Solid breaks apart after union

 From:  bemfarmer
7582.6 In reply to 7582.4 
Thank you for the explanation J.

Here is a wireframe view of the two solids sitting next to each other. (There is a wireframe shortcut script.)
Replace the bottom prisms with one larger prism. The bottom prisms can be deleted face by face.
The 2 large circles are to be deleted from the top face of the new prism. Then join everything remaining.

- Brian




I have not tried Michael's methods.

EDITED: 2 Sep 2015 by BEMFARMER