I have imported the .obj output from Knotplot into Wings for further tweaking. Sometimes I just assign different material groups for further texture adventures in Bryce, or i like to select the whole object, do an INSET command, Then an inward EXTRUDE AREA, Then I assign the remaining selected faces with "Hole" material. Those faces won't be exported when you save it as an obj to import into Bryce. When you render it with a material of your choosing you'll see that its been "skeletonized". Sometime this looks even better if you subdivide(Smooth) once before export. Cheers, Dan