Sorry Shotster -- I should have said the screen shots were from
Silo 3D. (A really good companion tool to C3D, or any 3D program really.)
I believe that
Blender's bevel/chamfer tool is pretty good. So you could export to some file format Blender reads (e.g. OBJ) and then make the change (after struggling with Blender's various UI quirks ... just how do you select something? Oh right, you need to be in edit mode...) and then bring it back. Blender is free, small (<20MB), and runs well on almost any hardware. It's a pain in the ass to use most of the time, but its amazing functionality (and free-ness) makes it one of the first programs I install on any computer I use.
Wings3D has the feature and is also free. It's a similar tool to Silo 3D (i.e. a dedicated modeler). Its UI is quirky, probably a bit harder to figure out than Silo 3D (which is about as approachable as Cheetah 3D) but not as nuts as Blender.
Warning: I've had trouble getting it to work on Intel Macs (and have stopped using it :-( ).
Final Note
Almost any 3D modeler is going to have to get used to using multiple programs to achieve a specific desired result. If you wait for your favorite program to get some specific feature you need, you'll discover that some other new feature will have been added to a rival program. Even the big boys (like 3DS Max) don't do everything, or do some things poorly (Silo 3D -- a $159 program -- is widely used by folks who have licenses for Max, XSI, and/or Maya).
One of the first 3d models I built (back in 1990
) was a chess set. I wanted it perfect. I was using Strata 3D 1.4.2, which didn't have booleans ... so I couldn't cut a slot in the bishops' heads. I ended up using Minicad just to model the heads of the bishops. The rooks ("castles") were also impossible to do without booleans, so they got done in Minicad as well.
Finally, I couldn't figure out how to put a seven pointed crown on the queen's head (Strata did actually add mesh editing tools shortly after I finished the model). In the end I wrote a program (using hypercard) that exported a Swivel 3D script that when opened in swivel 3D assembled, polygon by polygon, a perfect seven pointed crown).
So, to build a simple chess set it took three 3d programs and HyperCard.
Edit: hey I found a copy of the rendered chess set