Hi Paul,

If the Fillet command fails to work on parts of your geometry - you can try this (more manual) work around:



http://moi3d.com/forum/index.php?webtag=MOI&msg=4607.5


Basically, you would create a gap at the edge location by which you would construct the rounded-over corner surface with the Blend tool and other construction methods.
The gap can be created by using Boolean Difference to subtract a the result of a Swept operation. The resultant surface edges are (matched) and then Blended.

It's not a straight-forward and easy procedure since one: some surface edges on your geometry simply need to be addressed for error, and two: some edge curves on the gaps have to be Merged or Trimmed to be matched, and three: the Sweep object used to Difference your geometry to make the gap may have overlapping kinks and can't readily be used unless rebuilt themselves.

This is like using MoI brand duct tape to fix an inherent problem in your geometry, but can keep you from pulling out all of your hair when your stuck trying to get that Filleted edge you desire.