Emit from Curve

 
 
 

This compound emits new particles from a curve.

Plug this compound's Emit output into the ICETree node. This compound should be plugged in to the first port of the ICETree node because you usually need to emit particles before any other node or compound can be evaluated.

For more information, see Emitting Particles from Curves [ICE Particle Simulations].

Tasks: Particles/Emitters

Output Ports: Emit

Enable

Turns the particle emission on and off.

Emission Parameters

Emitter1

Plug in the geometry from which you want to emit particles. This must be a curve geometry. You can plug multiple geometries into this emitter.

Select Rate Type

The way in which particles are emitted:

  • Total Number of Particles emits all particles set by the Rate parameter at once at the first frame of emission.

  • Number of Particles Per Second emits the number of particles set by the Rate parameter over time.

See ICE Particle Rate (Amount) [ICE Particle Simulations] for more information.

Rate

The number of particles that are emitted according to the Select Rate Type you selected.

Note that in some cases where particles are deleted immediately using one of the Filter compounds (such as Filter by Weight Map) in the Emission Control group, the actual number of particles that are displayed on screen may be less that this Rate value defines. That is because the Filter compounds delete certain particles immediately after they are born.

Seed

This number is used as the basis for the random generation of particles. If two different particle emitters use the same seed, you may get identical results in their emission. Change the seed value to get a different random generation of particles.

Emit Only at U Value

Emits particles only along the U direction of the curve.

U Value

Emits particles starting at this value along the curve. If you animate this value, you can create a fuse effect of particles being emitted as they run along the curve.

U Variance

Adds a variance to the particle emission along the U direction of the curve.

Initial Values

These parameters are the same as the Initial Value parameters in the Emit from Geometry compound.

Direction and Speed

Select Initial Direction Method

Select from three methods to control the direction of movement of new particles:

  • Use Emit Location Tangent uses the emitter curve's tangent to control the particle's initial direction.

  • Use Emit Location Tangent Negative uses the direction opposite to the emitter curve's tangent to control the particle's initial direction.

  • Use Initial Direction Vector uses the Initial Direction value that you set to define the particle's initial movement.

See ICE Particle Direction [ICE Particle Simulations] for more information.

Direction

If you selected Use Initial Direction Vector as the Select Initial Direction Method, you must set this value to control the initial direction of movement for all new particles. These values use global XYZ space. If you set all the axes values to 0, the particles are emitted but stay stuck to the emitter.

The particle's direction stays the same over its lifetime until some type of force changes it.

Randomize Direction Start Angle

Randomizes the direction of the particle as they're emitted within a range as defined by the start and end angles. These values are in degrees. A range of 0 - 360 degrees is a full rotation.

Randomize Direction End Angle

The end angle of the range in which particles are randomized.

Speed

Defines the speed at which new particles are moving when they are emitted, which is the number of Softimage units per second. If this value is set to 0, the particles are emitted, but simply remain on the emitting object. This parameter controls only the initial speed, but you can change it over time using a compound such as Modulate Velocity Over Time.

See ICE Particle Speed [ICE Particle Simulations] for more information.

Fast Moving Emitter

If the emitter that you are using as a surface to create new particles is moving very fast, then you may get "banding" effects. This is because particles are only emitted each frame. If the velocity of the emitter is high, then you may see clumps of particles appearing as the emitter moves through space. This toggle is used to correct this artifact and produce a smooth stream of emitted particles.

Execute on Emit1

You can plug in nodes that have Execute output ports. These ports only get executed once when a particle gets created.

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