You can modify the shape of an animation curve by rotating its keyframe tangent handles to control the smoothness and speed of the animation.
To rotate a keyframe's tangent handles:
(a) Curve Functions box (b) Curve Value field
A negative value rotates each tangent counter-clockwise. A positive value rotates each tangent clockwise.
The tangent handle first breaks into two and then the handles are rotated.
The following example shows the results of applying Tangent L with a rotation value of 36 to the keyframes of an entire curve. No keyframes were broken before Tangent L was applied.
(a) The curve before applying Tangent L. Note that none of the keyframes are broken.
(a) The curve after applying Tangent L of 36. A break is applied to all keyframes before the tangents are rotated.