Hi Ed, usually most rendering programs offer some way to select different polygons out of a model and apply a different material to them. But I'm not familiar enough with Bryce myself to know where or if this is provided over there. You'll probably have to find a Bryce forum to ask about that.

But one thing you might try - I wrote a little program that you can download here: http://moi3d.com/download/SeparateOBJ.zip - if you run that program it will edit an OBJ file and it will break objects up into smaller objects along any sharp edges in the shape.

Then when you import that OBJ into Bryce, it will probably come in as separate objects and that may make it easier to assign different materials.

- Michael