Houdini 19.5 Nodes Dynamics nodes

POP Steer Align dynamics node

Applies force to agents/particles to align them with neighbors.

Since 14.0

This is a crowd behavior node, but you can also use it on regular particles (see the Output attribute parameter). You can choose whether each agent is “aware” of all the agents within a certain radius, or only the agents in its field of view.



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.

Output Attribute

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

This 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 “Crowd steerforce”. This number is used by the crowd solver to normalize and scale multiple forces that apply to an agent.

Force Scale

Strength of the alignment force.

Use Field of View

When this is on, each agent only considers other agents it can “see” in front of it (within Field of view degrees around its forward direction) with the Search radius distance. When this is off, each agent considers all other agents within the Search radius, regardless of their relative position.

Field of View

When Use field of view is on, the angle of the field of view (in degrees) around the agent’s forward direction. The agent will only consider agents inside the field of view and the Search radius.

Search radius

Only consider other agents within this distance (in meters).

See also

Dynamics nodes