Using Dynamic Preview

When you disable Dynamic Preview, After Effects displays wireframe representations instead of the actual layer while you move the layer in the Composition window. The layer appears again after you stop moving it.

To enable or disable Dynamic Preview mode:

Click the Disable Dynamic Preview button  in the Timeline window.

To temporarily disable or enable Dynamic Preview mode:

Hold down Alt (Windows) or Option (Mac OS) as you move a layer.

To specify the Dynamic Preview preferences:

Choose Edit > Preferences > Previews (Windows) or After Effects > Preferences > Previews (Mac OS), and select Enable Dynamic Preview.