Creating a particle system from scratch begins with designing the particles you want it to emit. You can use any image, shape, text, or movie supported by Motion as a source for a cell. This section presents guidelines for creating particle imagery.
Particle systems that use still images as their cell sources render in real time much faster than systems that use video or animation clips. A still image is often all you need to create a compelling particle system. Here are some guidelines for creating graphics for use as particles.
If you are unsure what size you want your particles to be, it’s a good idea to make your graphics larger rather than smaller. Increasing the size of particles beyond the size of the original graphic can introduce unwanted artifacts. One caveat, however, is that the larger the cell source size, the slower your playback performance.
The quality of the edges of your graphics can be extremely important for creating convincing particles. Soft, translucent edges might look better than hard, over-defined ones.
By default, particles are created using the original colors of the image used as the cell. If necessary, you can tint the emitted particles using the Color Mode parameters in the Emitter and Particle Cell Inspectors. Choose between tinting all particles with a single color or creating a gradient tint that changes color over time. You can also choose to apply a Library gradient to the particles. Tinting particles applies the tint color uniformly over the entire particle system.
Always create graphics that you want to use as cells with predefined alpha channels. For more information on importing files with alpha channels, see More About Alpha Channels.
You can also use QuickTime movies as cells. For example, you can create an animation in Motion, render it as a QuickTime movie, and import it into another Motion project to use as a cell. In general, the same recommendations for creating still graphics apply to the creation of animation or video clips you intend to use as cells, but there are additional considerations.
If a clip is retimed in the Properties Inspector or with a Retiming behavior, the effect of the retiming is carried through to the particle system.
Note: Using a movie as the source cell for an emitter can impact your project’s playback performance.
Particles created from QuickTime clips loop over and over for the duration of each particle’s life. If the clip you use doesn’t loop well, there will be a jump cut at every loop point. Another option is to use very short movies to introduce randomness into the appearance of the particle system.
Ideally, QuickTime clips to be used as particles should be saved using a high-quality codec, such as Animation, Uncompressed 8- and 10-bit 4:2:2, or ProRes 4444. Other codecs can be used, but they might introduce unwanted artifacts depending on the level of compression used.
There is an option to use random start frames, which causes the clips to play out of sync relative to one another in the Canvas. There is also an option to play or not play the clip.