Create panel > Helpers > Object Type rollout > Crowd > Collisions rollout
Select a Crowd object. > Modify panel > Collisions rollout
During a crowd simulation, you can use this rollout to keep track of collisions defined by Avoid behaviors. A delegate whose hard radius as defined by the Avoid behavior intersects with the hard radius of anything it is avoiding is marked as having collided at that frame. If too many collisions occur, the simulation might not provide satisfactory results; in such cases, you might want to alter the simulation setup.
Hilite Colliding Delegates—When on, delegates that collide are highlighted in the collision color.
Only during collisions—Colliding delegates are highlighted only in frames in which they actually collide.
Always—Colliding delegates are highlighted in frames in which they collide and all subsequent frames.
Collision Color—The color swatch indicates the color used to highlight colliding delegates. To change the color, click the swatch and use the Color Selector dialog to set a new color.
Clear Collisions—Clears collision information from all delegates.
If you re-solve part of the simulation, new collision information for the recomputed frames will be computed. However, if you move a delegate manually, its collision information will remain the same, and may be incorrect. In such cases, use Clear Collisions to correct the collision information.