Session 11
Grasshopper BIM Jon Mirtschin, Geometry Gym Pty Ltd
Class Description
Introduction to Grasshopper as a graphical programming environment and how
it can be used to author BIM data for software such as Revit. Case studies will be
demonstrated on Grasshopper plugins including Chameleon, Geometry Gym ,
Grevit, Hummingbird and Lyrebird.
About the Speaker:
Jon Mirtschin, received his Bachelor of Engineering/Science from the University of
Melbourne in 2001. He worked as a structural engineer for Connell Wagner and
Expedition Engineering before starting Geometry Gym Pty Ltd, specializing in
Computational Geometry and BIM software tools, particularly for model
exchange between different software platforms.
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Grasshopper BIM
Note that the comparisons/observations/links are current at the time of
preparation, April 2015. Features and capability can change dramatically if a
new version is subsequently released so please review if you are using this guide
to check for accuracy.
Grasshopper has emerged as a very popular graphical programming
environment for architects and engineers. With a powerful geometry kernel and
an ability to generate and assess a multitude of options, it is a powerful tool
particularly in the conceptual and early design phases of a project
development.
However Rhino/Grasshopper are not so strong in required functionality for later
stages of design in terms of scheduling and technical drawing production. So it
is natural that many designers are looking to exchange their model data from
Grasshopper to software such as Revit for performing these tasks.
The demand for Grasshopper to Revit has motivated several users to develop
plugins to enable and automate this process. This paper should assist users in
determining which of these offerings might best suit their needs.
Factors to consider include:
Purchase Cost – Nearly all are free, some require payment.
OpenSource – Some are openSource, permitting the opportunity for
external customization or participation in improvements
Improvement activity and bug fix response – One project appears to be
abounded, a few are done as hobbies or based on in-house requirements
and it is unlikely and unreasonable to expect support and rapid response
in this case. Others are developed and sold with support. “You get what
you pay for” is an old saying, but not to say that the free versions aren’t an
economic choice if functionality is as needed.
Versions – Some plugins will only support or update the latest versions of
Grasshopper/Revit, others will support (with active improvements) to older
versions
Operation time – Some plugins are a (near) one click exchange, others
require user management and intervention. For firms the “time cost” of
staff can quickly make the commercial alternatives a money saving
investment.
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Operation – Some plugins send the data from Grasshopper to Revit using
API pipelines or TCP/IP traffic, others use interim file saving measure. On
large models locking up a computer, rhino license and revit license for the
duration could be problematic. Also the process is reported to be
temperamental with some of the tools causing crashes. Some plugins use
text files or file saving which also has a benefit of a record of the
exchange conducted.
Updating Revisions – Plugins have varying ability to update/replace/delete
previous model objects when subsequent exchanges are conducted.
Some will require manual intervention.
I’ve tried to compile this handout with an “unbiased” point of view, but you
should certainly seek the opinions of others (also considering any bias they might
have). Here’s some links.
http://collectivebim.com/gh-to-revit-plugin/
http://www.grasshopper3d.com/group/gh-revit
http://bim42.com/tag/plugin/
http://revitstickynotes.blogspot.com.au/2012/06/grasshopperrhino-and-revit.html
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Lyrebird – lmn architects
http://lmnarchitects.com/tech-studio/bim/superb-lyrebird/
Status – Active
Latest Update - November 2014
Download - http://www.food4rhino.com/project/lyrebird?ufh
Revit Versions Supported – 2016, 2015 and 2014
Development - Open Source https://github.com/logant/Lyrebird
Operation – Sends data directly from Grasshopper to corresponding Revit plugin.
Hummingbird – Tim Meador and Mario Guttman
https://ghhummingbird.wordpress.com/
Status – Active
Latest Update - April 2015
Download - http://www.food4rhino.com/project/hummingbird?ufh
Revit Versions Supported - 2015 and 2014
Development – Private released to public at no cost
Operation – Exports grasshopper to csv (comma separated value) file which is
then imported into Revit.
Grevit – Maximilian Thumfart
http://grevit.net/
Status - Active
Latest Update – December 2014
Download – http://grevit.net/
Revit Versions Supported – 2015, 2014
Development – Private released to public at no cost
Operation - Sends data directly from Grasshopper to corresponding Revit plugin.
ggRhinoIFC and ggRevitIFC - Geometry Gym
http://www.geometrygym.blogspot.com.au/search/label/Revit
Status - Active
Latest Update - April 2015
Download – http://www.geometrygym.com/downloads
Revit Versions Supported – 2016, 2015, 2014, 2013, 2012
Development – Commercial, Free access for Academic Use
Operation – Utilizes openBIM file format IFC as an intermediate file exchange.
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Chameleon – Hiroshi Jacobs
http://lmnarchitects.com/tech-studio/bim/superb-lyrebird/
Status - Inactive
Latest Update - June 2013
Download – Link Inactive
Revit Versions Supported –2014, 2013
Development – Private released to public at no cost
Operation - Sends data directly from Grasshopper to corresponding Revit plugin.
CASE Tools – CASE
http://lmnarchitects.com/tech-studio/bim/superb-lyrebird/
Status - Active
Latest Update – not known
Download – not known
Revit Versions Supported – not known
Development – Commercial
Operation – Understood it uploads data to server which can then be
downloaded to Revit.
