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[IfcOpenShell] obj2ifc.py / file.create_entity() - Doesn't work with IfcElementType?

1. V by vinnividivicci on 4 Nov 2022, edited 5 Nov 2022 #

   Hello,

   I'm working on a project to generate IfcElementTypes from Obj files using IfcOpenShell.

   Using the obj2ifc (meshlab) version works for me to create IfcElement instances (IfcFurniture for example) but when I try to create an IfcElementType (like IfcFurnitureType), I get the following error:

   
   Traceback (most recent call last):
   
     File "C:\Users\vince\Desktop\test\obj2ifc-meshlab.py", line 157, in <module>
   
       obj2ifc.execute()
   
     File "C:\Users\vince\Desktop\test\obj2ifc-meshlab.py", line 80, in execute
   
       product = self.file.create_entity(
   
     File "C:\Users\vince\anaconda3\lib\site-packages\ifcopenshell\file.py", line 284, in create_entity
   
       e[idx] = arg
   
     File "C:\Users\vince\anaconda3\lib\site-packages\ifcopenshell\entity_instance.py", line 218, in __setitem__
   
       method = self.method_list[idx]
   
   IndexError: list index out of range
   

   I suspect it's because either the "create_entity" function doesn't work for IfcElementTypes only for "instances" or that I'm not providing the correct additional arguments to the function.

   Any insight on this @Moult ?

   Thanks!

2. M by Moult on 4 Nov 2022 # +1 votes

   If you just replaced "IfcBuildingElementProxy" on L81 with an IfcElementType, it won't work because it's assigning attributes that exist on IfcBuildingElementProxy but don't exist on types. For example, types don't have an ObjectPlacement and nor do they have a Representation.

   Here is a slightly more agnostic implementation:

   
   ifc_class = "IfcBuildingElementProxy" # Or a type will work too
   
   product = ifcopenshell.api.run("root.create_entity", self.file, ifc_class=ifc_class, name=mesh.label() or self.basename)
   
   if product.is_a("IfcProduct"):
   
       product.ObjectPlacement = self.placement
   
   ifcopenshell.api.run("geometry.assign_representation", self.file, product=product, representation=representation)
   

3. D by duncan on 4 Nov 2022 #

   Added [IfcOpenShell] to the post name so people can more easily see what posts they could be interested in reading

4. V by vinnividivicci on 5 Nov 2022 #

   Thanks for the response guys, I'll give it a try.

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