Hi Danny,

> 1. How would 0.0001 tolerance effect the performance of MoI?

Well, there would be some negative side effects like some calculations taking longer but it shouldn't be too horrible. Things can get to be quite a bit worse when it's a few more orders of magnitude beyond that.

The problem with it being able to get set to just any value at all is that it is not uncommon for someone to just think something like "hey, to be on the safe side I'll set the accuracy to 0.000000001 so that there's no doubt that it will be accurate enough." But then as a consequence anything that produces a result by iterative refinement will take a lot longer to finish and will produce extremely dense curves. And once you get every intersection curve being made up of something like 100,000 control points, it will create much, much larger files.

But having a way to kick it up just one more notch from the default would help keep it from getting too crazy.


> 2. When the file does transfer to others with MoI, or transferred
> out to the other CAD formats, will that model retain the 0.0001
> accuracy and does that mean that anyone else will continue
> modelling at the default 0.001 or whatever is set on other
> CAD packages?

Well, the accuracy level is only something that comes into play when geometry is being created or intersected or things like that. So it's kind of baked into the model data itself in a certain sense. That's why it has a big effect on model size - when you have set a really high accuracy level it means that the geometry that gets spit out from things like surface/surface intersections (during boolean calculations for example) has a lot more control points in it because there it continued to refine things until it hit a higher threshold of accuracy.

The tolerance that is used for any further operations in some other CAD system will depend on how their tolerance system works.


> 3. Now I'm thinking, is a factor of 10 too much, maybe a factor
> of 5 making it a tolerance of 0.0002 would be ample, would there
> be a difference between the two?

There's not really a huge difference just in a factor of 2 like between 0.0002 and 0.0001 .

- Michael