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xBimTeam / XbimGeometry

XbimGeometry contains the CLR interop libraries and the c++ engine used to compute the 3D geometry of models.
https://xbimteam.github.io/
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Incorrect reproduction of geometry in Xbim Xplorer #250

Open mrBuBeN opened 5 years ago

mrBuBeN commented 5 years ago

Hello. I downloaded a precompiled installer of Xbim Xplorer and also have cloned xBIM WindowsUI repository. Then I opened ifc file by both of them. I have an equal results:

image.

But when I opened this file using Solibri I got a different result image.

Can somobedy explain the reason of this result? And what should I change in the code so that the results become similar to Solibri?

The file can be found at http://openifcmodel.cs.auckland.ac.nz/Model/Details/208

andyward commented 5 years ago

Confirmed still an issue in 5.1.254.0.26 Geometry. No warnings generated

It looks like the geometry is there but obscured by a bounding bx

guenter1holzeder commented 4 years ago

I don't think this is a geometry engine issue. The bounding box of the IfcSlab is overlapping the roof. If you delete the reference to the bounding box in the IFC file you will get a valid result.

Maybe this is a building scene issue !?

grafik

CBenghi commented 4 years ago

I've looked at the code and I think it is a geometry issue. One with a non-trivial solution, btw.

The way we decide if the geometry gets meshed or not depends on the properties of the IFCSHAPEREPRESENTATION.

To work nicely with old models everything that has an empty RepresentationIdentifier is considered valid for meshing. This should not be done when, (like in this case) we have both the bounding box and the actual geometry, however there's no information in the geometry cache that allows us to quickly discriminate the RepresentationIdentifier to discard, which I think is an intrinsic problem with the geometric cache.

See https://github.com/xBimTeam/XbimGeometry/blob/8c5db8c8ea02662bfac6639b6136d478471b62cf/Xbim.ModelGeometry.Scene/Extensions/IIfcRepresentationExtensions.cs#L17