Object Bind operator

The Object Bind operator can be used to bind particles to objects and their surfaces. Various settings allow you to control the strength of the binds across multiple particle data channels (position/rotation/scale), as well as various other surface constraints.


Bind Objects Rollout

Object Bind Type

  • Position: binds particle positions to objects.

  • Rotation: binds particle rotations to objects.

  • Scale: binds particle scales to objects.

Objects

  • Object list: the list of objects to which particles will be bound.

Bind Mode

  • Lock to object: particles will be bound to object transforms.

  • Lock to surface: particles will be bound to object surfaces.

  • Snap to surface: particles bound to surfaces will immediately snap to valid surface locations.

Sample

  • Sample type: controls which sampler will be used to determine closest-surface proximities for particles.

Uniqueness

  • Seed: the seed value for all varied parameters.

Bind Position Rollout

Sticky

Sticky bindings constrain particles to consistent distances from their target surface.

  • Friction %: controls the amount of resistance a particle will exert on forces that try to move it along its target surface.

  • Variation %: the per-particle percentage of variation to apply.
  • Inherit %: controls the amount of velocity particles will inherit from the motion of their target surface.

Velocity
  • Make parallel to closest point: particle velocities will be projected along the nearest point on the object to which they are bound.

When bind mode is set to “lock to object”, the closest point will be the object’s pivot. When bind mode is set to “lock to surface”, the closest point will be the closest point on the object’s surface.

  • Relative to face/vertex normals: controls which mesh element the projected velocities will be made perpendicular to.

  • Verlet integration: after all bind calculations are completed, the particle velocity will be set to the vector between the final particle position and the start particle position.

Enable verlet integration if you want particle velocities to reflect position changes caused by object bindings.

Linear Spring

Linear Spring bindings modify particle velocities such that they point directly at their target surface locations.

  • Force %: the force of the resulting velocity.

  • Variation %: the per-particle percentage of variation to apply.
  • Interpolate previous: controls whether particle velocities will be interpolated with their previous values, based on the force multiplier.

Dynamic Spring

Dynamic Spring bindings modify particle velocities such that target surface vectors are added to their current velocity vectors.

  • Stiffness %: the strength of the target surface vector.

  • Damping %: the amount of damping to apply to existing velocities, prior to the addition of the target surface vector.

  • Max force: the maximum magnitude of target surface vectors.

  • Variation %: the per-particle percentage of variation to apply.
Proximity influence

The proximity influence extends outwards from the bind object’s closest point.

  • Distance: particles within this distance will be fully affected.

  • Falloff: the effect on particles beyond the base distance, but within this falloff distance, will diminish according to the inverse-square law.


Limits
  • Limit offset: limits the distance between a particle’s bind target and the actual distance to the nearest point on the surface.

  • Min: the minimum allowable distance between a bind target and the nearest point on the surface.

  • Max: the maximum allowable distance between a bind target and the nearest point on the surface.

  • Variation %: the per-particle percentage of variation to apply.

Bind Rotation Rollout

  • Force %: the amount of force used to constrain particle rotations to their initial orientation offset from the surface.

  • Variation %: the per-particle percentage of variation to apply.
Proximity influence

The proximity influence extends outwards from the bind object’s closest point.

  • Distance: particles within this distance will be fully affected.

  • Falloff: the effect on particles beyond the base distance, but within this falloff distance, will diminish according to the inverse-square law.


Spin

  • Verlet integration: after all bind calculations are completed, the particle spin will be set to the difference between the final particle orientation and the start particle orientation.

Right Vector

  • Right vector type: the location relative to the surface or the world from which right vectors of the binding orientation matrix will be derived.

  • Up vector type: the location relative to the surface or the world from which up vectors of the binding orientation matrix will be derived.


Bind Scale Rollout

  • Force %: the amount of force used to constrain particle scales to their initial scale offset from the surface.

  • Variation %: the per-particle percentage of variation to apply.
Proximity influence

The proximity influence extends outwards from the bind object’s closest point.

  • Distance: particles within this distance will be fully affected.

  • Falloff: the effect on particles beyond the base distance, but within this falloff distance, will diminish according to the inverse-square law.