Particle group> Texture group

The Texture group lets you select a layer to be used as a custom particle texture. It also sets the particle texture's behavior, such as specifying which frame of the layer to sample from. The particle types that use particle textures are the Sprite and Textured Polygon options in the Particle Type menu. All layers or pre-composed layers are valid inputs. You can use a bitmapped image, a shape layer, a movie or a pre-comp. If you are using a text layer, that layer must be pre-comped.

Version 1.5 Note: The Texture group used to be called Custom Layer. Its controls work much the same as they did before, with one additional Time Sampling mode.

The full Texture group controls.

Layer

The Layer menu specifies the source layer that will be used as a texture or custom particle. All other Texture group controls affect the image content loaded form the layer source.

By default, the Layer pop-up is set to None and turned off. To turn it on, just choose a layer from the pop-up box. This layer must be in your Timeline, and the View (eye icon) can be turned off for that layer.

The Layer pop-up shows all available layers.

Those layers are present but turned off in the Timeline.

Layer input as a Textured Polygon

Here is an example of Layer applying a custom particle.

A 'Crescent' bitmap is loaded as a layer in the After Effects Timeline.

The Crescent layer loaded into the Layer popup.

The composition with crescent shapes emitted as Textured Polygons.

If you try to apply a layer that is really large (comp-sized, for example), a warning message will appear. This warning will tell you to use a smaller layer. Small layers will render much faster and avoid out-of-memory issues with large emission rates.

The Particular warning dialog shown when a large layer is chosen as a Layer input.

Time Sampling

Time Sampling determines which frame of the layer is sampled to generate the Texture. There are eleven modes. The mode determines which frame the texture is sampled from with options for starting from the first frame, picking a random frame, or splitting the layer source into multiple clips.

The default choice is Current Time. If the custom particle is a still image, the mode should always be set to Current Time. This option will speed up rendering because the same frame of the layer is used for all particles in the current frame.

When using an animated particle, the other modes are useful. The Start, Random and Split modes can drastically reduce the time needed to pre-render the custom particle layer. Following is an explanation of how each works.

The Start modes all begin at frame one (the 'start') of the custom input layer.

Start at Birth - Play Once | This mode samples the custom layer from the first frame once. The particle may die before the custom layer ends, or the custom layer may end before the particle dies. If the layer does not have the same timespan as the particle life, then particles will stop appearing because no source particle is available to Particular.
Start at Birth - Loop | This mode samples the custom layer from the first frame and restarts (or loops) if the layer ends. By looping the content of the layer source, a constant stream of particles will appear for layers that are shorter than the Particular emission layer.
Start at Birth - Stretch | This mode samples the custom layer from the first frame and time-stretches it so it ends exactly when the particle dies. For example, if the layer source has a timespan of 1 sec and the Particle Life [sec] is set to 3.0, then Particular will stretch the layer source content by duplicating the input layer frames to make its timespan match the 3-second particle life.

The Random modes pick a frame at random to use.

Random - Still Frame | This mode selects a single random frame from the source layer and uses it throughout the particle's life.
Random - Play Once | This mode starts sampling the source layer from a random frame, and then plays at normal speed. If the layer does not have the same timespan as the particle life, then particles will stop appearing because no source particle is available to Particular. This mode is similar to the Start at Birth - Play Once mode, but starts from a random point in time for the particle source.
Random - Loop | Starts playing the custom layer from a random frame, and then plays at normal speed. If the custom layer ends, it loops and restarts from the beginning. By looping the content of the layer source, a constant stream of particles will appear for layers that are shorter than the Particular emission layer. The loop will return to the same random start frame for each particle.

Split Clip modes split the custom layer into a number of clips. The number is set with the Number of Clips control. For example, if the custom layer is 30 frames and Number of Clips is set to 3, that means the custom layer will be split into three 10-frame clips. This is useful for creating a set of animated particles from one layer source.

Split Clip - Play Once | This mode randomly selects one of the clips and plays the clip once. If the layer does not have the same timespan as the particle life, then particles will stop appearing because no source particle is available to Particular.
Split Clip - Loop | This mode randomly selects one of the clips and plays the clip, looping for the span of the clip.
Split Clip - Stretch | This mode randomly selects one of the clips and time-stretches it to fit the particle life. This mode is similar to the Start at Birth - Stretch mode, but it works on the content of the split clips instead of the entire source layer.

There is a new option called Current Frame Freeze in version 2.0.

Current Frame Freeze | Holds the referenced particle image at the current time throughout the particle's life. Any particles born at a certain frame will have that same appearance throughout the particle's life, even though the input layer may be animating. This happens at each frame.

Random Seed (new to version 2.0)

This control is active when any of the Random or Split Clip modes are chosen in the Time Sampling menu. Random Seed samples from a random start frame without changing the positions of the particles.

Number of Clips

Active when any of the Split Clip modes are chosen in the Time Sampling pop-up. This control defines the number of clips in the custom layer that the Split Clip mode will use.

For example, you may have five movies that are 10 frames each in a pre-comp. You may then select a Split Clip mode and set Number of Clips to 5. This will tell Particular to use just one of the five clips as the texture source for the particle simulation.

Subframe Sampling

This control is active when any of the Play Once, Stretch, or Still Frame modes are chosen in the Time Sampling pop-up. This allows subframe sampling for the custom particle layer. This is useless if the custom particle is a movie, but if it is an animation, the plug-in can retrieve frames that are in-between frames.