Modifying Tangents to Reshape the Animation Curve
To modify the tangents of an animation curve:
From the Tangents drop-down, select Auto.
From the Interpolation drop-down, select an interpolation type. Only animation curves that use Bézier, Hermite, or Natural interpolation have keyframes with tangent handles.
From the Tools drop-down, choose Select and move the tangent handles.
As you move the handles, the slope on each side of the keyframe is modified independently.
Note: You must break tangent handles to move them independently. From the Tools drop-down, select Break Tangents and click the tangents you want to break.
To modify the tangents of an animation curve:
From the Interpolation drop-down, select an interpolation type. Only animation curves that use Bézier, Hermite, or Natural interpolation have keyframes with tangent handles.
From the Tools drop-down, choose Select and move the tangent handles.
As you move the handles, the slope on each side of the keyframe is modified independently.
Note: You must break tangent handles to move them independently. From the Tools drop-down, select Break Tangents and click the tangents you want to break.
If the tangents are not visible:
- Set the Interpolation mode to Bezier, Hermite, or Natural. Keyframes set to Linear or Constant interpolation do not have tangents.
To reset tangents to their default:
- From the Tools drop-down, select Auto Tangent.
- Click the handle of the tangent you want to reset.
Modifying Multiple Tangents
You can modify the shape of an animation curve by rotating its keyframe tangent handles.
To rotate a keyframe's tangent handles:
Select a channel or group of keyframes.
From the Curve Functions drop-down in the Keyframe tab, select Tangent R to rotate each right tangent handle or Tangent L to rotate each left handle.
Note: Tangent R and Tangent L only work on curves and keyframes that use Bézier, Hermite, or Natural interpolation. Select your option from the Interpolation drop-down.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.
More on Tangents
The control handle of a tangent tells you if its a Fixed (filled handle) or Smooth (empty handle) tangent.

Fixed Tangent handles

Smooth Tangent handles
While its true that Linear and Constant interpolations do not display tangents, a keyframe displays a mix of tangent types when the interpolation changes from one type to another.
