Support for IfcStructuralSurfaceMember

[berndhahnebach]

Hi Thomas,

Tried to import the shape of a IfcStructuralSurfaceMember which is a IfcFaceSurface from tons of IfcFaceOuterBound. It is a IfcTopologicalRepresentation not IfcShapeRepresentation. It seams create_shape of IfcOpenShell does not support such entries. If been playing a bit. If I change some entries and add it to the IfcSite the shape could be imported. Find the file here: http://forum.freecadweb.org/download/file.php?id=7552 Is there any chance IfcOpenShell is gone support such entries?

bernd

Python 2.7.8 (default, Jul  4 2014, 13:08:34) 
[GCC 4.9.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ifc_wrapper
>>> i=ifc_wrapper.open("/home/hugo/Desktop/1549-IfcStructuralSurfaceMember.ifc")
>>> ss=ifc_wrapper.create_shape(i.by_id(1549))
>>> ss
''

[aothms]

Hi Bernd,

Currently IfcOpenShell does not support the IfcTopologicalRepresentation, it doesn't seem to be used much except for some structural engineering apps using it to define the vertices and edges of structural schemas. If you can provide me with a bigger set of test files, preferably from different applications, that use IfcTopologicalRepresentations for 3d visual geometry, I will definitely think about it, but for now it is not very high on my list I must admit.

Kind regards,
Thomas

[berndhahnebach]

Hi Thomas,
thanks for your answer. That is exacly where the file came from, structural engineering apps. I'm thinking of extending the importer of yorik to analytical modells. The geometry shapes are the base of anything in this regard. That is why I'm only interested in IfcStructuralCurveMember and IfcStructuralSurfaceMember. There is even no Viewer for such modells out there, non !!! You need to have one of the very expensive structural engineering app to even view the geometry of the IfcStructuralMember.

I set up a repository at https://github.com/berndhahnebach/Ifc_StructuralAnalysisView Find some files and informations there. I could provide more files. Let me know what kind of files you need. Simple ones, more complex ones ... All of them are exported with one application (AxisVM). I may could provide exports of other applications as well, but that will take more effort. If you would really start to on this I would provide them.

Would be great to see IfcOpenShell supporting IfcStructuralCurveMember and IfcStructuralSurfaceMember.

Kind regards bernd
PS. Ahh FreeCAD in an early development status provides FEM calculations too (http://forum.freecadweb.org/viewtopic.php?f=18&t=6992&start=10#p60806)

[aothms]

Hi Bernd,

It has been a (long, long) while. Not sure if you are still pursuing this. With the latest commit in the svn repo [1] it is now possible for IfcOpenShell to extract this information. Both for shape- as well topological representations lines can be emitted, as long as the correct settings are specified (INCLUDE_CURVES, EXCLUDE_SOLIDS_AND_SURFACES). The create_shape() function has been given an additional optional argument to specify a representation explicitly, which is otherwise derived from the settings. For example to get the Axis representation in case of a wall (still INCLUDE_CURVES must be set in that case).

Also ccing @yorikvanhavre

[1] https://sourceforge.net/p/ifcopenshell/svn/348/

Kind regards,
Thomas

[berndhahnebach]

Hi Thomas, what a pleasant news. :-) . I have put it on hold. But there is currently some heavy development in the regard of FEM in FreeCAD. As soon as the FEMWB in FreeCAD is sufficient for some basic calculationts I will start again trying to import my calculations by using Ifc_StructuralAnalysisView. If I have a minute I am gone test it and report back.

Kind regards, Bernd.