You can select one or more surface objects (polygon mesh or NURBS surface) to be used as the terrain upon which the actors will move or stand in a crowd simulation.
When you add a terrain object, raycasting is performed from each particle (actor) to detect the terrain's surface, and each particle's position is updated to match it.
The actor's skeleton is adjusted to accommodate the terrain, keeping the actor's feet on the ground. However, if the actor's legs are going through the terrain (such as for bumpy terrain or a steep hill), you can add a constraint to remedy this problem - see Constraining the Legs to the Ground.
To add terrain objects to the current crowd simulation, do any of the following:
Crowd Create Terrain command from the ICE toolbar.
Crowd Create Terrain command and pick a single surface object.
The simulation point cloud's Particle Simulation ICE tree is updated to include a Stick to Ground node inside the Simulate Collision Avoidance compound. This node finds the terrain by raycasting, then updates the particle's position accordingly.
The terrain objects are referenced in the Terrain group in the Crowd model.
If you duplicate a terrain object, its copy is automatically references in the Terrain group.
