Importing IFC model generated by Rhino3d/Grasshopper3d

[Anonymous]

Hi All,

I've been developing software tools to enable IFC model generation in generative/parametric modelling Grasshoper3d and Rhino3d.

You can learn more about the project at http://geometrygym.blogspot.com

I've downloaded ArchiCAD to test the files being imported, and had some success. I can't get it to recognize this sample with a stair tread using a BooleanResult shape representation (which should be similar to SEO from what I can gather).

This might be an issue with the IFC data generation, but it's difficult to find a forum to discuss/review this, so I thought I would post here.

If anyone has an interest in trying and testing the tool, please get in touch. Any ideas/suggestions for improvements will be implemented as quickly as possible.

Thanks,

Jon

[Anonymous]

Following up with an example image of Grasshopper3d IFC generation

[Link]

Have you tried viewing it in a pure IFC Viewer, like Solibri, to see what it looks like before ArchiCAD imports it?

Cheers,
Link.

[Anonymous]

Hi Link,

Thanks for the reply.

I've tried viewing the model in Solibri, Nemetschek and Constructivity. None of them reproduce the shape as intended.

It's likely there's a fault in the file, but it complies with the standard as far as I can tell. It may require that Archicad and other software need the openings implemented as Opening Elements, but I'd prefer to get the voids in the shape representation if possible (if I generate multiple treads, I don't want to generate all associated opening elements.).

I can't find any example IFC files using IFCBooleanResult, and I tried exporting SEO from ArchiCAD but it was ignored in the export (I found another post discussing this).

I don't know any active IFC disucssion forums, so thought I'd post here.

I just posted a demonstration of the importing from Grasshopper to Archicad, you can view it here: http://geometrygym.blogspot.com


Cheers,

Jon

[Erika Epstein]

Archicad and other programs reads the model based on IFC classifications. If you are not seeing your model in the IFC viewer as you feel it should, the translation from your program to IFC should be reviewed.

[Anonymous]

Hi Erika,

I'm doing everything I can to comply with the IFC specification.

The issue is I can not find any example files that use boolean operations other than half spaced solids to compare with.

Even trying to export an object with SEO applied in Archicad seems to ignore this geometric change. Most other programs seem to export faceted breps rather than the process to extract say a cylinder from a block. Of course the faceted approach is an approximation, which is an option available for my users to output but it seems difficult to find software that conforms to this aspect of the IFC classification (I'd gladly be prooved wrong).

If anyone has any examples or advice relating to this, I'm most grateful.

Thanks,

Jon

[Anonymous]

It looks like you are in relatively uncharted territory. Most IFC support seems to be to do the easy bits and interpret all the rest as BREPs. I suspect that this is what you are running into. Your IFC may be fully compliant but just uses features that are unsupported in other software - at least in their generic translators.