Adding and Removing Actors

Adding Actors to the Crowd

You can add more actors to a crowd simulation at any time. There is no particular limit to the number of actors that you can add to the simulation - see Loading Actors for the Crowd Simulation for more information.

To add an actor to the current crowd:

1. Set up one or more models that meet the CrowdFX requirements as described in Preparing a Model for CrowdFX.
2. If you have multiple crowd simulations in the scene, make sure that the Crowd model you want to use is current - see Setting the Current Crowd.
3. Open the CrowdFX Actors Proxies Property Editor either from the explorer or by choosing the CrowdFX Actors Edit Inspect Actor Proxies command from the ICE toolbar.
4. Do either of the following:
   • Click the Edit Get button and select a model or envelope mesh that's in the scene. If you pick a model, you will be prompted to select the body envelope mesh to use if there are other meshes in this model.
   • Click the Edit Import button and select a model (.emdl file) from the browser that appears.

   The new actor model is added to the Actor Proxies list in the property page.

   

5. In the CrowdFX Actor Proxy Property Editor that opens for the new actor, select and load its action sources as described in Loading Action Sources.

In the current Crowd model, an actor proxy model is added under the Actors_Proxies node and to the Actors_Copies group - see Anatomy of a Crowd Simulation.

The new actor is assigned the next available number for its Actor ID, and the crowd simulation is recalculated to consider this new actor. The Initialize compound in the Emit ICE tree for the simulation point cloud uses the Actor ID data to determine which actor mesh is instanced for each particle - see below.

Randomizing the Actors Instanced in the Crowd Simulation

By default, the Actor ID is randomized so that each particle emitted doesn't instance the same actor mesh. This is done using a Randomize Actor ID node plugged into the Actor ID port of this compound.

You can change the Seed value in this node to change how the randomization occurs, or use some other logic to assign Actor IDs, such as based on emitter ID.

To have all instances use the same actor, simply unplug the Randomize Actor ID node from the port. Then set the Actor ID value in the Initialize compound to the one you want to use. For example, you can keep multiple actors in your crowd, but just test one at a time.

Removing Actors from the Crowd

You can easily remove an actor from a crowd simulation. When you do this, the actor proxy model is removed from the Crowd model, but the original source model is not deleted from the scene.

To remove an actor:

1. Open the CrowdFX Actors Proxies Property Editor either from the explorer or by choosing the CrowdFX Actors Edit Inspect Actor Proxies command from the ICE toolbar.
2. Select the actor you want to remove from the Actors Proxies list.
3. Click the Edit Remove button below the list.

In its appropriate Crowd model, the actor proxy's Actors_Proxies node is removed, and the actor is removed from the Actors_Copies group.

The crowd simulation is recalculated to reflect the actor's removal: the actor's Actor ID is not used anymore so the distribution of instanced geometry is done with the remaining actors, but the same number of particles are still emitted.