I used Ray Dream Studio 5 for awhile, I remember it making quite a lot of really bad gemetry, typically it would have a polygon with a edge common to two others, just like what you show, as soon as you moved it the slightest bit a hole would open. It had a lot of other problems too, plus there was a lot of problems seeing what you were actually doing, I don't know if 5.5 is/was any better, and I never tried Canorama (?) it's replacement.