Autodesk 12812-051462-9011 User Guide 3 - Page 1836

to their scale dependency. Retargeting means to scale the animation so it matches the objects onto which you are mapping the motion. You need to retarget only when the size or proportions of the incoming model differ from the size or proportions of the current model. Retargeting applies to any kind of animation, from matching fight choreographies, to changing a weather balloon's fly-through trajectory over hills and valleys. The down side of this is that essentially you have to set up the scaling relationships by hand; the good news is that the steps are fairly straightforward, and that once you have retargeted, the settings are reusable for all animation mapped between the same two sets of objects. While retargeting is a general-purpose feature, it is especially useful for transferring animation from one character to another, when the characters are of different sizes, and possibly of different proportions (for example, a human model to a gorilla, or vice versa). You can transfer IK animation onto an FK rig, or vice versa. There are some rules of thumb when you work with mapping character animation: ■ In a walk cycle, the root of a character moves, and all other movement is typically rotation. Because of this, usually you want to map the root motion and the rotation tracks, and leave the others alone. The exception to this is when arms or other parts (tentacles?) are animated by IK. When IK is present, you need to take the additional step of mapping and retargeting the IK goals. ■ The legs need to reach the "ground," and feet should not slide. Because of this, use the legs as the basis of recalculating the scale for the target character. ■ Characters are usually symmetrical. Because of this, usually retargeting one limb does the trick for both. If a character's limbs are not symmetrical, retarget each of them individually. If the current model uses forward kinematics, then use the FK Retargeting Extent controls as well. Procedures To retarget one character onto another: This procedure is not a detailed procedure, but an overall workflow. It assumes you have already saved the incoming character's animation, then loaded it onto the current character, as described in To use the Save Animation and Load Animation commands on page ?. Saving and Loading Animation | 7091