Interpolation defines the shape of an animation curve between keyframes. You can choose from the following interpolation settings depending on how you want the channel values to change over time.

LinearJoins keyframes with a straight line.

ConstantProduces a square curve. The value of one keyframe is held at a constant value until the next keyframe. This setting can produce abrupt changes between keyframes.

BezierProduces a smooth curve with a smooth transition between keyframes. Each keyframe on the curve has tangent handles. You can change the shape of the animation curve by dragging the tangent handles.

To set the interpolation type for a keyframe:

1. Select the keyframe for which you want to set the interpolation.
2. In the Animation controls, click the appropriate interpolation type button.

   
   

To create an animation curve with mixed interpolation:

1. Create an animation with at least four keyframes. Do not worry about the interpolation setting at this point.
2. Click Animation, and then click Curves to display the Channel Editor.
3. Make sure you are in Edit mode and then select the first keyframe. See Editing Keyframes.
4. Click Constant to set the interpolation for the first keyframe to Constant.
5. Select the second keyframe.
6. Click Linear.
7. Select the third keyframe, and then click Bezier.

   Your animation curve may resemble the following.