IFC Entity inconsistency in walls in ifc export

[mariaZW9XM]

Hello there.

I did an IFC export  from our revit file in IFC 2x3 Coordination View 2.0 and we got some inconsistency in the IFC Entity. We got 4 walls with different IFC Entity as IfcWall ( see 1st picture) wich are different from the rest of walls IFC Entity as IfcWallStandardCase (see 2nd picture). They are the same family. And I also try with to have the same walls with different elements that can affect this, but then the IFC Entity is correct.

My questions are:

Do you know why we get this type of inconsistency ? Is this usual?

Do you know how we can fix it? 

[MichaelOrtmann · Accepted solution]

if it may still help you:
I believe it's because of the difference in the geometry between extrusion and boundary representation. I suppose the wall with the boundary representation has some cutouts where it joins the other walls.

See the IFC definition for the StandardCase:

The IfcWallStandardCase defines a wall with certain constraints for the provision of parameters and with certain constraints for the geometric representation. The IfcWallStandardCase handles all cases of walls, that are extruded vertically:

• along the positive z axis of the wall object coordinate system, and
• along the positve z axis of the global (world) coordinate system

and have a single thickness along the path for each wall layer, i.e.:

• parallel sides for straight walls
• co-centric sides for curved walls.

This article might help you with overwriting the IFC Type (Although you should probably check the definition of both Types first to decide if it is the right choice to do so).