RISA 3D – Three dimensional structural analysis for steel, concrete,
masonry, cold-formed steel, aluminum and timber

RISA Floor – Comprehensive analysis for floor systems

Link available as a free download

Active Autodesk partner and determined to advance with Revit
© 2012 Autodesk
RISA – Notable elements that work

Curved beams
 Beam Systems (members only)
 Continuous/cantilevered beams
 Braces (vertical only)
 Trusses (members only)
 Steel Joists
 Floor slabs, two-way slabs
 Slab edges
 Walls
 Openings: by face or wall, Arch door and window
 Isolated footings
 Loads, Load cases, Load combinations
© 2012 Autodesk
RISA – Notable elements that don’t work

Openings: shaft and profile/boundary

Foundation slabs

Horizontal braces

Rebar/hosted rebar

Wall footings
© 2012 Autodesk
RISA – Best Practices

Only use start/end offsets to slope beams

Use the z-direction offset to change beam elevations

Outdated shapes/old structural shapes need to be mapped to current
shapes in the mapping file

Slab edge locations are precarious – may change in Revit 2013

Openings require opening framing to transfer properly
© 2012 Autodesk
RISA – Best Practices

RISAFloor requires multi-story columns to be modeled floor-to-floor, and
continuous/cantilevered beams need to have each segment modeled separately

Check the merge tolerance settings and joint coordinates

Be careful about changing node coordinates in RISA

Reactions come back into Revit as separate parameters, RISA provides tag
families

Don’t bother with the Revit analytical checks, use the ones in RISA
© 2012 Autodesk
RAM Structural System

Complete analysis and design of steel and concrete

3D model, level based, and individual modules for different
elements/materials

Bentley software, but Bentley actually creates many add-ons for
Autodesk software

Link available as a free download
© 2012 Autodesk
RAM – Notable elements that work

Steel Joists
 Braces
 Trusses (members only)
 Beam systems (members only)
 Walls (bearing and structural combined only)
 Openings: by face or wall openings only
 Isolated footings
 Continuous/cantilevered beams (requires special setting)

Many elements work but can be exchanged once only, cannot be updated, also
will likely only transfer one way (either Revit to RAM or RAM to Revit)
© 2012 Autodesk
RAM – Notable elements that don’t work

Loads, Load Cases, Load Combinations

Openings: shaft and profile/boundary

Foundation slabs

Walls set to shear

Rebar/hosted rebar

Curved beams
© 2012 Autodesk
RAM – Best Practices

Set the reference level for braces to the top level to which they frame

Frame braces into beams and columns that are set to lateral

Default mapping of shapes are set to out-of-the box families

Loads just generally don’t work well

“Member supports” in the structural settings >>Analytical Model
Settings tab must be checked on to detect cantilevered members
© 2012 Autodesk
RAM – Best Practices

Multi-story columns in Revit are broken up at the levels in RAM

Isolated footings have to be perfectly centred on columns for the
information/sizing information to exchange properly

Continuous beams need to be modelled as separate segments between
supports to be imported properly into RAM

If exporting from RAM to Revit, export to a Revit template, not to a blank project

For slopped roofs, model flat, or at least all on one level before sending to RAM
© 2012 Autodesk
CSC Fastrak

Complete analysis and design of steel

Originally a British software, now expanded into US codes

“Seamless” communication with Revit Structure

Link available as a free download
© 2012 Autodesk
Fastrak – Notable elements that work

Beam systems (members only)
 Curved beams (only if curve is approximated)
 Braces (vertical only)
 Steel Joists
 Trusses (Revit to Fastrak only, members only)
 Floor slabs (mapping setting required)
 Stiffeners/plates
© 2012 Autodesk
Fastrak – Notable elements that don’t work

Loads, Load Cases and Load Combinations

Openings: shaft and profile/boundary

Section/size properties – attribute sets

Walls

Rebar/hosted rebar

Wall Footings
© 2012 Autodesk
Fastrak – Best Practices

Levels are required at the top of steel level

Attributes have to be assigned to all the elements once imported into Fastrak

Revit model has to be saved immediately after exporting to Fastrak


In Fastrak, slabs must be supported on all sides by a member
If exporting from Fastrak to Revit, the structural usage will have to be adjusted
once in Revit such that girders/beams/joists will have the correct line weights
© 2012 Autodesk
Fastrak – Best Practices

View filters and the “track changes” command to track changes

If analytical lines are adjusted away from auto-detect, the same adjustment
must be used at both ends of the member

Foundations are created under EVERY column when transferring into Fastrak

Revit and Fastrak models can be updated simultaneously, but any changes in
one will override the other when exported

Reactions exported only for a fully completed design model, and only if
members are designated as “gravity only” design. A shared parameter must be
added to use a Revit tag
© 2012 Autodesk
CSi ETABS

Structural and earthquake design specialty

Many modules

Information is hard to find, and what is there is outdated. Company
doesn’t seem to promote their interoperability with Revit

Link available on a paid subscription
© 2012 Autodesk
ETABS – Notable elements that work

