Hi Giovanni,

> doesn't produce the same polygons on the left and right
> side of a perfectly symmetrical model.

If it was actually 100% absolutely "perfectly" symmetrical with not even the slightest tiny difference, then it should behave like you were expecting.

But one of the general problems with computer processing in general is that it tends to be difficult to get "perfect" results, it is not uncommon for results to have very minor deviations, like in the area of 0.000001 units in size for example, particularly with operations such as fillet surface building which has to go through a rather long series of fancy calculations involving calculating offsets and intersections between surfaces...

In this case, those tiny differences happen to be just enough to produce an extra level of subdivision in some of those areas.

If you select that fillet surface and use Edit/Separate to break it out into a single surface, you can then use Edit/Show pts to turn on control points and if you look closely you can see that the control point arrangement of the fillet surface is not 100% perfectly symmetrical.

It is within a pretty tight tolerance value, but not "perfect", if that helps to explain things... That is basically the cause of this problem that you are reporting here.


I do have a couple of ideas that may help to improve this and remove the differences caused by these small deviations, I'll see if it is possible to tune up this area.

- Michael