Layers

Layer

There are several layer types, which is specified by the ty attribute:

Each layer type has its own properties but there are several common properties:

Note that layers that don't have a visual component (Audio layers for example), won't have a transform and similar.

The layer is only visible between its ip and op. If they match the corresponding attributes in Animation, the layer will be visible the whole time, otherwise it will become visible at the frame ip and disappear at op.

Parenting

Within a list of layers, the ind attribute (if present) must be unique.

Layers having a parent attribute matching another layer will inherit their parent's transform (except for opacity).

Basically you need multiply the transform matrix by the parent's transform matrix to get a child layer's final transform.

The flat layer structure and flexible parenting allows more flexibility but it's different from the more traditional approach of nesting child layers inside the parent layer (like a folder structure).

One of the advantages of flexible parenting is you can have children of the same layer be intermixed with unrelated layers.

In the following example, the star and the ellipse are in separate layers, but both have the same parent, which moves left and right. Between the two there's an additional layer with the rectangle.

Auto Orient

When true, if the transform position is animated, it rotates the layer along the path the position follows.

In the following example there are two arrows animated along the same path, with no rotation when the position moves towards the right.

The transparent one keeps its rotation the same (ao is 0), while the solid one follows the path (ao is 1).

Mattes

A matte allows using a layer as a mask for another layer.

The way it works is the layer defining the mask has a tt attribute with the appropriate value. By defaults it affects the layer on top (the layer before it in the layer list, which has the td attribute), otherwise check the tp attribute.

In this example there's a layer with a rectangle and a star being masked by an ellipse:

Masks

A layer can have an array of masks that clip the contents of the layer to a shape.

This is similar to mattes, but there are a few differences.

With mattes, you use a layer to define the clipping area, while with masks you use an animated bezier curve.

Shape Layer

Renders vector data.

The only special property for this layer is shapes, an array of shapes.

Precomposition Layer

This layer renders a precomposition.

You can find more details in the Precompositions page.

Time remapping

The tm property maps the time in seconds of the precomposition to show.

Basically you get the value of tm at the current frame, then assume that's a time in seconds since the start of the animation, and render the corresponding frame of the precomposition.

Follows an example of this, here there are two layers showing the same precomposition, the one at the top right keeps the original time while the bottom one remaps time as follows:

• frame 0 (0s) maps to 0s (frame 0) in the precomp
• frame 30 (0.5s) maps to 3s (frame 180) in the precomp
• frame 60 (1s) maps to 1.5s (frame 90) in the precomp
• frame 180 (3s) maps to 3s (frame 180) in the precomp

Basically it makes the precomp play in the first half second, then rewind to half way for the next half second, and plays back to the end for the remaining 2 seconds.

Null Layer

This layer doesn't have any special properties.

It's often used by animators as a parent to multiple other layers (see parenting).

Text Layer

For text data, please refer to the section about text for details.

Image Layer

This layer renders a static image.

Solid Color Layer

This layer represents a rectangle with a single color.

Anything you can do with solid layers, you can do better with a shape layer and a rectangle shape since none of this layer's own properties can be animated.

Note that the color is represented as a string, unlike most other places.

Audio Layer

This layer plays a sound.

Audio Settings

3D Layers

Layers can have 3D transforms as well:

3D layers need to have the ddd set to 1 (and so does the top-level object).

Their transform will habe a and p specified as 3D components.

Rotation will be split into 3 properties: rx, ry, rz, and you have and additional orientation property or.

Camera Layer

Camera for 3D layers.

3D Parenting

As with 2D layers, you can parent 3D layers.

Data Layer

This layer links to a data source.