Hi Nick, well all NURBS modeling programs have a fitting tolerance that is used for operations that are calculated by a type of refining process, that's not something that's unique to MoI.

MoI generally targets an accuracy of 0.001 units, although I am working on converting to a more adaptable system that will use a fitting accuracy that is some fraction of the object's size which will help to make things work better on little sized objects.

But if you're looking for a system that does not use any kind of a fitting tolerance like that, you'll basically have to rule out every CAD system that's currently in use, since that's just a normal part of how a CAD system operates...

Some CAD systems allow you to specifically set the tolerance to a particular value - unfortunately that often times has a lot of negative side effects, including actually it getting set too loose and making things too inaccurate instead.

But yes, if you have some special need to have manual control over the fitting tolerance you may need to use some kind of special purpose CAD software that has all kinds of intricate settings like that which you may need to attend special training to figure out how to use, lest you set them incorrectly and actually mess things up...

Probably in the future at some point I'll add in a setting that will make MoI target a tolerance of 0.0001 units optionally instead.

Do you have some kind of manufacturing process where you would find a tolerance of 0.0001 units to be inadequate?

One thing to keep in mind is that it is not at all true that more tolerance is automatically better - a tighter fitting tolerance causes iterative algorithms to refine their results more and more, basically causing longer calculation times and also a much larger file size because things like intersection curves will have a zillion control points in them. So just setting the tolerance to some extremely small value is not really a good thing to do, that's something that I've seen as a pretty frequent problem in systems that allow people to set the fitting tolerance to any value at all.

- Michael