The Generate Strand Trails compound creates strands similar to the Create Strands compound, but instead it dynamically creates as many strand segments as you need for a simulation based on the number of frames in the simulation and the limit of segments you have set. One strand segment is created per second up to the maximum number of segments that you have set. Only when the maximum number of segments is reached do the strands “release” from the emitter and move away from it.
When the strands do release from the emitter, their length is affected by the particle’s velocity. This means that a fast moving particle will have longer strands than slower moving particles. The strands “stretch” to accommodate the faster velocity.
When the particles are emitted, the strands follow behind, creating the effect that the strands are growing. This compound is useful for simulating elements such as tree branches, root systems, branched lightning, or grass sprouts where the particle strands grow but never leave the emitter.
With the Generate Strand Trails compound, you can use these Strand compounds: Twist Strand, Bend Strand, Turbulize Strand, and Strand Sine Wave Movement.
If you use the Generate Strand Trails compound, do not also use the Create Strands compound in the same ICE tree.
To generate particle strand trails
1. Create a particle emission—see Creating ICE Particle Emissions for information.
2. In the ICE tree’s preset manager, click the Task tab and select Particles.
3. Drag the Generate Strand Trails compound from the Strands group into the ICE view.
4. Plug this compound’s Execute output into an Execute on Emit port on an Emit compound or into a Port on the ICETree node.
You can also plug it into any Execute port of a State compound, if you’re using a state system.
5. In the Emit compound, select the Shape type you want to use for the strand. This shape is repeated along the strand’s length (one shape per segment). All shape types are supported. You can see the results in the render region.
The Segment shape renders particles as strands by drawing a constant line along the length of the strand.
6. In the Generate Strand Trails property editor, you can set the maximum number of segments in the strand, multiply the strand size, set the strand size (growth rate over length of strand) using a profile curve, and loft the particle shape along the strand.
For more information on the parameters, click the ? icon in the property editor or see Generate Strand Trails.
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