Hi nos - well it seems to be working in the sense that it is generating a rounded fillet surface between the 2 surfaces.

What result were you hoping to get as far as the ends being trimmed?

It would probably work better to get a trimmed down fillet result if you were filleting a solid where there were side walls that the fillet could get intersected with.

Without the side walls in place, for this case here you will need to trim the fillet yourself to whatever you want to have as its side shapes.

I've attached one version that has it trimmed - here I just took the edges of your surfaces and flattened them into a 2D curve and used it as the cutting object in the Trim command to slice off the ends of the fillet.

But note that makes for a slightly pointed corner in where the fillet is cut up, so I'm not really sure if it's what you want.


Usually with this kind of a thing it's better defined to have a solid because then there is a full side wall that can be used to intersect the fillet with, without any actual side wall geometry the shape of how the fillet should be trimmed is ambiguous.

- Michael