Hi Burr, well tolerances come into play mostly when various kinds of geometry is created.

Many operations cannot be calculated directly, they go through a kind of iterative refinement until the result is close enough to the desired accuracy, with the desired accuracy being the tolerance.

Various things like general surface/surface intersection, fillet surface creation, sweeping, etc... are all things that use that kind of refinement.

If you have set a tolerance that is too loose, then it means the the surfaces that you generated will kind of sag away by some significant amount away from where their ideal locations would be. That's something that happens at the time that the surface is created, it doesn't have a whole lot to do with just saving data that has already been created.

Various kinds of systems can also have an error tolerance value that is associated with edges, which kind of marks the distance of the maximum gap between the 3D edge and the surfaces that are associated with it. This kind of error value assigned to an edge is not really too crucial to be sent down by export processes because it can be calculated later.


- Michael