Collapsing transformations to maintain image quality

There are two methods of calculating changes to transform properties (such as rotation or scale) while rendering a nested composition. The default method is to apply transform properties and rasterize at every level of nested compositions. The alternative method is to collapse transformations, which postpones the calculation of transform properties and the rasterization of nested compositions until the rendering process reaches a layer you select. You can increase image quality and significantly reduce rendering time by collapsing transformations.

To collapse transformations of a nested composition:

In the Layer Feature column 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.

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.

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 turning on Collapse Transformations, After Effects renders the composition as a 2D image of the 3D arrangement in the next 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 there. You can continue to manipulate the relative positions of the 3D layers as a group from the lower composition.