ABSTRACT
Dynamic Turn Tightening Handling turning independently of locomotion is advantageous because it allows animators to avoid generating a large number of turn animations. Turning can be handled by using a target point, such as the next point along a navigation route or a point that is dynamically generated as seen in Figure 21.2. A turn angle is generated by taking the dot product between the alien soldier ant’s heading and the target and using that to solve for the angle. This value is then used to twist the spine of the solider ant, and that’s where our PID controller can assist us. Typically, a uniform twist would be applied to all bones in the spine, e.g., the alien ant soldier has four bones and our turn angle is 40 degrees. We would apply 10 degrees of twist to each bone. However, depending on the urgency of the situation, we can increase the proportional gain of the controller to tighten the turn (of course, within reason!) by twisting bones in different amounts.
