3d pdf objects

apparently there a couple of ways to embed 3d objects in pdf files. viewers can pan, rotate, and zoom on a quite smooth 3d model *drool*. i haven't seen much on the really really new format, and it's only supported in new versions of acroread. but the older u3d format is out there and already seems to be near-abandonware. there's a spec def on sourceforge that is the only free implementation i've found so far, though this page has some links i should check out. (click fast, it's tripod!) maybe one of these days i'll write something to convert meshes to u3d so i can embed them in docs.