Animation basics

1. About animation and keyframes

Animation is change over time. You animate a layer or an effect on a layer by making one or more of its properties change over time. For example, you can animate the Opacity property of a layer from 0% at time zero to 100% at time 1 second to make the layer fade in. Any property with a circle button to the right of its name in the Timeline panel can be animated.

A. Inactive circle B. Active circle

You can use keyframes to animate layer properties.

2. Keyframes

Keyframes are used to set parameters for motion, effects, audio, and many other properties, usually changing them over time. A keyframe marks the point in time where you specify a value for a layer property, such as spatial position, opacity. Values between keyframes are interpolated. When you use keyframes to create a change over time, you typically use at least two keyframes—one for the state at the beginning of the change, and one for the new state at the end of the change. (See Set or add keyframes.)

When the circle of a specific attribute is active, if you change the value of the attribute, the software will automatically set or change the keyframe of the attribute at the current time. If the circle for an attribute is inactive, the attribute has no keyframes. If you change the value of a layer property while the circle is inactive, the value remains the same for the duration of the layer.

If you deactivate a circle, all keyframes of the layer attribute will be deleted, and the constant value of the attribute will become the value of the current time. Do not deactivate the circle unless you are sure you want to permanently delete all keyframes of the attribute.