Hi Bill,

> Is the use of "JOIN" qualitatively different than using boolean joining techniques?

No, they both generate the same kind of result - a solid in MoI (and 99% of other CAD programs) is defined by a set of surfaces joined together at their edges to form a "watertight" skin. It should not matter which particular route you go through to get to that result.

> Is there a script or some other way to test joins to make sure they are good?

Yes, the first thing to look for is when you select an object look at the object type indicator in the properties panel in the upper-right area of the main window. That will read as "solid" if the object is a fully closed solid, and it will say "Joined srf" instead if it is made up of multiple surfaces joined together but with some open edges in it that are not joined to other things.

If you have an open object you can then set up a shortcut key that will highlight the "naked" edges (edges that belong to only one surface instead of being joined between 2 surfaces) so you can identify them. See here for how to do that:

http://moi3d.com/forum/index.php?webtag=MOI&msg=4869.5


> I know the script for identifying open curves, but this is different, is it not?

It's similar but yes a slightly different process - for surfaces/solids you're looking for unattached edges rather than just looking at endpoints.

- Michael