Particles and Rasterization

When a group becomes rasterized, all layers within that group—including particles—are affected and may no longer interact with other layers and groups as expected.

The following examples demonstrate how rasterization affects particles in 2D groups. The first set of illustrations depicts a nonrasterized 2D group that contains a particle emitter set to the Add blend mode. The right illustration displays the particles interacting with the group beneath the emitter in the Layers tab (the group containing the “orange texture” layer). Note that the star particles interact with the pixels of the underlying group, blending with the “orange texture” light streak effect.

Figure. Layers tab and Canvas window showing an unrasterized particle group.

In the next set of illustrations, the group that contains the particle emitter is rasterized. (The rasterization is triggered by selecting the Four Corner checkbox in the group’s Properties tab.) As shown in the right illustration, the particle emitter’s Add blend mode no longer interacts with the group beneath it in the Layers tab. In the left illustration, notice that the icon for the rasterized group is now enclosed in a frame. This is called a rasterization frame.

Figure. Layers tab and Canvas window showing the rasterized particle group.

A 3D particle emitter can be rasterized independently of the group in which it lives. Consequently, the resulting particles may not interact as expected with objects inside the same group. For example, applying a Circle Blur filter to a particle emitter causes the particles to no longer intersect with other objects in the same group. The same operations that cause a 3D group to rasterize cause a 3D particle emitter to rasterize. To minimize this effect, apply the filter directly to the emitter’s source object, or deselect the 3D checkbox in the Particles tab.

Once a group or a 3D particle emitter is rasterized, the group as a whole can no longer intersect with objects outside of the group. In the following illustration on the left, the nonrasterized group that contains the particle emitter intersects with images from another group (when Render Particles is set to In Global 3D). In the illustration on the right, a Bloom filter applied to the particles group has triggered a rasterization, so the emitter no longer intersects with images from another group.

Figure. Canvas window showing how 3D particles are affected by rasterization.

Note: Unlike vector graphics, rasterized groups lose quality when scaled.

For more information on rasterization with 2D and 3D groups, see Groups and Rasterization.