Creating this level of interaction is easily the most challenging aspect of CAVE animation. Building interaction for the CAVE means making objects intelligent and able to react to people. A simple example comes from The Thing Growing . At one point in the narrative the Thing becomes so angry with the user that it hides under one of the rocks in the vast plain that the action takes place on. This is the point when the other rocks come alive and start to stalk and herd the user.
Intelligence has to be programmed into the rocks.
They have to know where the user is. They have to avoid each other, and they have to sneak up on the user and try to trap him. Instead of movement based on keyframes, the rocks are given a set of rules on how to move until one grabs the user. When that happens, all the other rocks scatter and the user's ability to navigate is taken away. He is trapped with a rock slobbering on him.