hi Rolf, > When I simply displace the position pdata, there are gaps between the > polygons. this depends on how your object is structured. if the faces are sharing vertices, this won't happen. if each face has distinct vertices there will be gaps as you move them. if you try this with "mushroom.obj" it works.
the other trick is to use (poly-convert-to-indexed), which removes the duplicate vertices from the object. because of this, it might also affect normals and shading. for some reason, it does not work with bot.obj, maybe its vertex positions are not perfectly aligned. but you can try it with built-in primitives like (build-cube). best, gabor
