The gasballoon effect is not the same as P4's slight rounding. Here's a comparison... I made the object in Amapi, saved it separately as 3ds and OBJ. Rendered it in P5 using the old P4 renderer versus the new Firefly. I didn't bother to make the camera angle agree, but you can still see the diff. In the P4 renders, slight corner-rounding. In P5FF, pure gasballoon!
My python page
My ShareCG freebies