Perch On

PerchOn Behavior (bePerchOn) defines all surfaces on which a flock boid may land/stop. Its parameters define the condition to land/stop on a surface.
PerchOn behavior in the behavior editor

For more information on flock in Golaem Crowd, see Flock Locator

To use a PerchOn Behavior, a Flock Behavior and a Flock Locator are mandatory. 


  • Behavior Editor / Behavior Library: 
  • Golaem Menu: Crowd Behaviors / Behaviors / CrowdBePerchOn Node
  • MEL command: glmCrowdBePerchOnCmd;


A PerchOn Behavior defines the following specific attributes. For common attributes see Behavior Common Attributes.

Perching Attributes

Perching behavior detects when the boid trajectory crosses a given Maya Mesh. Perching will progressively align up of boid with the hit mesh normal, then wait for some time and take off in the mirror direction of landing, relatively to mesh normal.

In Perching Supports

The Maya meshes on which flocking Entities may land

Dynamic Perching Supports

If the support is moving, this parameter must be set to true to handle support movement.

Deformable Perching Supports

If the support is deformed based on time, this parameter must be set to true to handle deformation.

Landing Distance

The distance on which the boid will interpolate its orientation to land. It replaces starting speed which was harder to configure.

Landing Speed

If the boid must have a speed when landing, set it here

Stop Action

Depending on the setting, the entity orientation will be set to prepare for take off, or to stay on the support.

Take Off Distance

Same as landing distance, but for take off, i.e. when the behavior is stopped. It replaces stopping speed which was harder to configure.

Perching Raycast Distance

The distance from which raycasts are sent to detect perching supports from each boid. Should be greater than landing distance. When a boid has a valid raycast on the support, it will take the hitpoint as steering/seeking point until it is in "Landing Distance".