decorative banner

Maintaining image quality of nested compositions


    There are two methods of calculating changes to transform properties (such as rotation or scaling) during rendering of a nested composition. The default method applies transform properties and rasterizes at every level of nested compositions. The alternative method, collapsing transformations, postpones the calculation of transform properties and rasterization of nested compositions until the rendering process reaches a layer you select. (You cannot collapse a layer's transform properties if a mask or effect is applied to it.) You can increase image quality and significantly reduce rendering time by collapsing transformations.

To collapse transformations of a nested composition:

    In the Layer Feature panel of the Timeline window, click the Collapse Transformations switch icon next to the layer containing the nested composition.

    Collapsing transformations can preserve resolution when a nested composition is scaled down and then scaled back up in successive compositions. Without collapsed transformations, a nested composition that is scaled down loses the resolution of its original larger size. When you collapse transformations, the original resolution of a nested composition is preserved; its final resolution is determined by its size within the composition that uses collapsed transformations.

    Default method When a nested composition is scaled down and then up again in successive compositions, it retains the lower resolution of the scaled-down version.
    Default method When a nested composition is scaled down and then up again in successive compositions, it retains the lower resolution of the scaled-down version.
    Collapsed transformation When a nested composition is scaled down and then up again in successive compositions, it retains the resolution of the original layer.
    Collapsed transformation When a nested composition is scaled down and then up again in successive compositions, it retains the resolution of the original layer.

    When you collapse the transform properties of a layer, all compositions nested inside it combine their opacity setting with the opacity setting of the layer that uses collapsed transform properties.

    Because you can collapse transformations but not mask or effect properties, After Effects automatically disables all composition and layer switches related to masks or effects when you collapse transformations. If you click a disabled layer switch, After Effects prompts you to turn off Collapse Transformations. You cannot turn on the Effect, Mask, Mask Feather, or Motion Blur layer properties or apply transfer controls to a layer in which you collapsed transform properties. You can still apply these properties to a composition nested within the composition with transform properties collapsed, as long as the Collapse Transformations switch is not turned on for that composition.

    When a layer contains an Adobe Illustrator file instead of a nested composition, the Collapse Transformations switch for that layer becomes the Continuously Rasterize switch, which you can use to improve the image quality of footage. See Importing an Adobe Illustrator, PDF, or EPS file and Collapsing transformation properties.

    Collapsing transformations also adds some flexibility when you work with 3D layers in nested compositions. If you have a subordinate composition that has 3D objects within it without Collapse Transformations, After Effects renders the composition as a 2D image of the 3D arrangement in the higher composition. However, if you turn on Collapse Transformations, After Effects renders the 3D layers into the next higher composition so that they retain their 3D relationships among themselves and with other 3D layers in the higher composition. You can continue to manipulate the relative positions of the 3D layers from the lower composition as a group.