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:

1. Select a channel or group of keyframes.
2. From the Curve Functions box in the Keyframe tab, select Tangent R to rotate each right tangent handle or Tangent L to rotate each left handle.

   
   

   NoteTangent R and Tangent L only work on curves and keyframes that use Hermite or Natural interpolation. See Setting Interpolation.
3. Enter a value in the 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.