BIM Automation

A Computational BIM workflow with Excel, Houdini, Grasshopper and ARCHICAD

I’m Vignesh Kaushik. I curate and write articles on Thank God It’s Computational to help architects, designers, and urban planners leverage cutting-edge technologies on AEC projects.

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This Computational BIM workflow showcases how Excel could be as a Parametric Model Interface for SideFX Houdini that generates MRT Station Design in Native BIM in ARCHICAD.

This automated workflow allows Architects to iteratively prototype Singapore MRT Station layouts in BIM in a matter of minutes, using just an Excel Spreadsheet. It saved my team a ton of rework while designing the right fit for the underground station box in 2017.

Using this parametric script in SideFX Houdini, one can create any type of underground MRT station within the guidelines set by the Land Transport Authority (LTA) of Singapore.

A few types of Singapore underground MRT Station design

Since the team involved designers who were not familiar with the parametric design process, I had written custom scripts that will enable non-computational designers to use a simple Excel file to control a parametric model and automatically generate a native BIM model in ARCHICAD.

Excel - ARCHICAD Automation workflow

This workflow involves MS Excel as the parameter input interface for SideFX Houdini, which is used as the Parametric Engine that generates the lightweight BIM model. This lightweight model is then imported into Rhino/GH that then uses the GH-AC Connection plugin as an interoperability tool for creating a native BIM model in ARCHICAD. This workflow is entirely automated using a simple .BAT script that takes less than 60 seconds for the final BIM model to be generated in ARCHICAD.

I know what you’re thinking - why not use Grasshopper to write the parametric script also? Yes, that’s also possible. However, in this case, I wanted to explore using a much more advanced parametric engine like SideFX Houdini and decouple the parametric and interoperability script development.

Excel Parameter Input

Parameters in a typical undeground MRT station

• The .BAT file enables the conversion of Excel into .CSV file using another .VB script.

• SideFX Houdini is then launched that runs the parametric script that creates the lightweight BIM model using the parameters from .CSV file.

• This lightweight BIM model is then imported into Rhino/Grasshopper as input for the H-AC interoperability script that recognizes that new geometry has come into the model.

• It then pushes the light-weight BIM model to ARCHICAD as native elements including walls, floors, openings, doors, furniture objects, etc.

@ECHO OFFexcel-to-csv.vbs Parameter_Input.xlsx Parameter_Input.csv

ECHO Begin Excel to Houdini Automationstart happrentice Generic_MRT_Template.hipnctimeout 40taskkill /IM "happrentice.exe" /F

ECHO Begin Houdini to Rhino/GH Automation

ECHO Begin Rhino/GH to ARCHICAD Automation

cd C:\CRLE_MRT_Automation

"C:\Program Files\Rhinoceros 5 (64-bit)\System\Rhino.exe" /nosplash /runscript="-_import MRT_Output.obj enter -grasshopper editor load document open Generic_MRT_Template.gh _enter" "Generic_MRT_Template.3dm"

The entire workflow is recorded in the video below.