About dynamic resolution

As you drag layers in the Composition window, or use the Manual Preview option, After Effects dynamically updates each frame in the Composition window. If necessary, After Effects dynamically degrades the resolution of the layer. This reduces the amount of data that needs to be compiled during the edit and thereby facilitates a smooth, quick update. Once the update is complete, the layer returns to the designated composition resolution. You can set the maximum level of degradation to apply to a layer.

To set dynamic resolution:

1. Choose Edit > Preferences > Previews.
2. Select the Use Dynamic Resolution option to turn dynamic resolution on or off.

To set the degradation limit:

1. Turn on dynamic resolution as outlined in the above procedure.
2. Click the Degradation Limit menu and select an option. The options represent the maximum fraction of data removed from a layer's current composition resolution when After Effects enacts dynamic resolution.