Thanks Michael,
Some good explanations here.

The model started out in Rhino. The template I used was small objects meters: Units: Meters Absolute tolerance: .001 m.
What would be the best unit and tolerance setting in Rhino for bringing stuff into MoI?
Bill

Hi Bill,

> What would be the best unit and tolerance setting in Rhino for bringing stuff into MoI?

It depends on the size of the object that you're building - but if your object is going to be less than 1 meter in size it's probably best to use centimeter units for it instead of meters.

- Michael

Hi Michael,
Most of the stuff I build is the size of a building, but usually there are a lot of associated small elements like the one that started this thread.
Thanks for your help.
Bill