Curved beams (only if curve is approximated)
 Steel Joists (come through as beams)
 Walls
 Floor Slabs
 Isolated Footings
 Braces (vertical only)
 Openings: wall, shaft and by face
 Loads, load cases and load combinations (some limitations)
© 2012 Autodesk
ETABS – Notable elements that don’t work

Openings: shaft and profile/boundary

Diaphragm designations

Trusses

Rebar/hosted rebar

Wall Footings
© 2012 Autodesk
ETABS – Best Practices

Diaphragms will have to be defined once in ETABS

Import/export dialog boxes appear during the import/export process

If a parametric family has an unrecognized type, ETABS will create a
corresponding shape

Windows vista bugs

End release updates are occasionally “buggy”

Material updates not transferred from ETABS to Revit
© 2012 Autodesk
ETABS – Best Practices

Z-justification and start and end offset parameters don’t always translate
properly

Only openings completely inside a wall or floor will be transferred

In-place families are imported into ETABS as frame members

Elements can be deleted upon importing/exporting, but only if the entire model
is exchanged

Load combinations can be exchanged once, but cannot be later updated. They
can, however, be deleted and replaced
© 2012 Autodesk
Autodesk 360 – Robot Structural Analysis

Autodesk 360 structural analysis in the cloud, or local analysis using
Robot

Formerly Project Storm

Large analytical updates with each of the last couple of releases

Link native in Revit
© 2012 Autodesk
Robot – Notable elements that work

Curved beams
 Beam Systems (members only)
 Braces (vertical only)
 Trusses (members only)
 Steel Joists
 Floor slabs
 Slab edges
 Walls
 Isolated footings
 Wall footings
 Loads, Load cases, Load combinations
 Rebar/hosted rebar
© 2012 Autodesk
Robot – Notable elements that don’t work

Foundation Slabs

Horizontal Braces

Families/family types that don’t already exist in the Revit project

Wall Footings
© 2012 Autodesk
Robot – Best Practices

Static analysis only if using 360

Differentiate the start and ends of members

The same person will likely model both the Revit and Analytical model,
so staff appropriately

Multi-span members will be split into separate members once in Robot

Use hosted area loads
© 2012 Autodesk
Robot – Best Practices

Send and update Revit/Robot models from Analyze tab within Revit

Upon updating the Revit model, there is an option to keep updated elements
selected

Robot will analyze and exchange some connections: end plate and column
flange connections

Sloped planes/framing are supported

Duplicate nodes will be created if analytical lines are not modeled properly
© 2012 Autodesk
Theoretical Case Study
© 2012 Autodesk
What to Model?
© 2012 Autodesk
The Physical Revit Model
© 2012 Autodesk
The Analytical Revit Model
© 2012 Autodesk
Revit Model Details

Revit Structure 2012, updated to Revit Structure 2013
 Steel and concrete members
 Walls, beams, columns, foundations, braces
 Precise analytical model
 Loads, load cases and load combinations applied in Revit – a variety
 Pigs modeled as point dead loads
 Birds modeled as point and line live loads
 Followed as many “best practices” for as many of the software
packages as possible
© 2012 Autodesk
Revit Model Details

Differentiated ends of the
analytical lines to help

In Revit 2012 roof only aligned
vertically with the members but not
always in plan. Fixed in 2013!

Floors easier to align properly

Precise intersections
© 2012 Autodesk
Revit Model Details

Intersections with many members were
harder, especially with braces

Used snapping shortcuts

Definitely more time consuming to
make both the geometry and the
analytical correct

Occasionally deleted and redrew a
member instead of trying to fix it
© 2012 Autodesk
Revit Model Details

Made pigs dead loads

Made birds different live loads

Made custom load combination
loosely based on IBC load
combinations
© 2012 Autodesk
Revit Model Details

Changed object styles to be able to
see loads and foundations easier

Changed colors to match pig and bird
colors
© 2012 Autodesk
The Revit Structure Model
© 2012 Autodesk
Exporting the Revit Model to Analytical

All links under External
Tools or their own button in
the Add-Ins Tab
 Robot under Analyze Tab
 Load ETABS last
© 2012 Autodesk
Theoretical Case Study Observations
© 2012 Autodesk
RISA

Simple, easy export dialog box

Most basic options available

Import/Export Report new in 2013

No intricate details/settings available upon
export

Exchange file should be saved in the same
location as the base Revit and analytical
files

Browse to mapping file separately but
seems less likely to need it
© 2012 Autodesk
Revit to RISA 3D

Elements, nodes, connections, end
releases come through well

All loads, load cases, load
combinations came through except for
line loads

Walls not perfect – rounding errors
with nodes create a non-planer error

Analysis ran immediately upon import
© 2012 Autodesk
RISA 3D back to Revit

Export BIM Exchange file

Import from RISA

Import/Export Report and RISA
Summary View new in 2013
(Green=new; Yellow=modified;
Black=unchanged – element
overrides)

Summary view new in 2013
© 2012 Autodesk
RISA 3D back to Revit

Everything came back in the way
it left

Family type mapping errors – not
loaded

Walls not perfect – changes in
RISA to fix the non-planer error
caused some small movement
and an “element slightly off axis”
warning
© 2012 Autodesk
Revit to RISA Floor

