Monday, 29 November 2010

Grasshopper IFC generation New Features

New features for extruding and remapping (arraying) building information models (BIM) in Grasshopper, exporting using IFC.
YouTube demonstration uploaded shortly.

Monday, 15 November 2010

Grasshopper generating IFC Update

Thanks to Scott Davidson for the gothic inspiration and a great example of Grasshopper Generation and the ensuing improvements for exporting from Rhino/Grasshopper to IFC (can be imported by BIM software such as Revit, Archicad, Digital Project, Microstation, Tekla etc etc).

IFC2x4 is anticipated for formal release next year, which includes NURBS representations and should enable Rhino/Grasshopper models to be exported with greater accuracy and with greater ease.  Until then, IFC2x3 does provide means and ways to represent shapes and forms created by nurbs, and this blog post will demonstrate some of them.  Note most software does not recognize or work with all aspects of IFC, so approximations such as the first for faceting the brep may be your only option.

The first shape representation is using a faceted brep, effectively meshing the surface.  Unless your original shape is a faceted brep (with planar faces and straight edges), there will be a loss of detail, but you can control the refinement of the meshing process (introducing more faceted faces).

Grasshopper Definition    Generated IFC Data

Theoretically it's not necessary to approximate the form with a faceted brep if you can generate it using processes and shape representations within the IFC specification.  This includes extrusion and boolean operations which can be used to form this vault.  In practice, it seems very few BIM software and IFC viewers acknowledge or are capable of these operations, so you may be forced to use the faceting approximation.  Please test these models with your favorite IFC software and feel free to post your observations as comments.

Most programs comply with extrusion, here's Archicad importing this model:

Grasshopper Definition    Generated IFC Data

I've struggled to find even an IFC viewer to successfully display this model, but there's no warnings of non-compliance.  The boolean operations should work with a rhino model absolute tolerance set to 0.01

Grasshopper Definition    Generated IFC Data

Please post any comments with software you can or can't open these models with.  If you've any particular shapes you'd like to export that aren't successful, please get in touch and I can help advise.

Instructions for getting started with the IFC plugins are found here.

Monday, 8 November 2010

Grasshopper generating IFC

Here's the first demonstration and example files for generating IFC from Grasshopper using the Geometry Gym plugin.  This is just the beginning.  IFC can be read by popular software such as ArchiCAD, Digital Project, Revit, Tekla etc etc.  Download the plugin from

Please try for yourself, and report all ideas, suggestions and problems.

Here's the Rhino file for the tower massing:  Rhino Model
Here's the Grasshopper definition:  Grasshopper Definition