Hi Yenmonger, are you set with a solution to this now?

I think that the problem here is that you've found a shape that confuses the automatic inside/outside detection mechanism.

I think it's probably trying to fire a ray though the narrow area near the end of the wedge type shape. Then it's probably getting points that are within tolerance of each other and that's causing difficulty in the analysis.

If you run into this behavior in the future, you can try running the opposite boolean command to see if that will work.


I'll keep this model and take a closer look in v3 to see if the automatic inside/outside detector can be tuned up, but it is a sensitive area used quite frequently so it's probably a bad idea to mess with it right at the end of v2.

- Michael

FYI when you look. When viewing the surface normals in my CAM package, the indicator usually appears at the surfaces "center" position. Though with the little angular surface at the top, it appears at it's lower edge. Seemed kindof odd???

Hi Burr, it looks like your CAM package is taking the center of the underlying surface as the spot for displaying the normal.

In MoI, select that face and do an Edit > Separate to break it off of the main object, and then use Edit > Show pts to turn on control points and you will see that underlying surface is a kind of slanted parallelogram, the visible part is half of the underlying surface and the centroid point of the underlying surface is in that spot that you indicate.

That surface probably started out as a longer piece and the current one you see is the result of some other trimming or booleans that cut it in half diagonally.

- Michael

Yes, Mr. Gibson, I'm good now. Thanks again.

The piece of this model started life as part of a VRML file. I used Rhino to convert it to a series of lines, then used Rhino's mesh to polysurface command, then saved that as a 3DM file and used MoI for cleanup and enhancements.

So, it was probably related to the Rhino polysurface command. Or was it polymesh? Can't remember.

Hi Yenmonger, yeah probably Rhino's MeshToNurb command created that triangle that is half of a parallelogram. But there is nothing wrong with that.

I'm going to see if I can narrow down where in the inside/outside detection mechanism that things are going wrong and send this to the company that makes the geometry library so that it might get improved for v3.

- Michael

Hi Yenmonger, just a note on this - I was able to track down the bug in the geometry library that was making the inside/outside detection mechanism get confused for this case and I think that the fix is simple enough that I will include it for the v2 final.

- Michael

Neat, thanks!