Particle
Defines the properties of the particles that Form uses to construct visuals in 3D space.
Particle Type
There are 8 different particle types with 5 built-in shapes (sphere, glow sphere, Star, Cloudlet and Smokelet) and 3 options for custom particles based on a separate layer in the After Effects composition. Here are the 8 types:

| Sphere Basic round particle. Control softness with Sphere Feather. |  |  | Smokelet A shadowed variant of Cloudlet. Control with Rotation/Smokelet Feather.
| Glow Sphere Glowing round particle. Control center sphere softness with Feather. The glow settings are in Options. |  |  | Custom Use any layer as particle.
| Star Star-shaped particle with glow. Control rotation with Rotation. The glow settings are in Options. |  |  | Custom Colorize Same as Custom, but adds the ability to colorize the particles using lightness.
| Cloudlet A randomized shape that looks like a small cloud. Control with Rotation/Cloudlet Feather. |  |  | Custom Fill Same as Custom but adds the ability to colorize the particles by filling the masked alpha region with a single color.

Sphere Feather
Controls the amount of feather (softness) for the sphere particle, where 0 will set no softness and the sphere will appear distinct, and a value of 100 will cause the spheres to appear soft and blend into the surrounding particles.
Custom
This sub-group can be twirled open to control custom particles only when the Custom, Custom Colorize or the Custom Fill options are chosen from the Particle type pop-up. The ability to use custom particles provides infinite flexibility in producing particle effects. You can even use a logo or any movie as the source shape: the Form grid will be made up of particles from each frame of the movie. The possibilities are endless.
If there are any effects or masks applied to the custom particle layer, it will need to be pre-composed (Layer>Pre-Compose). If the effects are complex, it is a good idea to pre-render the particle to a movie file and then bring this pre-rendered movie into the composition. Try to keep layer size as small as possible, no larger than 100x100 pixels is recommended. A rule of thumb for custom particle layer size is to keep the layer the same size as the largest visible particle. If the custom particle layer is larger than that, than long render times will result, as Form must resize and position these large particles.
Custom particle layers must always start at the same frame as the layer Trapcode Form is applied to.
Custom Layer
This pop-up lets you specify a separate layer as an input to the Particle. For example, you could create a logo made up of tiny particles of the logo itself that would become visible as the camera zooms towards the form.
Time Sampling Modes
>Time Sampling mode should generally be set to "Current Time" (the default). This will speed up rendering because the same frame of the layer is used for all particles in the current frame. If using any of the other modes, you can drastically reduce render time by pre-rendering the custom particle layer.
When using an animated particle, the other modes are sometimes useful:

Random - Still Frame | Grabs a random frame from the custom layer and uses it throughout the particle's life.
Random - Loop | Starts playing the custom layer from a random frame, and then plays at normal speed. If the custom layer ends, it re-starts from the beginning.
Split Clip - Loop | Randomly selects one of the clips and plays the clip looping.

The Split Clip mode splits the custom layer into a number of clips specified by the "Number of Clips" setting. For example, if the custom layer is 150 frames and "Number of Clips" is set to five, that means it will be split into five 25-frame clips. This is useful for creating a set of animated particles that are placed randomly in the grid and at each loop.
Example for Time Sampling Modes
Here is an example of a custom particle that we will use as the particle source.
Example 1:
Now we will apply this to a simple sphere form with 10 Particles in X and 10 Particles in Y. In this example, the Particle Time Sampling is set to Random Still Frame. Each particle is a single random frame from the movie above and does not change.
Example 2:
Here is the same Form example but, the Particle Time Sampling is set to Random Loop. Each particle starts at a random frame from the movie above and changes constantly so the animation is much more chaotic.
Example 3:
Here is the same Form example, but the Particle Time Sampling is set to Split Clip - Loop and the Number of Clips is 5. Each particle starts randomly at 0, 1, 2, 3, or 4 seconds into the source movie above, and only changes by using 1 second of the source movie as a particle. The motion is more random than the first example, but less so than the second, because the shapes stay the same in the 1-second loop that Form uses as a source.
Rotation
Adjusts the 2D rotation of the particle around the Z axis.
Size
Sets the particle size in absolute pixels for both standard particle types and custom particles.
Size Random
Sets randomness for particle size. A value of 0 means no randomness, and a value of 100 will vary the opacity between the minimum and current particle size settings.
Opacity
Set opacity for particle. A value of 100 means the particle is completely opaque, while a value of 0 will make the particle completely transparent.
Opacity Random
Sets randomness for particle opacity. A value of 0 means no randomness, and a value of 100 will vary the opacity between the minimum and current opacity settings.
Color
Defines the color of the particle. Note that this color can be superceded by Quick Maps and Layer Maps.
Transfer Mode
Sets the transfer mode of the particle. This works much like blending modes in After Effects, except the individual particles behave like layers in 3D space. (For more information on the individual modes, see the After Effects online help's Blending Mode Reference section.) Normal transfer mode means that opaque particles will block particles behind them along the Z axis. Screen mode often results in a brighter look than Normal, and disregards depth information. Add gives an even brighter look than Normal or Screen and also disregards depth values. Lighten means particles are composited in order along the Z axis, but only pixels that are brighter than those behind them are written.