Union Solids

Question

Dear Bentley, 
 Kindly assist how to union the surface area for 2 solid instead of their volume? 
 regards, 
 Conny

Steve Cocchi · Accepted Answer

Ah... I see. Yes, what you are describing is correct. The reason you are seeing this difference is that when any type of Boolean operation is performed on a Form, whether a Union, Cut Solid, etc., that operation generates a Feature on that Form (first selected for a Union). With a cut the result is fairly straightforward since material is being removed from a single entity, but when performing a Union you are essentially adding the mass of two individual objects. So what you should see are the Areas and Volumes for both the combined Forms listed in the Building Info > Quantities tab. 
 
 There isn't a single total shown for Area like there is for Volume, but I think this has always been the case.

Steve Cocchi · Answer

The simplest method would be to first select the Boolean Form, pick the MicroStation "Measure Area" tool, then accept. That should give you the combined surface area.