"First because it's quite expensive and licensing it puts various restrictions on how you can price and deliver the product using it. In general it's very corporate/"Big Enterprise" oriented."

That's the impression that I get from this as well.

"Maybe at some point I will re-evaluate it but not anytime soon. Certainly not for the next version. It's more likely that I would do some experimental work on face transforms myself first before doing that."

I hope that you succeed doing so, that would be a very valuable addition to MoI3d imo.

Here's an example of what I have mentioned previously when testing Plasticity and the face rotation function.

With a simple test cube, I've rotated one of the face, and then performed a Chamfer operation (not fillet actually, I could not reproduce it using fillet, but I'm certain that I have seen some strange results with the fillet operation as well). You can see the unexpected result in the fourth image. The last image is the same Chamfer operation performed on one of the cube faces, without any rotation. Hope this helps.

Thank you.