Union Solids

Hi Conny,

Can you elaborate on what you want to do? Solids by nature are enclosed 3D regions with volume, so I'm not following how you visualize performing a Boolean union of "surface area instead of volume".

Dear Bentley,

Please be informed that for instance,have place 2 forms where one of their edge overlap and interface with each other,thereafter we have union this 2 forms become 1 single form,we have check the volume after union and found it been sum/total up but the surface have not been sum/total up.

Kindly assist.

regards,
Conny

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. 

Dear Bentley,

Noted,kindly assist how we go about it if we would like the union form/solid resulting their surface area can be sum/total up?

regards,
Conny

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.