Hi John, MoI's filleter is not really going to be able to handle those spots where you've got surfaces that are partially tangent to one another but then further along come to a crease.

For MoI's filleter to work those surfaces are going to need to meet at more of an angle to one another throughout their entire common edge.

Here is one of those spots that I'm talking about:



In this version, I have adjusted the top shape inward slightly to avoid that situation and make a more continuous crease along the shared edges between the surfaces:



This version can now be filleted throughout (using v2 beta Sep-21 version):



Result 3dm model is attached as 002_filleted_3dm.zip .


If you don't want to shrink the upper profile down at all, then that shape is just not going to be possible to fillet in MoI (at least not for some time to come anyway). You could try some other NURBS programs that have more advanced filleting than MoI such as SolidWorks, or you could also try switching to a more "low level" surfacing approach where you work on constructing surfaces more individually rather than using the solid modeling tools. That would be like building in some of the fillet surfaces by doing things like sweeping them, rather than using the solid modeling tools. But that tends to take a lot more time.

- Michael