Integrating Autodesk® Revit® Structure with Analytical
Software
Desirée Mackey, PE – Martin/Martin
SE1868
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.
Learning Objectives
At the end of this class, you will be able to:
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Understand the levels of interoperability of several analytical software packages with Revit Structure
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Understand which elements will/will not transfer between Revit Structure and various analytical
software packages
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Compare and contrast how different analytical software packages interact with Revit Structure
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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
About the Speaker
Desirée (Dezi) received her bachelor's degree from University of California, Davis and her master's
degree from Massachusetts Institute of Technology and now is a practicing structural engineer at
Martin/Martin in Denver, Colorado. In the past several years she has been a regular Autodesk University
speaker and has spoken at Revit Technology Conference North America. In addition she is the Chair of
the Structural Engineers Association of Colorado's BIM committee, a Rocky Mountain Building
Information Society committee member, and she is currently serving as an AUGI board member as well
as Treasurer. Finally, she also acts as a partner in her husband's BIM consulting company, BD Mackey
Consulting.
Email: dmackey@martinmartin.com
Blog: http://bdmackeyconsulting.com/blog/
Twitter: @RevitGeeksWife
LinkedIn: http://www.linkedin.com/pub/desiree-mackey/7/308/448
Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
Introduction
This session is intended to be a broad overview of the interoperability of Revit Structure and
several different analytical software. The session will include some tips and tricks for using
each software in conjunction with Revit Structure, will go over the supported elements that
transfer to and from Revit Structure, and will discuss limitations associated with each software.
To some extent this session will compare and contrast the different analytical software, but be
aware that in many cases they are intended for different types of analysis, so some
comparisons may be deceiving. To help illustrate the aforementioned items, a simple structure
was exchanged between Revit Structure and each analytical software. This session will present
the findings from those exchanges.
Overview
Although Autodesk seems to eventually have different plans, for now Revit Structure is primarily
a 3D tool intended to accurately convey geometry with the ultimate goal being 2D construction
documents. Analytical software, on the other hand, is meant for code-based structural analysis
and the 3D model is only intended to clarify structural relationships between elements. The
“documents” from analytical software are printed calculations, and in some cases, seemingly
poorly organized data. These programs are meant to accurately represent load paths, and are
not expected to accurately convey geometry. Similarly, Revit is not expected to accurately
convey or analyze structural information. Therefore it follows that getting the two models, meant
for two very different purposes, to communicate seamlessly is quite an undertaking. Now, that
doesn’t mean it shouldn’t happen, it is just good to keep in mind what is truly being asked of
these products.
When it is appropriate to export to an analytical software package
The question of when depends on a large number of variables. Perhaps the easier question to
answer would be when not to export to analytical software. Here are some guidelines to
consider:
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Does the project require a comprehensive 3D analysis that requires specific analytical
software?
Is the person creating the Revit model adept at Revit enough to also pay attention
to/create a viable analytical model?
Will the Revit model be far enough along before analysis is required to begin?
If an analytical model is created prior to a Revit model, does that software support
exporting into Revit?
Does only part of the structure require analysis? If so, perhaps only part of the model
should be exchanged?
Is it more time/cost-effective to just have two separate people maintain two separate
models?
Does the analytical software support model exchanges with Revit enough to make the
process viable?
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
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Will the export be one-time, or will the model be “round tripped”?
How to prepare a Revit Structure model for analysis
There are specific best practices for each software package, but the following are good things to
keep in mind when creating a Revit model that is intended to be exported to analytical software.
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Pay attention to analytical lines
Make sure analytical lines intersect properly
Try to model on levels, not arbitrary distances away, i.e. perhaps create a T.O. Steel
level, or many levels for varying framing levels. However, keep in mind that sloped
levels, such as roofs, may require specific attention and considerations
Model between levels, avoid unconnected heights
Consult the specifics of the intended software regarding how to handle mulit-span or
multi-level elements
Use the “approximate curve” option for curved beams
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
Only export what needs to be analyzed, mark everything else as “not for analysis”,
create visibility filters, or use some other appropriate process
Model “dummy” sizes (ridiculously large or ridiculously small) to help keep track of what
has been designed and what hasn’t
Understand that the process is not perfect and some amount of “clean up” will be
required regardless of what analytical software is used
Revit to analytical or analytical to Revit?
