Hi Lewis, no problem. And yes, filleting in MoI does tend to be pretty sensitive to curves which come pretty close to being smooth to one another but are just something like 3 or 4 degrees apart from being actually tangent to one another. That's the kind of situation where you'll get separate segments in what you'd rather have as a smooth piece, if they are more exactly smooth to one another they should get fused into a longer single segment instead of separated.

Filleting does not like that kind of "close to smooth but not quite smooth", because fillet surfaces only naturally meet up with each other at totally smooth areas - at any kind of sharp point it means the fillets themselves do not touch each other and a juncture patch has to be created. But in a very shallow corner the juncture can be some kind of tiny slivery piece and often times little slivery pieces cause difficulties for intersecting and joining things together.

So it would probably be better in that particular case for MoI to modify the shapes of the "almost smooth" pieces so that they would instead be totally smooth to one another and then could be combined. That can sometimes cause other problems though, because it changes the shape of the curve and if the shape changes too much that can be undesirable as well. It's somewhat difficult for an automatic mechanism to judge very well for how much of a change should be allowed.

Right now you have to use your own judgment to clean up such things in order to improve the quality of the geometry.

- Michael