Hi Brian,

For #1 you mean the little black slivers in the top middle area?

What rendering program are you using? I gave a quick try in Cinema4D and couldn't see anything wrong:



My best guess would be that your program doesn't like N-gons, try switching Output: to Triangles only and see if that solves the problem.

If you still have problems, you may need to send me the polygon output file so I can take a closer look, you can attach that here or e-mail it to me at moi@moi3d.com

For #2 I'm not quite sure which edge you are talking about - do you mean the whole top of the mouse? Do you have the older version of the mouse that you could post so I could try that same fillet again?

For #3, I was able to put a fillet around the thumb depression up to 0.05 units, but no larger. I'm not quite sure what is going wrong on this one, chamfer actually works up to a larger distance.

Taking a closer look at the surfaces, I think it is related to the very shallow angle between these 2 pieces:



Turning on control points, this is the point where they are joined:



Extending the tangent directions off to one side, you can see the tangents do not align, there is about a 3.5 degree crease between these 2 surfaces, they aren't completely smooth with one another:



This kind of "pretty close to smooth but not quite" tends to create stress on the filleter because it causes it to try and intersect 2 nearly tangent fillet surfaces with one another. This happens to be a tough area of calculation for intersections and it can tend to go wrong.

I think that probably if this juncture was completely smooth the filleting would go better there.

- Michael