How to control which part of a an object (trees) are visible when exporting to IFC?

[AdrianL]

I've edited tree models which I think look good yet remain low-poly in 2D plan, as a realistic "2D cutout" and as 3D polygons. (Using nested 3D symbols on different classes within "3D graphics")

 

The 2D cutout mode looks great in Lumion/rendering/section but not in IFC export since alpha mask are disabled. Therefore I've added a 3D low poly version of each tree on a separate class.

 

This works great in VW/Lumion. However, when I export to IFC every object within "3D graphics" is visible, including those on tags that are turned off. I've also tried classifying these objects as different level of detail, but this doesn't seem to affect IFC export. Furthermore, the entire tree object turns green, ignoring the colors I've assigned inside "3D graphics" editing.

 

How can I hide parts of an model when exporting to IFC? (and preferably maintain assigned fill in VW)

Thank you!