An important part of crowd behavior is avoidance of obstacles. Think of an obstacle as anything that impedes a crowd member's progress. Examples of obstacles include walls, telephone poles, and fences, as well as other crowd members. Encountering such objects can cause avoidance behavior, which consists of any combination of slowing down, turning, and stopping.
There are several ways to implement avoidance in character studio, including:
Use the Avoid behavior primarily to cause crowd members to avoid other crowd members. It works by creating a spherical volume of avoidance around the avoided object, so it doesn't accommodate irregular objects.
The Avoid behavior is unlike any other behavior in Crowd. After all the other behaviors exert their forces on the delegates, Avoid takes over and has the power to turn, slow down, and even stop a delegate in order to make it avoid an obstacle.
Use the Wall Repel behavior to cause crowd members to avoid broad, flat objects such as walls and fences. You can set a maximum distance for the repel effect, and describe the rate at which the force away from the wall increases as a delegate approaches the wall.
Unlike the Avoid behavior, which can stop or slow down a delegate, Wall Repel simply exerts a force on the delegate to turn it away from the wall. It does not guarantee wall avoidance. You must work with it's distance and falloff parameters, as well as its weight in the Assignments and Teams dialog, to control its strength.
Use the Repel behavior to cause crowd members to turn away from an object. It works exactly like Wall Repel except that it uses a spherical volume rather than a plane. You can set a maximum distance for the repel effect, and describe the rate at which the repel force increases as the delegate approaches the obstacle.
Repel exerts a force on the delegate to turn it away from the obstacle. It does not guarantee avoidance. You must work with its Distance and Falloff parameters, as well as its weight in the Behavior Assignments and Teams dialog, to control its strength. Repel can be used instead of the Avoid behavior as a simple avoidance technique for non-terrestrial creatures such as fish or birds.
Use a vector field. A vector field is a special type of space warp that crowd members can use to move around irregular objects such as a curved, concave surface. You can use a vector field in conjunction with the Avoid behavior to make delegates slow down when they approach a complex object, and then go around it. This guarantees that the delegate will not pass through the obstacle's surface.
You can also use a vector field in conjunction with the Space Warp behavior. This simply exerts a force on the delegate that mimics the contours of the object. It does not assure that the delegate will not pass through the surface of the obstacle. You can use a vector field with both the Space Warp and Avoid behaviors to combine their effects.