From VFXPedia

Particle System Common Controls

There are a variety of controls that are common to all of the Particle tools. These controls generally provide mechanisms for limiting the effect of the Particle tool. They are organized into three tabs.

Controls Tab

One control that is seen in almost all of the Particle tools is the Random Seed value. The Seed value is often used to set up the initial conditions for calculations with a random component. Using the same seed value will ensure that the same set of random values is produced by the calculation.

Since many of the Particle tools use random elements as part of their calculations, changing a seed value is often a good way to slightly modify the results of a tool.

Conditions Tab

This control determines the Probability or percentage chance that the tool will affect any given particle.

The default value of 1.0 will affect all particles. A setting of 0.6 would mean that each particle has a 60 percent chance of being affected by the control.

Probability is calculated for each particle on each frame. For example, a particle that is not affected by a force on one frame has the same chance of being affected on the next frame.

This range control can be used to restrict the effect of the tool to a specified percentage of the particle lifespan.

For example, to restrict the affect of a tool to the last 20 percent of a particle's life, set the start value to 0.8 and the end value remains at 1.0. The tool on frames 80 through 100 only affect a particle with a lifespan of 100 frames.

This menu control determines if the particle tool's effect will be applied to all particles, limited only to particles from a specified set(s), or applied to all particles except the selected set(s).

Sets are assigned by the tools that create particles: the pEmitter, pImage Emitter, the pChangeStyle and the pSpawn tools.

Region Tab

Regions are used to restrict the tool's effect to a geometric region or plane, and to determine the area where particles are created in a pEmitter tool. There are seven types of regions, each with its own controls.

All

In 2D, the Particles will be created anywhere within the boundaries of the image. In 3D, this region describes a cube 1.0 x 1.0 x 1.0 units in size.

Bezier

Bezier mode uses a user-created polyline to determine the region where particles are created. The Bezier mode works in both 2D and 3D modes, however the Bezier polyline region can only be created in 2D.

To animate the shape of the polyline over time or to connect this polyline to another polyline, right-click on the Polyline label at the bottom of the control and select the appropriate option from the context menu.

Bitmap

A Bitmap source from one of the other tools in the composition will be used as the region where particles are born.

Cube

A full 3D Cube is used to determine the region within which particles are created. The height, width, depth and XYZ positions can all be determined by the user and animated over time.

Line

A simple Line control determines where particles are created. The Line is composed of two end-points, which can be connected to Paths or Trackers, as necessary. As with Bezier, this region type works in 3D but the line itself can only be created and adjusted in 2D.

Rectangle

The Rectangle region type is like the Cube type, except that this region has no depth in Z space. Unlike other 2D emitter regions, this region can be positioned and rotated in Z space.

Sphere (3D)

This is a spherical 3D emitter region with size and center Z controls. Sphere (3D) is the default region type for a new pEmitter tool.

Tips for Common Particle Controls (edit)

EyeonTips:Manual/Tool Reference/Particles/Common Particle Controls

The contents of this page are copyright by eyeon Software.