Most, but not all, analytical software companies suggest starting the model in Revit. There are
certainly viable reasons to begin a model in analysis software:

Analysis was required prior to starting the Revit model (receiving the Architectural
model)
 The engineer is far more efficient/comfortable in the analysis software
 Any specific feature, benefit, or limitation to the interface of the analytical software and
Revit Structure such that it is more efficient to begin the model in the analysis software.
While there are exceptions, my opinion is that the models should generally begin in Revit
Structure. As time goes on engineers are becoming more and more comfortable with Revit and
Revit’s analytical features advance every year, making this workflow more reasonable. Also,
Revit is consistently the 3D modeling software utilized, and preferred analytical software may
change often. But furthermore, as engineers, our deliverable is (usually) a set of 2D
documents. Revit is the software used to create the geometry that ultimately is used to create
the 2D drawings. Therefore, I believe it is important that the geometry is correct. Although
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
there are other reasons that support starting in Revit, I believe this reason alone is enough to
suggest beginning in Revit.
Analytical Software Overview
In the next sections, five of the more widely used analysis programs will be discussed. These
sections will cover more specific best practices of each. As of when the research for this paper
was completed, the following elements were supported for exchanging between each software
and Revit Structure. Please note that as of May 2012, the Revit Structure 2013 link for the four
external programs was not yet available, so this is based upon the 2012 link.
RISA Technologies
RISA provides a number of modules including RISA-3D, RISAFloor, RISAFoundation,
RISAFooting, and more. This session will focus on RISA-3D and RISAFloor. RISA-3D is a
general 3D analysis and design software that will analyze steel, concrete, masonry, cold-formed
steel, aluminum and timber. RISA-3D will analyze both gravity and lateral loads. RISAFloor is
intended for more complete design and analysis of floor systems. The two modules
communicated seamlessly with one another.
RISA: Elements/Properties supported for exchange
 Grids
 Levels
 Beams
 Curved beams
 Beam Systems (members only)
 Columns
 Braces (vertical only)
 Trusses (members only)
 Steel Joists (RISAFloor only)
 Floor slabs
 Two-way slabs
 Slab edges
 Walls
 Openings: by face or wall openings
 Architectural window and door
openings
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Isolated footings
Pier/Pile caps
Loads (most), Load cases, Load
combinations
Reactions
Material Properties
Camber
Studs
Section/size properties
Section rotation
Structural usage (Revit to RISA only)
Continuous/cantilevered beams
(RISA-3D only)
End fixity/releases
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
RISA: Elements/Properties unsupported for exchange
 Openings: shaft and
 Rebar/hosted rebar
profile/boundary
 Wall footings
 Foundation slabs
 Phasing
 Horizontal braces
RISA: Best Practices
 Only use start/end offsets to slope beams. Do not use them to change the elevation of
the beam (use the z-direction offset for that)
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Outdated Revit shapes/old structural shapes will need to be mapped to current shapes
in the mapping file, which is very easy to use
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Once transferred to RISA Floor, slabs will look for wall or slab edges to define the edge
of the slab so the slab in Revit has to run completely over perimeter walls below, which
may not be the correct way to model the floor. Fix it once it is in RISA Floor or send it
out and then fix it in Revit, round-tripping of slabs is not recommended
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Openings require opening framing to transfer properly, so frame out the openings in
Revit prior to sending the floor to RISA
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RISAFloor requires multi-story columns to be modeled floor-to-floor, and
continuous/cantilevered beams need to have each segment modeled separately. Simply
edit the end releases in Revit or RISA for cantilevered beams
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Check the merge tolerance settings and joint coordinates. Be careful about changing
coordinates in RISA
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Reactions come back into Revit as separate parameters, RISA provides tag families
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Don’t bother with the Revit analytical checks, use the ones in RISA
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Coming soon: Supplementary “track changes” ability to track what has changed when
sending models between RISA and Revit
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Utilize the new RISA Import Summary view
RAM Structural Systems
RAM Structural System is Bentley’s analytical software for buildings. In addition to RAM
Structural System, there are several other modules including RAM Steel, RAM Frame, RAM
Concrete, RAM Foundation, and more. RAM structural System claims to be the only
engineering software created for the complete analysis and design of steel and concrete
buildings. RAM handles both gravity and lateral loads for all members in a steel or concrete
building.
