Oh, ask around and you'll find athletes you have discovered more than axis of rotation. Ask them after they are out of the cast, however! Poser does have a joint limits system, although it is often disabled by users. Perhaps more troublesome is that I, at least, can't figure out their weighting system; how to make a joint move preferentially along one axis first whilst dragging on end of a limb or invoking IK. And as someone who has drawn/plastic kit-built/modeled the occasional robot, it is quite clear that while legs are often depicted as being nothing but hinges, the poor thing can't walk a step unless you cheat the joints a little and allow play in other directions (particularly long-axis rotation!) From the looks of it, pakled, your robot is simple enough so building him in the Hierarchy Room method would be quite plausible. By the by, that screenshot with bones leads me to believe you are NOT rigging in Poser 4. Would this be Pro-pack, or are you using an even more recent version?