Flock Locator

The Flock Locator defines the volume in which flocks can move thanks to the Flock and Steer behaviors.

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CREATION

A Flock Locator is automatically created when a Flock or a Steer behavior is added to the simulation.

• Golaem Shelf:  / right click / Flock Locator
• Golaem Menu: Environments / Flock Locator
• MEL command: glmFlockLocatorCmd;

Preliminary Notes

Golaem Crowd flock implementation is based on Craig Reynolds' Boids.

Each flock entity is a boid. Each boid has 3 basic rules in addition to optional steering behavior:

• Separation : avoid crowding with neighbors
• Alignment: try to align its velocity with neighbors
• Cohesion: try to stay near neighbors

For each of these rules, a specific neighborhood is considered. The neighborhood is defined by a radius around the current boid, and an angle with current boid direction. All boids outside of radius, or forming an angle with boid velocity wider than angle, are ignored. Additionnaly all boids inside 3*boid radius will be considered in neighborhood so the boid radius, defined when generating from Population Tool, has a strong impact on the final flock homogeneity : greater radius will lead to more separation, cohesion and alignment.

Known limitations

• The flock locator can only be a sphere (i.e. cannot use meshes as flock containers).
• Locator keyframed positions, size and scale will be ignored. Flock Locator radius and position are evaluated at start frame. 
• Goalem Crowd Flock does not provide an out of the box solution for controlling yaw/pitch/roll limitations on boids.

CONFIGURATION

Flock Attributes

Weights Attributes

Steering Flocking Ratio	Depending on the desired result, one can choose to emphasize on steering toward a target (flee/seek/wander), or on flocking effect. A ratio of 0 will negate flocking effect, and just steer toward the current target. A ratio of 1 will only apply flocking effect and won't steer at all. Beware than only applying flocking effect won't move a boid, if it has no other boids in its neighborhood (because no cohesion/separation/alignment can be determined in that case). A ratio of 0.8 is given by default : mostly flocking, while still keeping some steering influence.
Separation Weight	Weight of separation in boid final decision. When null, boids will crowd in some points, while great values make them split as much as possible
Alignment Weight	Weight of alignment in boid final decision. Try to align boids velocity with their neighbors
Cohesion Weight	Weight of cohesion in boid final decision. Try to make boids stay near neighbors

Boid Neighborhood Perception Attributes

Attributes of a flock locator

These are advanced flock parameters. They allow to define a custom shape and size for the neighborhood considered for each goal. Note that default values should be fine in most cases.

See Craig Reynolds' Boids page for detailed explanations and a neighborhood space figure. 

See EntityType and PopulationTool for more information on entity radius and scale parameter.

 

Inner radius Factor	Controls the radius in which all boids will be considered as neighbors, expressed as an entity radius factor. This neighborhood is used by all goals, in addition to each specific neighborhood definition.
Separation Radius Factor	Boid neighborhood radius factor for separation, expressed as an entity radius factor
Separation Angle	Boid neighborhood angle for separation
Alignment Radius Factor	Boid neighborhood radius factor for alignment, expressed as an entity radius factor
Alignment Angle	Boid neighborhood angle for alignment
Cohesion Radius Factor	Boid neighborhood radius factor for cohesion, expressed as an entity radius factor
Cohesion Angle	Boid neighborhood angle for cohesion

Obstacles Attributes

Maya Mesh flock avoidance