From:  Michael Gibson
2503.2 In reply to 2503.1 
Hi Yannada, these are a variety of tolerance and precision issues, nothing really out of the ordinary for either one but they are some slightly different things.

When you go to an extreme zoom level, you can usually expect for the shaded mesh display to start to lose precision and you can kind of see the limits of floating point numbers. The mesh will kind of "snap" to a smaller number of locations.

That's something that is a graphics card issue but it is common to all graphics cards and not just your particular model - it is because graphics cards use "single precision" floating point numbers for their mathematics, which have some limited precision but are also faster and use less memory.

Note that you have zoomed in by an extreme amount, so that the distance shown here is really very small:

You can generally expect that operations in MoI that involve fitting will get a result accurate to within 0.001 units, which is pretty much the same (or more accurate) as what is commonly done with most CAD systems.

It's normal for there to be gaps or overshoots on edges, as long as they are all under that tolerance level.

In the case that you show there, 0.000002 is clearly at a higher level of accuracy than 0.001 so no real problem at all there...

This process is done by all software that performs intersections on NURBS surfaces. Otherwise to get higher accuracy than that would cause the curves to become so dense with control points that the data size for models would go up by like a factor of 10 or 100, making models unwieldy and requiring too long to do the calculations.

So anyway that is something that is totally normal, other CAD systems will also generate the same kinds of tolerance levels and will expect to be able to handle things of that level of accuracy.

If you get things that look like misalignments that are of a much larger size than that, like larger than 0.001 units, then those would be more of something to worry about.

- Michael