Autodesk 62205-051408-9001 User Guide - Page 353

Particles Operator Interface ❚❘❘ Preload Frames Preload Frames is the number of frames that you want the emitter to emit before it activates. By default, emitters start emitting particles from the frame where the emitter is added to the clip. At first there are no particles, then you see the first particles emerge. For example, if the scene requires a waterfall or a smoking fire, these emitters should be fully emitting the moment they start; you do not want the amount of particles to start increasing only at the first frame. Active Emitter This property determines when an emitter is on (creating particles) and off. When an emitter turns off, all its particles disappear instantly. Note: There are very few cases where you animate the Active Emitter property. Usually, you want particles to linger and fade out, so you animate Number instead. If you add an emitter at frame 20, Active Emitter is disabled until frame 20, from which point it remains enabled. Preserve Alpha Preserves the transparency (alpha channel) of the Footage operator or image stream that is the input for the Particles operator. Ignore Motion Blur Enable this option so motion blur is not calculated for the selected emitter. If it is disabled and the Enable option in the Global Motion Blur settings (in the Settings controls) is turned on, then motion blur is calculated. Particle Ordering The Particle Ordering list includes None, Oldest in Back, and Oldest in Front. Particle Ordering list Particle ordering is a way of overriding how the Particles operator manages memory for new and dead particles. Use this feature only in special cases where the exact method of freeing up memory makes a difference to the look of a particle effect. Note: You should use Particle Ordering only when necessary because it uses more memory. Usually, you should leave it set to None. When a new particle is created by an emitter, the particle is added to a drawing list in memory. Drawing starts with the first particle in the list and ends with the last. Initially, this means that the oldest particles are drawn first, and the newest particles are drawn last. After some time, the life of some of the particles expires. To conserve memory, the dead particles are reused by creating new particles from them. The new particle remains in the same place in the drawing list, so some of the newer particles are being drawn before some of the older particles; the drawing list is no longer in order. As more time passes and more particles die, the drawing list becomes disordered. In most cases, this mixing up of the drawing list makes no difference; the particles appear the same regardless of the order in which they are drawn. In some cases, though, the order that the particles are drawn in does make a difference. For Oldest in Back, the oldest particles are drawn first so the emitter appears to be coming toward you. For Oldest in Front, the newest particles are drawn 337