   3d modeling (blender-style) mouse rotation (not arcball?)
  I'm wondering if someone can enlighten me on some terminology, I'm interested in creating a mesh viewer that I can rotate around with the mouse. I'd like to duplicate the kind of mouse-based rotation you find in modeling software like blender, but I don't know how to define it enough to search for it.I hear about arcball rotation a lot around here, and I've taken a look at some implementations of it, but it just doesn't seem right to me. From my understanding of arcball ("grab a point on a sphere, and rotate it"), you can't ever rotate a model more than 180 degrees in a single press-move-release sequence, and the deltaRadians/deltaPixels changes as you get closer to the edge of the "ball". Plus in the two demo implementations I've played with you get a ugly behavior discontinuity once the mouse passes outside of the imaginary "ball". Were these just poor implementations, or is this inherent to arcball rotation?When I play with blender it feels so much more natural. If I start on the left side of the screen with blender and drag to the right side, I can rotate my model probably something like 400-500 degrees (more than a full rotation), and the speed of rotation is always constant with the speed of the mouse. Is this still considered 'arcball' (maybe with a modification), or something else entirely?Sorry if this gets asked a lot, but I'm just not sure what terminology I need to search for.Thanks!   
  Sounds like the difference between Inverse Kinematics and Forward Kinematics, except with only a single joint.IK: "I want the point on the object grabbed by the mouse to always get as close to the mouse as possible."FK: "I want to adjust the angle, and watch what the object does as a result."   ;  Sorry, I don't know how blender does it, but if it's like 3ds Max, then it's a simple first person camera stuff.But it can be arcball, just multiply the rotation angle with a constant, bigger-then-one value (or divide the mouse delta, doesn't matter).But I don't think you are quite right about the arcball's working: it's not like (AFAIK) you are grabbing a point on the surface of the virtual ball, it's much simpler that that (if you look for "first person camera" here on the forums, you will find details of both kinds of rotations, or even of the "grab a point on the ball" rotation).But these are 3 different kinds of rotations.I may be wrong with the term "arcball", but you can find all 3 here   