Hi Micha - the big kink at 16 degrees happens because of the curvature of the fillet surface is quite shallow in the longer direction, which I highlight here:




Since the surface is only gently curved in that direction, an angle of 16 degrees does not cause the fillet surface itself to become subdivided.

As I've mentioned before, if you have a situation where a surface does not get subdivided but its boundary edges do, it can lead to these kinds of kinks.

There isn't really any bug here - to solve the big kink you need to do something to cause additional subdivisions of the surface.

The typical method for that is to decrease the angle parameter until it is less than the angle of that shallow curvature for that long direction on the fillet - that will solve the problem. For example try using an angle of 12 instead and your kink problem will be greatly reduced. As you go to a tighter angle yet it will continue to be reduced.

Another way you can solve it is to use the "Divide larger than" setting to force that shallow long fillet piece to get subdivided. For example with Angle 16, try entering a value of 20 for "Divide larger than", and it will force any polygons longer than 20 units in size to become additionally subdivided - that will force additional subdivisions of the surface and again solve the problem.

When you see this problem, it is caused by a surface getting a coarse mesh on it, and the solution is always going to be to force additional subdivisions...

I think that a "Chord height" tolerance value which I am also planning on adding would be a pretty good parameter to help in these situations as well.

But basically if you want to improve the tessellation here, you need to manipulate the settings to produce the result you want - normally the solution is to just make a tighter angle but if you want to avoid that you will need to use some of the other settings instead of angle alone on shallowly curved things.

Keep in mind that 16 degrees is a rather coarse angle, the default that MoI uses for angle is 12, which is already somewhat coarse to start with.

- Michael