Thursday, July 3, 2008

Rig design process Part 6 Arc



The difference between the IK and FK


In real life, organic creatures always move in arcs or a sort of figure “8”. Our hands move naturally in arcs when we gesture or when we are just swinging them at our sides. Our hips move up and down in arcs as we walk. When you rotate a joint in a 3d program, it will actually naturally move through an arc, just as that joint would move in real life. Sometimes we don't want the lower nodes in a hierarchy to move with the upper nodes. You could manually go frame by frame and animate the joints keep in the some position but that is extremely tedious. Instead, you can set up an Inverse Kinematics chain that will lock joint and figure out the calculations you. However, there will also be no arc to the motion of an IK control, it moves linearly between poses. Where you naturally have an arc in the FK control, you will have to add arcs manually in the one with IK.

1 comment:

Dylan said...
This comment has been removed by a blog administrator.