Following codes find bottom face of groups. when groups are closed loop problem will happen. You can see open loop and closed loop in photo.
temp_grp = Sketchup.active_model.entities.add_group grp.entities.grep(Sketchup::Face) do |f| temp_grp.entities.add_face f.vertices if f.normal == [0, 0, -1] end temp_grp.material = "red"
I changed group position to show problem. Can you help me to know why it happen and how can I solve this problem?