Hi rayman - can you please post a .3dm model file of your object so I can test with it over here?

You can also send it to me at moi@moi3d.com if you do not want to post it here.

It tends to be very difficult to try and debug a problem just given a picture, if you can send the actual model files that helps a lot.

The mirror holder part may be a bug in MoI that I can fix up, but the other problem where you are pointing the arrow to is an unfortunate problem built into SketchUp, which is that it will not allow any polygon smaller than 0.001 units in size.

Do you also happen to be using centimeters or millimeters as your unit system? That will also unfortunately increase the chance of running into that "small polygon" SketchUp problem since the 0.001 units is actually always measured in inches. If you use millimeters for your units then that means that any polygon less than 0.0254 millimeters will just be completely ignored by SketchUp, leaving those little holes.

I'm probably going to try to do a kind of "hole sealing" mechanism that will collapse any polygons in that size to try and partially help this issue, but that will tend to alter the shape in those areas a bit, so it will actually be better if you scale your objects up by 10 or 100 times, or use Meters units instead of centimeters or millimeters.

- Michael