ifc export problem

[Anonymous]

Hello, I am trying to export a model to IFC, but when I open the IFC fyle I see that some walls exports as IfcWall but others exports as IfcWallstandardCase, in the mapping I have configurated as IfcWall. Futhermore, I have tried to change it with the parameter IfcExportAs but it does nothing, and also if I specify the IfcExportType paremeter doesn't modify it either. 

Thanks for the help

[Marvi]

Have you tried use the IFC exporter from the Autodesk App Store? 

https://apps.autodesk.com/RVT/en/List/Search?isAppSearch=True&searchboxstore=RVT&facet=&collection=&...

[Anonymous]

Yes I've tried but I have the same problem.

[Lance.Coffey]

Thank you for the question @Anonymous!

I’m seeing a similar thread on this topic here: Changing IFC class for system families

In the thread above, it looks like the value was being controlled by the IFC Version that was being exported:

2x3 Coordination View 2.0 -> IfcWallstandardCase

IFC4 Reference View        -> IfcWall

In my testing (with a new sample model - attached) I am seeing similar results.

If this doesn’t work for you, could you reply with a sample model for further testing?

[Anonymous]

Hello, thank you for answering.

In my case in the version 2x3 I have some walls as IfcWall an others as IfcWallStandarCase, if I export in the version 4 all the walls are IfcWall. But I have to export it in 2x3 and I need all the walls as IfcWall, and if it's not possible I would like to undestand why some walls exports as IfcWall and others don't.

[Lance.Coffey · Accepted solution]

I found the following definition from Building Smart for IFCWall with IFC2x3, that may answer why some of these walls are exporting differently:

IfcWallStandardCase  used for all occurrences of walls, that have a non-changing thickness along the wall path and where the thickness parameter can be fully described by a material layer set. These walls are always represented geometrically by a SweptSolid geometry, if a 3D geometric representation is assigned,

IfcWall  used for all other occurrences of wall, particularly for walls with changing thickness along the wall path (e.g. polygonal walls), or walls with a non-rectangular cross sections (e.g. L-shaped retaining walls).

Looking at the provided sample model, I’m seeing that 11 of the walls are exporting as IfcWallStandardCase, and two are exporting as IfcWall.

Here is a screenshot showing two of these walls:

From what I’m seeing, in the example above the floor cutting into the wall on the right, is causing that wall to have a sufficiently varying thickness to be output as the non-standard IfcWall (removing that floor then re-exporting changes the output so that both walls are output as IfcWallStandardCase.