Motion Particles, replicators, and rasterization
When a group becomes rasterized, particles and replicator elements in that group are affected and may no longer interact with other layers and groups as expected. Particles and replicators still interact in 3D with elements in the rasterized group.
The following examples demonstrate how rasterization affects particles in 2D groups. In the first image, a nonrasterized 2D group that contains a particle emitter is set to the Add blend mode. The particles interact with the group beneath the emitter in the Layers list (the group containing the reddish texture). The particles blend with the pixels of the underlying group.
In the next image, the group that contains the particle emitter is rasterized. The particle emitter’s Add blend mode no longer interacts with the group beneath it in the Layers list (made apparent by the dark ring around the edges of the particles).
A 3D particle emitter can be rasterized independently of the group in which it resides. 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 to the emitter’s source object, or deselect the 3D checkbox in the Emitter Inspector.
When a group or a 3D particle emitter is rasterized, the group can no longer intersect with objects outside 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 star particles group has triggered a rasterization, so the emitter no longer intersects with images from another group.
Note: Unlike vector graphics, rasterized 2D groups may lose quality when scaled if the Fixed Resolution checkbox is selected in the Group Inspector.
In the following illustration on the left, the nonrasterized group that contains the replicator intersects with an image from another group. In the illustration on the right, a Gradient Blur filter applied to the replicator group has caused the replicator group to rasterize. As a result, the replicator no longer intersects with the image from another group.
For more information on rasterization with 2D and 3D groups, see Groups and rasterization.