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
RAM: Elements/Properties supported for exchange
 Grids* (only Revit to RAM)
 Levels
 Beams
 Columns
 Braces
 Steel Joists
 Trusses (members only)
 Beam systems (Trusses only)
 Floor slabs*
 Slab edges*
 Walls (bearing and structural
combined only)
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Openings: by face or wall openings
only
Isolated footings
Reactions
Material Properties*
Camber
Studs
Section/size properties*
Section rotation
Structural usage/Analyze as*
Continuous/cantilevered beams
(requires special setting)
End fixity/releases*
*Can be exchanged once only, cannot be updated, also will likely only transfer one way
(either Revit to RAM or RAM to Revit)
RAM: Elements/Properties unsupported for exchange
 Walls set to shear
 Openings: shaft and
profile/boundary
 Foundation slabs
 Pier/Pile caps
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Loads, Load cases, Load
combinations
Rebar/hosted rebar
Curved beams
Wall footings
Phasing
RAM: Best Practices
 Set the reference level for braces to the top level to which they frame. Braces must
frame into beams and columns that are set to lateral in “analyze as”
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Default mapping of shapes are set to out-of-the box families. Mapping files have to be
manually set and accurate for the families in the project before the file will even export.
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Loads transfer but not all load types (i.e. wind and seismic are not transferred) and some
load types are changes/name changes, i.e. snow becomes live roof and roof live
becomes live roof, load combinations are not transferred. All dead loads exported from
Revit are added together because RAM can only handle one dead load
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“Member supports” in the structural settings >>Analytical Model Settings tab must be
checked on to detect cantilevered members
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
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Multi-story columns in Revit are broken up at the levels in RAM, if the sizes of the
segments are changed in RAM, the size of the bottommost size is used when importing
back to Revit
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Isolated footings have to be perfectly centred on columns for the information/sizing
information to exchange properly
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Grid bubbles may not appear on the gridlines once imported, and Grid lines may only
show up on the lowest level
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Continuous beams need to be modelled as separate segments between supports to be
imported properly into RAM
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If exporting from RAM to Revit, do not export to an empty Revit project, export to a Revit
template. The link does not work well if exported into an empty Revit Project
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For slopped roofs, model flat, or at least all on one level before sending to RAM. If
modelled on separate levels, RAM will create separate levels.
CSC Fastrak
CSC Global focuses on providing technical software to structural engineers. Originally a British
software, Fastrak recently expanded to US building codes. Fastrak is a comprehensive building
design and analysis software for steel buildings, and for the past several years has been
regarded as the analytical software that most seamlessly communicates with Revit Structure.
Fastrak also has other modules including Fastrak Portal Fame and Fastrak Connection design.
Fastrak: Elements/Properties supported for exchange
 Grids
 Levels
 Beams
 Beam systems (members only)
 Curved beams (only if curve is
approximated)
 Columns
 Braces (vertical only)
 Steel Joists
 Trusses (Revit to Fastrak only,
members only)
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Floor slabs (mapping setting
required)
Isolated footings
Pier/Pile caps
Stiffeners/plates
Reactions
Material Properties
Camber
Studs
Section rotation
End fixity/releases
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
Fastrak: Elements/Properties unsupported for exchange
 Walls
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 Wall footings
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 Roofs
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 Loads, Load cases, Load
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combinations
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 Openings
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 Horizontal braces
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Section/size properties
Rebar/hosted rebar
Beam systems
Wall footings
Model groups
Phasing
Structural usage
Fastrak: Best Practices
 Levels are required at the top of steel level
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Fastrak uses attributes to define how an element will be designed (composite v.
noncomposite, deflection criteria, depth limits, etc.). When you model a building in
Fastrak you choose which attribute every element receives while you model. On the
other hand, if you bring in your Revit model to Fastrak, all the beams and columns will
be assigned a generic attribute. The user then needs to assign attributes to all the
elements within Fastrak. Attributes and connectivity can take a lot of time to fix,
especially if the user is new to Fastrak.
