Hi Sharif,

> Is the fillet in this condition not possible in MOI?

It's not just a MoI problem - the curve fillet for that case is actually not physically possible at all...

The way curve filleting works, is it tries to put in an arc of your given radius that is tangent to both of the curves.

If the 2 curves are not in the same plane, there is typically not any such given arc that exists, it's too easy for the tangents to be going in different directions. In order for an arc to be possible the endpoints of the arc and end tangents of the arc must all be in one plane.

This may be confusing because you may think what about making a solid edge fillet something like this:





But even though this looks like a curve fillet above there, that edge is not actually an arc, it's kind of a slanted cross-section of the fillet surface.

If you turn on surface control points of the fillet surface you can kind of see how the fillet surface is larger than that piece and that the rounded corner is actually a kind of slanted slice out of a larger rounded corner surface:



So since it is not physically possible to make an arc fillet in that situation you probably want to do a blend technique like Steve shows - unlike curve filleting, blending does not require the end points and tangent directions to be all in a single plane.


Or depending on what you want in the end you may not want to try and make a curve fillet in the first place but instead wait to get an edge fillet later on as above.


- Michael