GREAT DISCUSSION :) I agree with Phantast: "...solution ... optional rotational parameters: e.g. a dial for "rotate local X" and another for "rotate global x"." For a single pose (picture) it doesn't matter what the math is internally - just have the program calculate whatever numbers it needs to reach the requested position. In this case, it is purely a matter of creating a user interface that gives the user the control they desire. For an animation - quaternions versus Euler angles - it isn't like Poser provides any way to control what path it takes - it always takes the path determined by its ordering of the 3 angles. This is no better than the quaternion solution - it just fails in different situations. In either math approach, what is needed, as was mentioned, is some way for user to SPECIFY what path is desired. (With either approach, the bad cases can be improved by adding more key frames.) I don't have enough experience to prove it, but it should be possible with quaternions to get any desired path by specifying the direction to be moving in at each key point, similar to defining a spline path through space. That is, quaternions deal with ROTATION change in a way that allows well-developed solutions for POSITION change to be used. Euler angles do not have such desireable properties. What I'm saying is that quaternion-based applications will eventually offer superior user-interfaces for animation. (Maybe they do now - I can't afford any of the high-end stuff...) - - - - - - - - - - The Direct Manipulation tool in Poser5 looks like it does useful math - turn one of its rings, and see how Twist, Side-by-Side, and Bend change for a given body part. Personally, I have trouble with the DM tool. I end up clicking on a body part when I don't want to - especially when trying to do a freehand movement. I also have trouble doing the freehand movement I want - it doesn't seem to act like a trackball - I often get a rotation in the plane of the screen (like hands of a clock), when I am trying to pull a figure head-over-heels. The end result is that I never bother using the DM tool. A shame, as it is such a promising idea... - - - - - For many uses, I find dials easier for precise results. So while we're wishing, I wish there was a "3 dials" version of the DM tool. Or at least, a DM tool that disables part selection. For example, hold down ctrl if want to pick new part, otherwise, stays with current part.