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Communication via UUID’s (Universal Unique Identifiers). The UUID’s are created in
Fastrak whenever an element is inserted into the model, however they are only created
within Revit when importing/exporting to Fastrak, so the Revit model has to be saved
immediately after exporting to maintain the UUID’s
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Transferring slabs between Fastrak and Revit. In Fastrak, slabs must be supported on
all sides by a member. This puts a separate slab in between every beam. For best
results, slabs should be modelled in both Fastrak and Revit simultaneously
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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
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It is possible to track design changes in Revit via view filters and the “track changes”
command. Have to manually set up filters and views in Revit
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If analytical lines are adjusted away from auto-detect, the same adjustment must be
used at both ends of the member
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Foundations are created under EVERY column when transferring into Fastrak so
foundations will need to be deleted after export
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
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Revit and Fastrak models can be updated simultaneously, but any changes in one will
override the other when exported, i.e. if exporting from Fastrak to Revit, the changes in
Fastrak will override any changes in Revit and vice versa
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Reactions exported for beams and braces, 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
CSi ETABS
Computers & Structures, Inc. specializes in software programs for structural and earthquake
engineering. ETABS was specifically developed for multi-story structures. CSi has several
other design software packages such as SAP2000, PERFORM-3D, SAFE, and more. One item
of note is that the “CSixRevit” link is not free, as is the case with the other software packages,
and the latest best practice documentation is intended for Revit versions 2009/2010/2011.
ETABS: Elements/Properties supported for exchange
 Grids (once only)
 Levels
 Beams
 Curved beams (only if curve is
approximated)
 Steel Joists (come through as
beams)
 Columns
 Walls
 Floor Slabs
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ETABS: Elements/Properties unsupported for exchange
 Openings: profile/boundary
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 Diaphragms
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 Horizontal Braces
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 Trusses (come through as
unrecognized frame sections)
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Isolated Footings
Braces (vertical only)
Openings: wall, shaft and by face
Loads, load cases and load
combinations (some limitations)
Reactions
Material Properties (limited, once
only)
Section/size properties
End fixity/release
Beam Systems (come through as
unrecognized frame sections)
Wall Footings
Phasing
Rebar/hosted Rebar
ETABS: Best Practices
 Diaphragms will have to be defined once in ETABS
 Import/export dialog boxes appear providing mapping editing opportunities during the
import/export process. If a parametric family has an unrecognized type, ETABS will
create a corresponding shape
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
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Windows vista: users must run as administrator (ETABS, ETABSIO and Revit.exe). If
Revit is not run as administrator then there is a possibility that CSIxRevit will not be able
to open .log file. In this case CSIxRevit will not be able to write any warning in the log
file and all warning messages will be displayed on the screen time to time. Directly
sending data to ETABS may not work if Revit is not run as admin.
End release updates are occasionally buggy
Z-justification and start and end offset parameters don’t always translate properly
Material updates of walls, decks and slabs are not transferred from ETABS to Revit.
Workaround is to create new elements in ETABS and the old will be deleted and
replaced with the new in Revit.
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
Autodesk 360 Structural Analysis – Robot Structural Analysis
Autodesk 360 Structural Analysis is a cloud-based structural analysis option; but analysis
doesn’t have to be conducted in the cloud. The analysis is conducted via Robot Structural
Analysis (Professional only if owned). Robot Structural Analysis is part of the ultimate design
suite, or can be purchased individually.
Robot: Elements/Properties supported for exchange
 Grids
 Levels
 Beams
 Curved beams
 Beam Systems (members only)
 Columns
 Braces (vertical only)
 Trusses (members only)
 Steel Joists
 Floor slabs
 Slab edges
 Walls
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Isolated footings
Wall footings
Pier/Pile caps
Loads, Load cases, Load
combinations
Reactions
Material Properties
Section/size properties
Section rotation
End fixity/releases
Rebar/hosted rebar
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Integrating Autodesk® Revit® Structure with Analytical Software
Desirée Mackey, PE
Robot: Elements/Properties unsupported for exchange
 Openings
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 Foundation slabs (turn into floors)
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 Horizontal braces
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 Phasing
Drilled pier foundations
Structural Usage
Analyze as
Robot: Best Practices
 Static analysis only. Analysis is limited by the capabilities of Robot Structural Analysis
and some analyses may require the enhanced capabilities of Robot Structural Analysis
Professional
 Consider differentiating between the start and end of analytical lines – perhaps make
them different colors using visibility/Graphic overrides
 The same person will 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 whenever possible
 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, so only one level and then element offsets are all
that are required
 Duplicate nodes will be created if analytical lines are not modeled properly (such that
their ends intersect, etc.)
Conclusion
This session provided a large amount of information on several analytical programs with hopes
of clarifying the benefits and limitations when integrating the use of these products with Revit
Structure Models. Although the analytical software themselves are different, and intended for
different types of analysis, this session also compared and contrasted each of them in relation
to their ability to interface with Revit. This session hopes to have not only offer the information
to help make the decision of which analytical software is most appropriate, but also to provide
enough information to know what to expect when beginning to use the software in conjunction
with Revit Structure.
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