Houdini 20.0 Nodes Dynamics nodes

POP Steer Avoid 2.0 dynamics node

Applies anticipatory avoidance force to agents/particles to avoid potential future collisions with other agents/particles.

Since 14.5

This is a crowd behavior node, but you can also use it on regular particles (see the Output Attribute parameter).

The collisionignore and collisiongroup point string attributes can be used to filter the avoidance behavior between agents. If an agent’s collisionignore string pattern matches the collisiongroup point attribute of a neighbor, the agent will not attempt to avoid the neighbor. Since the collisionignore attribute can have a different value for each point, the neighbor could still be configured to avoid the agent.



When this is off, the node will have no effect. You can animate this to turn the behavior on or off at different times.


Only modify a certain group or groups out of all agents/particles. You can name groups of agents using the Group Name parameter on the Crowd Source geometry node.


If turned on, shows the guide geometry for this node.


Even if the guide geometry is turned on here, it can be turned off by using the Hidden flag on the DOP node.

Output Attribute

If you are working with agents, set this parameter to Crowds steerforce. If you are working with particles, set this parameter to POP force.

Controls whether the node modifies the agent’s steerforce attribute (used by the crowd solver) or the particle’s force attribute (used by the POP solver).


Available when Output Attribute is set to Crowd steerforce. This number is used by the crowd solver to normalize and scale multiple forces that apply to an agent.

Particle Scale Multiplier

The node uses pscale as the size of each agent/particle when calculating potential collisions. You can use this parameter to scale the value of pscale in the calculation, allowing agents/particles to be more or less tightly packed. This parameter can be overridden by a pscalemultiplier point attribute.

Force Scale

Scaling factor for the strength of the avoidance force.

Anticipation Time

How far into the future an agent will look for possible collisions (this uses the current velocity to project the possible distance). The maximum distance that an agent considers another agent as a neighbor is the minimum of:

  • Agent’s current speed multiplied by the Anticipation Time

  • Neighbor Distance

Neighbor Group

Specifies the agents/particles that should be considered when searching for nearby agents.

Neighbor Distance

Maximum distance an agent searches for nearby agents.

Max Neighbors

Maximum number of nearest agent neighbors to consider when computing the agent avoidance force.

See also

Dynamics nodes