Elements, nodes, connections,
end releases come through well

All loads, load cases, load
combinations came through
except for line loads

Sloped roof was modeled with
different levels, so each level
came through separately and roof
was flattened – message didn’t
appear in 2013
© 2012 Autodesk
RAM

Simple, easy export dialog box

Few options available upon export

Exchange file should be saved in
the same location as the base
Revit and analytical files

Error log reports what didn’t
transfer – loads caused a problem
here
© 2012 Autodesk
Revit to RAM

Elements, nodes, connections, end
releases come through well

Loads didn’t really seem to come
through at all

Same level issue as RISA Floor –
sloped roof was split into levels

If mapping file not set to custom
families, or if out-of-the-box families
not used in the Revit model export will
fail entirely
© 2012 Autodesk
RAM back to Revit

Must have RAM model closed to send
back

Most elements returned to Revit
without issues

Loads that were originally in Revit
were not overridden

Material properties seemed to change
a bit in that the graphic displays in
Revit were no longer the same
© 2012 Autodesk
Fastrak

User-friendly import/export dialog
boxes

Many intricate options available

Reports mapping and other issues
upon export and allows the user to fix
the problems

Exchange file should be saved in the
same location as the base Revit and
analytical files
© 2012 Autodesk
Revit to Fastrak

Prompts for information about fist time
export or updating the mode

Prompts for a selection of what
elements to export

Reports mapping error/unrecognized
shapes and prompts for a solution

Individual mapping files for each type
of element/material/family
© 2012 Autodesk
Fastrak Mapping Files
© 2012 Autodesk
Fastrak

Prompts to save exported file

Warning log explains what
elements were not transferred

Save Revit file immediately after
export to maintain link with Fastrak

Two-Step process – Fastrak has
to be opening and then Revit file
imported
© 2012 Autodesk
Revit to Fastrak

Elements, nodes, connections,
end releases come through well

Only steel members come
through, but Fastrak doesn’t
analyze concrete

Attribute sets will now have to be
assigned in Fastrak
© 2012 Autodesk
Fastrak back to Revit

Again, two-step process of
exporting an exchange file and
then importing

Opportunity to “ignore position” of
elements

Good return of objects, many
material properties were changed
© 2012 Autodesk
Fastrak back to Revit

Tracking changes:
 Fastrak
adds a property to updated
elements
 Use filters to show updated elements
 Can save filters/views in project
templates to avoid creating them
every time
 Set up a Fastrak View to show
changes
© 2012 Autodesk
ETABS

Simple string of dialog boxes

Opportunity to select which
element to export

Error dialog prompting mapping
clarifications

Two-step process
© 2012 Autodesk
Revit to ETABS

Elements, nodes, connections,
end releases come through well

All loads, load cases, load
combinations came through
except for line loads

Surprisingly clean export, model
could complete an analysis
immediately upon import
© 2012 Autodesk
ETABS back to Revit

Upon Importing back to Revit,
dialog prompts for options of what
to import/update

Everything came back in the way
it left, except the line loads
appeared to change slightly

Again, surprisingly clean with few
warnings/errors
© 2012 Autodesk
Robot

Native button in Revit – Analyze
tab

Simple dialog, no intricate options
or prompts

Some options in “send options”

Launches Robot, but not demo
version
© 2012 Autodesk
Revit to Robot

Elements, nodes, connections,
end releases come through well

Loads, load cases, load
combinations came through

Analysis ran immediately
© 2012 Autodesk
Robot back to Revit

Upon Importing back to Revit, dialog
prompts for options of what to
import/update

Everything came back in the way it left

Options to select the updated
elements

Except for the separate window for
Robot, almost seems native to Revit

Makes new families if types don’t
already exist in the project
© 2012 Autodesk
Summary of Observations
© 2012 Autodesk
Summary

Everything did generally better than expected

Software generally exchanged the elements they design

RISA, ETABS and Robot exchanged the most elements and properties
with the fewest errors

Fastrak was the most comprehensive and they claim to be the best
exchange, but very deliberate…so is all this just automatic in the other
software packages so an illusion that Fastrak is better?
© 2012 Autodesk
Summary

Only one roundtrip, would the results be different if I did more?

Too much “clean-up” required for Fastrak, but if it is better with round tripping
then it may be worth it

Applying loads in Revit wasn’t always easy, and not as easy as in the analytical
packages

Look out for Autodesk and Robot to advance analytically in the coming years

Choose software based on engineering needs
© 2012 Autodesk
Questions?
Please fill out your surveys!
Contact Info:
Desirée (Dezi) Mackey
Email: dmackey@martinmartin.com
Blog: http://bdmackeyconsulting.com/blog/
Twitter: @RevitGeeksWife
LinkedIn: http://www.linkedin.com/pub/desiree-mackey/7/308/448
Autodesk, AutoCAD* [*if/when mentioned in the pertinent material, followed by an alphabetical list of all other trademarks mentioned in the material] are registered trademarks or 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
services 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. © 2012 Autodesk, Inc. All rights reserved.
© 2012 Autodesk