The Difference Between Emitter and Particle Cell Parameters

Emitter and Particle Cell parameters, though closely related, serve different purposes. Emitter parameters control the overall shape and direction of the animated mass of particles generated by the system. Other emitter parameters simultaneously modify the parameters of all cells inside that emitter.

Particle Cell parameters, on the other hand, control the behavior of particles generated from each cell that’s inside the particle emitter. For more information, see Particle Cell Parameters in the Inspector.

When only one layer is used as a particle cell source, the cell controls appear in the Emitter tab as well as in the Particle Cell tab. Once more than one layer is added to a Particle Emitter, all cell controls appear in the Particle Cell tab. To access this tab, the cell must be selected in the Layers tab or Timeline.

To open a particle system’s Emitter tab
  1. Select an emitter object in the Layers tab, Timeline, or Canvas.

  2. In the Inspector, click the Emitter tab.

    The Emitter parameters appear.

    The contents of the Emitter tab are dynamic, and different parameters appear depending on the number of cells in the particle system, the emitter shape that’s used, and whether the 3D checkbox is selected or deselected.

Parameters in the Particle Cell tab control the behavior of particles generated by the selected cell, independently of the parameters governing the emitter. In particle systems with multiple cells, each has its own particle cell parameters. This lets you create particle systems made up of many kinds of particles, each with distinctly different behaviors.

For more information on using the Particle Cell parameters, see Particle Cell Parameters in the Inspector.

To open a cell’s Particle Cell tab
  1. Select any cell within an emitter in the Layers tab or Timeline layers list.

  2. In the Inspector, click the Particle Cell tab.

    The Particle Cell parameters appear.

    Figure. Inspector showing Particle Cell tab.

Single Cell Versus Multi-Cell Emitter Parameters

If a particle system has only one cell, the Emitter tab displays all of the parameters for the cell, as well as the emitter’s own parameters. In this case, you can control every aspect of the particle system directly from this single tab, which saves you from having to go back and forth between the Emitter and Particle Cell tabs.

Figure. Inspector showing Emitter tab for single-cell system and for a system with more than one cell.

If a particle system has two or more cells, the Emitter tab looks much different. The list of parameters is much shorter, and the majority of the cell parameters are replaced with a smaller group of master controls.

Figure. Emitter tab showing Master Controls section.

Changes made using the master controls modify the effect of each cell’s parameters relative to the other cells in the system. This means that for a particle system with three cells that have different Scale values, increasing the Scale parameter in the Emitter tab multiplies the Scale value of all three cells by the same percentage. This has the result of increasing or reducing the size of every particle in the system, while keeping the size of each particle relative to one another the same.

Figure. Canvas window showing mutliple cells being scaled relative to their original size.

For this reason, the master control parameters of multi-cell particle systems appear as percentages.