Terrain texture is discarded when exporting to IFC

aogino

Textured terrain generated using BlenderGIS loses its texture when converted to ifc using BlenderBIM.
The project is in IFC4 and the class I chose for the terrain is IfcGeographicElement.
Before exporting to Ifc:

After exporting to Ifc:

Andrej730

Does this ifc object has ifcsurfacestyle with that texture or it's just a blender material?
If it's just a blender material it won't be saved to ifc - you'll need to create an IfcSurfaceStyle, assign it to this object and assign the texture to that style.

aogino

@Andrej730 said:
Does this ifc object has ifcsurfacestyle with that texture or it's just a blender material?
If it's just a blender material it won't be saved to ifc - you'll need to create an IfcSurfaceStyle, assign it to this object and assign the texture to that style.

I get the idea, but I think I already have a ifcsurfacestyle applied :

When I export it to ifc and open it in another viewer i don't see any texture still
I think this only imports the texture from its path in blender

Andrej730

What's the other viewer?

I think this only imports the texture from its path in blender

So loading the same .ifc file to Blender loads it with the texture?

Can you please share .ifc file or part of .ifc file that has information about this surface style and texture?

aogino

The viewer is BIMVision.
No, loading the same .ifc file to blender does not preserve the texture. But loading the .blend that contains the ifc project does. The image used for texture needs to be in the same directory as the .blend file.
I've put the files I'm using in this zip :

Ace

You need the Ifc and Reference image (texture) to be near each other
1) Save the object as an IfcGeographic element
2) Create a material
3) Create a Surface style
4) Reference the texture, set the UV mode to generated (this might be technically incorrect)
5) Apply the surface style to the object
6) save the IFC

I've linked them in the example you provided (just the Ifc and texture no blend file needed)

Andrej730

Any ideas if BIMVision supports textured styles in general? Since it still loads object without a texture even with generated UV.

tom_ccc

Will IFC files support texture passing in the future?

aogino

@Ace said:
You need the Ifc and Reference image (texture) to be near each other
1) Save the object as an IfcGeographic element
2) Create a material
3) Create a Surface style
4) Reference the texture, set the UV mode to generated (this might be technically incorrect)
5) Apply the surface style to the object
6) save the IFC

I've linked them in the example you provided (just the Ifc and texture no blend file needed)

I've reopened this file in Blender 4.1 and I don't see the texture - I've followed the steps you provided to check and I've found that everything has been already set, but no texture appears.

aogino

@Andrej730 said:
Any ideas if BIMVision supports textured styles in general? Since it still loads object without a texture even with generated UV.

No idea, but can you confirm if the texture appears for you in Blender when using @Ace's data ?

Andrej730

@aogino said:
No idea, but can you confirm if the texture appears for you in Blender when using @Ace's data ?

Yes, loading .ifc file from Ace works for me on the latest build. It also works if I reproduce those steps myself using object from original .blend file.

If you're opening it in Blender 4.1, then it may be some bug in older BBIM version - current build supports only Blender 4.2+.

The problem with that generated UV method - it works but may work unexpectedly since it discards the original object UV. There actually was a method in BBIM for saving UV to IFC but it got lost when we were reworking UI, I've updated it and it should now work for saving UV for objects that come not from IFC, see commit description - https://github.com/IfcOpenShell/IfcOpenShell/commit/ef835e43b8187bf4905bd33a450e4ceebbbc7e38

tlang

@tom_ccc do you mean saving textures as described here?

aogino

@tlang said:
@tom_ccc do you mean saving textures as described here?

I think the link is broken