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Functionality Provided
A quick summary of plugin evident components and functionality is now
outlined.
Lyrebird
Lyrebird has a single component that can take as inputs location point,
Adaptive Component point locations, Curves, Orientation Vectors and Face
relative orientation vectors.
Hummingbird
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Hummingbird has grasshopper components to generate : Adaptive
Components, Floors, Grids, Levels, Walls, Beams, Columns, Families, Lines, Loft
Forms, Mass Families, Rooms/Areas, TopoSuface
Grevit
Grevit has grasshopper components to generate: Adaptive Components,
Columns, Curves, Extrusions, Family Instance Placement, Grids, Hatches, Levels,
Walls, Rooms, Floors, Text Notes, Topography points and Parameters. It seems to
have place holders for Structural objects which are not apparently developed
yet.
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Geometry Gym
The Geometry Gym Revit components are able to generate: Grids, Levels,
Materials, Material Layers, Profiles including Regional Catalogue and standard
shapes, Architectural and Structural Generic Model Family Types, Column Types,
Floor Types, Structural Framing Types, Wall Types, Direct Shape Instances,
Adaptive Components, Family Instance Placements, Columns, Floors, Structural
Framing and Walls. Also parameters of types Text, Integer, Number, True/False,
Length, Area and Volume.
Chameleon
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Chameleon has primarily one component to generate Revit Adaptive
Components, one to set Parameters and two others to extract data from Revit.
Case
Unfortunately at the time of compiling this handout I was not able to get access
to the Case plugin, and thus have not been able to test it. From details on the
blog of a Case staff member, it seems it has components to generate Grids,
Levels, Adaptive Components, Floors, Hosted Objects, Family Instance
Placement and ability to set parameter values.
It is presumed this plugin would perform very well as a comparison to the others
included.
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Adaptive Components
Generation of adaptive components is one common capability of all the plugins
considered and thus is a good place to start comparisons.
Lyrebird
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Hummingbird
Grevit
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Geometry Gym
Chameleon
All work successfully at generating the adaptive component elements except
Grevit. In this test case
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Floors
Floors have more complexity to them and I tested a range of inputs for this,
including a polyline outline, a polyline outline with an internal opening, a
polycurve (arc) segment perimeter and a nurbs perimeter. Note Revit doesn’t
accept a single closed perimeter curve so either the plugin or user must split the
curve into at least two in this case. Note also that Revit really only accepts
degree 3 curves so it’s possible a rebuild is required in this case.
Lyrebird
Lyrebird won’t create floor objects, but it does have an input to create model
curves for the user to manually use. Unfortunately I couldn’t successfully create
the model curves with my attempts to use this.
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Hummingbird
I had partial success with Hummingbird with my test cases. It created the
polyline perimeter floor fine, it did not create an internal opening. The polycurve
test worked great. To achieve a nurbs perimeter I had to split it in grasshopper
prior.
Grevit
Grevit created a polyline perimeter floor, but errors caused the process to abort
for all other tests. The floor was at an incorrect scale meaning geometry should
be manually scaled prior to feeding into Grevit.
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Geometry Gym
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Columns
Generating Columns was tested in the plugins offering that functionality. The
lack of preview in hummingbird and grevit can make checking and trouble
shooting a more difficult process in elaborate setouts.
Hummingbird
Hummingbird seemed to fail to generate structural columns, but can place
architectural columns. Also no apparent ability to generate a sloping column.
Calculation of orientation angles required by the user.
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Grevit
Grevit creates the structural columns, but has no ability to orientate them.
Geometry Gym
Works well with orientation. Ability to use the catalogue profile with different revit
naming convention would require user adjustment.
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Pros and Cons
Lyrebird
Grasshopper Component Revit version isn’t “sticky” and has to be manually
nominated each session.
Not much feedback about failure to create objects.
Hummingbird
Tracks objects created but can’t update changes to existing.
Cancel button is provided to abort Revit generation which is not found in other
plugins.
Can be a little tedious to generate lots of different nature objects as each
generates a separate file which needs to be manually picked for import in Revit.
CSV (comma separated value) file provides ability to record what was sent.
Revit and Grasshopper can be used in isolation by independent users.
Revit undo only removes one element at a time.
Grevit
Offers a lot of functionality.
A single error seems to abort the generation of all elements.
Having to scale geometry inputs to feet isn’t ideal in terms of managing this and
risk of mistakes.
Geometry Gym
Offers a lot of functionality.
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A log of model transferred can be stored in the openBIM IFC file.
Can also be used to exchange to other software including Tekla and Archicad.
Offers preview of objects in view port, but requires families etc to be defined in
Grasshopper (it is expected that importing families from a Revit project/template
will be provided soon).
Revit and Grasshopper can be used in isolation by independent users.
Chameleon
Seems to be an abandoned project and doesn’t load beyond Revit 2014.
Conclusion
Hopefully this handout with lab data can help inform those considering
Grasshopper to Revit work flows about the differing functionality and operation
the alternative plugin developers are offering.
It is by no means a comprehensive or exhaustive comparison, but every single
user is likely to have a near unique set of requirements and expectations. If a
free plugin offers exactly the functionality needed then that a great result. The
commercial plugins are likely to offer more comprehensive functionality with
superior access to support and improvements.