If anyone is interested I had to pull out Foley van dam Feiner and Hughes and discover how to cast a ray into the screen from a mouse point and then use it to calculate if and where it interesects any particular objects face. You can of course use the OPENGL selection method (limited to 64 named Items) but it really is pants.

The method I implemented does the following:

1 - calculate ray and ray normal

2 - do quick sphere based interesetion test

on modelled parts COG’s

3- do a face by face analysis to determine

if the ray hits the plane of an individual triangle.

4- tranform all all face coords and hit pt into the same coordinate system, and then rotate to eliminate an axis.

5- perform a simple 2d PtInPolygon analysis

as all points can be represented in 2D integer space.

So if anyone is interested let me know and I will put hte psuedo code out there.

P.S. If you dont know what foley van dam feiner and hughes is dont worry, I have owned the book for 4 years now and I’m still not quite sure.