The house volume is selecting as a solid but we want to be able to select faces for face sets, one set for the house walls, the other for the heater (the void in the middle). Any tips appreciated
Project Link: https://www.simscale.com/projects/arnold1/wintry_morning_ii_from_iges_cad/
It seems that you got it working using the IGES file?
Make sure you are in Pick faces mode before the selection , otherwise you would not be able to select the faces.
Hope this helps. If not, please let us know