Using the Particle Operation

The Particle operation is used to clone objects. This is a good way to create a forest from a single tree or a lawn from a single blade of grass.

This cloning process can be animated so that a single smoke particle can be become a trail of smoke from an engine or smoke coming from a fire.

Modeling

Various effects such as scaling, rotating and translating (moving) can be applied to each object clone. Instead of a simple static effect being applied to each clone, each clone is given a random effect within a specified range. So for instance if you were to enter -10 to 10 in the Translate X section each object would be translated between -10 and 10 units along the X axis. The result would be a random distribution of between -10 and 10 units.

The Translate effect is in 3D Canvas units, the Rotate effect is in degrees, and the remaining effects are in percent. So for instance a range of -20 to 20 in the Scale X section means scale the object between -20% and 20% along the X axis. Note that if an object has no X width it will not get larger since 0 * 120% = 0. This is true of all effects that use percentages. If an object has no red component in its color you will not be able to affect the red component of the color.

Animation

Animation provides many more options but the above description still applies. The big difference is that rather than having a large number of particles created all at once, the particles are generated during the animation. The Generation Frequency indicates how many particles are generated for every animation key-frame. Note that particles are not generated until the first key-frame of animation for the object's frame. So if the frame doesn't have any key-frames until time 5 there will be no particles cloned until time 5.

In addition to setting an initial range of effect you can also set a velocity and acceleration for the effect. So, for example you could have a particle be scaled a small amount when it is first created, but as the animation runs the particle could get larger and the rate of which it gets larger could increase.

The Generation Duration is the length of time (in key-frames) during which particles are generated. You can also specify a Life Span which is the length of time that the particle lives. Note that this is a range so that particles disappear at varying times.

Particles can be generated using two different methods. The particles can be emitted, which means that they are dropped along the path of the animation, or they can follow the animation path of the particle's frame. Emitted particles are particularly useful for smoke trails that are emitted from an object.

Animating particles can be very slow, so it is important to remember to use as few particles as possible when designing the particle effect and then increase the number of particles for the final rendering.