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.