IFC import geometry unwieldy

[Matthew Johnson]

When importing IFC (from Revit Structure) beams and columns generated from BREP (ie more complex than a flat extrusion) the geometry created either in Morph or Object format is of such a high polygon count that navigating the resultant model is impossible.

Does anyone know of a method to reduce the level of detail in the imported objects and profiles so that the intent (eg steel I beam) is maintained without the massive polygon count being generated?

Would also be useful to know of any methods for rationalising Morphs created from imported objects.

[Laszlo Nagy]

Matthew, you can either attach a ZIP file to a post (limited size) or give us a link to a file in Dropbox or something similar.

[Matthew Johnson]

Laszlo,

The attached screen capture shows the differences in polygon count between Solibri and ArchiCAD.

Some members, such as the I beam (running lower right to top left), seem to have a similar number of faces in both programs. Solibri identifies this as a beam.

Other members, such as the CHS struts with end plates, have far more polygons in ArchiCAD.

However, the model in Solibri is navigable with ease and shows no delays whereas navigating the model in ArchiCAD is very slow.

PS: Working on getting a Revit file from the engineer with just a couple of members in it for testing.

[Laszlo Nagy]

I don't have a solution so there is not much I can say, besides that you should report this through your local reseller.

[Anonymous]

Matthew,

I have had similar problems with Revit beams, columns and slabs that have cuts being imported as objects rather that beams and columns, with angled bracing being especially problematic.

My solution to the problem is to have a structural model (controlled by me) which I hotlink into the main project file. This file started as an imported file from revit and I went through the file and replaced the imported members that were blocks with beams and columns. When I now receive an updated structural model I reference this into the structural model and make required adjustments where the model differs from my model.

By doing this I have a model that is quick to navigate and section generation times are minimal.

Attached are a couple of views from my current project, I can navigate views in real time and sections and elevations only take a few seconds to regenerate.

Regards,
Scott

[Anonymous]

As Laszlo has indicated, if the revit export has exported a primitive object with lots of polygon faces, it's difficult to reverse engineer the intelligent object back out from it.

The Revit IFC exporter is openSource, so it might be possible to "improve" the export with a sample object to test with. I've been developing an IFC importer for Revit including IFC4 (http://geometrygym.blogspot.com/search/label/IFC) and I am also trying to get a chance to start working on an independent exporter too.

It should not be necessary to manually substitute objects each time a model is submitted, but certainly in this case (and Scott's by the sound) a higher quality IFC export would go a long way to help this.

[Mats_Knutsson]

We have another "problem" regarding the plan view of columns coming in (merge ifc) as objects (projection cut as A in attached image). To show the correct plan cut I change the "columnobjects" to morphs and then I can choose cut only (or with overhead), (B in attached image) as projection. Issues like this create the need for 2D dwg for the drawing production.
3D is fine