Using the Curves Tab

At the bottom of the Graph Editor interface is the Curves tab. Here you can adjust the value of a selected keyframe and its pre- and post-behaviors. This area is ghosted until a keyframe is selected. For example, suppose that you have created a spinning globe that takes 200 frames to make a full 360-degree revolution. Your total scene length is 600 frames and the globe needs to rotate throughout the animation. Instead of setting additional keyframes for the globe, you can set the post-behavior to repeat. Once the globe completes its 200 frames of motion, the Graph Editor’s post-behavior takes over. You can also set pre-behaviors. A pre-behavior is what happens before the first keyframe.

You can set either pre- or post-behaviors to the following settings: