Graphics Reference
In-Depth Information
seeing how objects are colliding with each other and also to make sure that Compound objects are set up cor-
rectly.
Joints, Ragdolls, and Robots
In 3D, as in the real world, joints are mechanisms that hold two solid objects together, allow certain freedoms
inhowtheobjectsmoveinrelationtoeachother,andrestrictotherkindsofmovements.In3Dthereareusually
considered to be three fundamental types of joints that differ in the kinds of movement they allow. These are
hinges, ball-and-socket joints, and slider joints.
Figure 8-48
illustrates the different ways that these joints behave. The hinge allows the objects to rotate on a
specific axis around a common point with respect to each other. The ball-and-socket joint allows combinations
of rotation around all three axes. The slider joint allows the objects not to rotate but to translate (move) along
an axis with respect to each other.
