Populate Agents

Once you have set up your Material and Character variables and have agents in your scene, you can “Populate” your agents. This process will distribute your models and select characters, materials and properties for your agents.

You can populate agents in two ways:

  • Automatic selection using the Populate in the Node Editor.
  • Manual selection via Properties ‣ Object tab ‣ CrowdSim Materials/CrowdSim Character.

Automatic selection

Assign variables to your agents

Once you have created your mesh variables you can apply these variables onto your models. This is done using the Node Editor.

  • Go to the Node Editor.

  • Add a new CrowdSim node tree or use an existing one.

  • Add a Populate node to the node tree. Select the model you want to apply to the agents.

  • Connect a Mesh Variable, Material Variable or Agent Variable node to the Variances socket of the populate node.

  • When connected the nodes displays the Material Variables and Mesh variables of the model in the node.

    In the Mesh Variable node you can select the weights for the characters and the weighted mesh groups the model has.

    In the Material Variable you can enable material variables to be populated and the range.

  • After pressing Populate of the Populate node all agents in the scene will get random mesh/material variables.

    You can use the Object Selector node and connect it to the Agents socket of the populate node to limit the affected agents.


  • After Automatic selection you can still change the model, character, meshes and materials per agent. See Manual selection for more information.

  • Agents that are locked will not get new values for characters and meshes. They will keep the values they already have.


Manual selection

When using manual selection you can only modify a single agent at a time.

Changing the model of an agent

You can change the model of the selected agent in the Properties ‣ Object tab ‣ CrowdSim panel.


Change the Base Model to change the model of the agent.

Changing the mesh variable of an agent

You can change the character and meshes of an agent in the Properties ‣ Object tab ‣ CrowdSim Character panel.


Changing the material variable of an agent

You can change the materials of an agent in the Properties ‣ Object tab ‣ CrowdSim Material panel.




  • Keep the range of material variables small. For every combination of material variations a copy of the material is created. When you have a lot of options or a large range it will influence the render performance.

    In Blender a material is part of the mesh data so even complete meshes are copied.

  • When linking a model from another blend file, make sure you link in the Images you want to variate. Otherwise these cannot be found. Most of the time it is enough to load the Character Configuration (Node tree with the character node) and the images.


This section describes the nodes that can be used for populating your agents. These nodes can be found in the Populate category in the node editor.



With this node you can select the models for your crowd simulation. You can create several variances of this model by attaching Material and Mesh Variables to this node. You can also configure the agent(s) properties with the Agent Variable node.

Agent Variable


With this option you can variate speed and acceleration and other properties of your character.

Options to variate:

  • Initial Speed: Initial speed of the agent
  • Normal Speed: Speed considered the normal speed of the agent
  • Maximum Speed: The maximum speed of the agent
  • Acceleration: The Acceleration of the agent
  • Mass: The mass of the agent. Intersection uses this to calculate the impact of the collision.
  • Radius: The radius of the agent.
  • Height: The height of the agent.
  • Animation Offset: The animation offset of the agent.

Material Variable


Configure which material variables and their values should be used. The options displayed are from the character connected to the Populate node.

Mesh Variable


Configure your armature and meshes. The options displayed are from the character connected to the Populate node.