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11.3. Robotic Motion 267
problem: how does the rendering software animate the virtual
figure as it reaches out to grasp your hand and shake it?
Thesoftwarewillknowafewthingsaboutthetask. Thecharacterwill
be standing on the virtual floor, so the position of its feet will be well defined.
It also must grasp your hand at the point in virtual space where the motion
sensor thinks it is located. This leaves a lot of freedom for the software, but
there are other constraints which should be adhered to if realism is to be
maintained. For example, the virtual character’s arms cannot change length
or pass through the character’s body. The angle of the character’s joints, elbow
and shoulders must also conform to some limits; otherwise, it could look like