Hi Moe, I got your e-mail and I replied to it with a tuned up version that will now fillet.

The main problem was your spoke was meeting your outer rim with just a slight amount of mis-alignment between the 2, which created a pretty tiny micro-edge.

Micro edges like that will tend to make MoI's filleter upset.

By rotating the rim by a slight amount (snapping one rotation point on to the rim's "seam" edge and the other to the end of one of the spoke surface), it then eliminates that micro edge when trimming those pieces to each other and then with that clean edge structure the fillet will succeed, I sent more details and an attachment for that through e-mail.

It's ok to have complex parts, but there still needs to be a pretty clean edge structure where all the parts connect to each other. If you have little tiny micro edges or little slivers of surfaces left over from booleans between pieces that were not quite aligned, that kind of a thing will prevent filleting from happening.

- Michael