Editing Key Tangents

When Show Tangents is on, the Curve Editor displays tangent handles for selected keys.

• Track View > Curve Editor > Curves Toolbar > Show Tangents

By default, all key tangents are set to Auto and Show Tangents is on, so the tangents are drawn as blue dashed handles emanating from highlighted keys in the Key window of Track View. If the Move tool is active, you can adjust the shape of a function curve near the key by dragging the handle endpoints. For more information about tangents, see Tangent Types.

When you move the handle of an Auto tangent, the tangent type is automatically changed to Spline, as indicated by the color changing to black. You can change the tangent type for all highlighted keys at any time with the controls on the Key Tangents toolbar and the Tangents menu.

Spline Tangent

You can assign the Spline tangent type to any visible key in the Curve Editor. Highlight the key and then click the Set Tangents to Spline button on the Key Tangents: Track View toolbar to display the handle controls. Also, moving an Auto tangent handle automatically changes the type to Spline.

Tangent handles can be either continuous (unified) or discontinuous (broken).

• Continuous handles move as a single lever with its pivot point at the key location. Moving either handle also moves the opposite end, maintaining the continuity of the tangent.

  To make a key's handles continuous, highlight the key and click Unify Tangents on the Tangent Actions toolbar (or choose Unify Tangents from the Tangents menu).

• Discontinuous handles behave like leaves on a hinge, with the hinge pin at the key location. Each end moves independently of the other.

  To make a key's handles discontinuous, highlight the key and click Break Tangents on the Tangent Actions toolbar (or the Tangents menu), or hold down the Shift key when you move a handle.

Horizontal Bezier Handle Control

You can change the shape of the function curve around a key set to Spline tangent type by moving the tangent handle along its length. This affects the amount of influence the keyframe has over the interpolation between keyframes.

You can use this feature to aid in the slow-in and slow-out workflow of traditional animation. For example, suppose you're animating a ball bouncing up and down on the world’s Z axis. At frame 1, the ball is on the ground; at frame 8, the ball is in the air; and at frame 16 the ball is back on the ground. You could adjust the tangents for frame 8 so that their length pulls more of the curve towards its keyframe and away from the keyframes on frame 1 and 16. When rendered, the ball will be more visible on screen near the top of its bounce and blurrier near the points where it touches the ground.

Procedures

To assign a Spline tangent type:

1. Open the Curve Editor.
2. In the Hierarchy list, highlight one or more tracks that contain keys.
3. Highlight one or more keys on the curves.
4. On the Key Tangents: Track View toolbar, click Set Tangents to Spline.

   The handles are now all Spline and available for editing.

   Tip: If a highlighted key is set to Auto tangent, you can just move its handle to instantly convert the key to Spline tangent.

To edit the length of a Bezier handle:

1. Assign a Spline tangent type to the key you want to edit on the function curve, or highlight a key that already has one.
2. Make sure Show Tangents is on. This toggle is located on the Track View toolbar.
3. Highlight the key on the function curve.

   Tangent handles appear on the highlighted keyframe.

4. Move one of the handles horizontally away from its key.

Common tools for working with tangents

The following table provides a brief overview of available tools to help you work with tangents. The tools can be found on the Key Tangents, Tangent Actions, Curves, Tangent Tools, and New Key Tools toolbars.

Tool	Description
View All Tangents (Curves)	Hides/displays all tangent handles on all curves.
Show Tangents Toggle (Tangent Actions toolbar, Curves)	Hides/displays tangent handles.
Break Tangents (Tangent Actions)	Allows the two tangents connected to a key to be moved separately.
Unify Tangents (Tangent Actions)	Unifies broken tangents, maintaining the minimum angle between handles.
Lock Tangents Toggle (Tangent Actions, Curve)	Locks the tangents so they cannot be modified.
Scale Tangents Up (Tangent Tools, New Key Tools)	Increases selected keys' tangents. Press Shift to only increase inner tangents when multiple selected.
Scale Tangents Down (Tangent Tools, New Key Tools)	Decreases selected keys' tangents. Press Shift to only decrease inner tangents when multiple selected.
Mirror Tangents (Tangent Tools, New Key Tools)	Mirrors the selected key's tangents to adjacent keys.
Set Tangents to Auto (Key Tangents)	Sets selected keys to automatic tangents, as calculated by the shape of the function curve around the key.
Set In Tangents to Auto (Key Tangents)	Sets selected keys' incoming tangents to automatic tangents.
Set Out Tangents to Auto (Key Tangents)	Sets selected keys' outgoing tangents to automatic tangents.
Set Tangents to Spline (Key Tangents)	Sets selected keys to spline tangent. Press Shift to break continuity when editing handles.
Set In Tangents to Spline (Key Tangents)	Sets selected keys' incoming tangents to spline tangents.
Set Out Tangents to Spline (Key Tangents)	Sets selected keys' outgoing tangents to spline tangents.
Set Tangents to Fast (Key Tangents)	Sets key tangency to fast.
Set In Tangents to Fast (Key Tangents)	Sets selected keys' incoming tangents to fast.
Set Out Tangents to Fast (Key Tangents)	Sets selected keys' outgoing tangents to fast.
Set Tangents to Slow (Key Tangents)	Sets key tangency to slow.
Set In Tangents to Slow (Key Tangents)	Sets selected keys' incoming tangents to slow.
Set Out Tangents to Slow (Key Tangents)	Sets selected keys' outgoing tangents to slow.
Set Tangents to Step (Key Tangents)	Sets key tangency to step.
Set In Tangents to Step (Key Tangents)	Sets selected keys' incoming tangents to step.
Set Out Tangents to Step (Key Tangents)	Sets selected keys' outgoing tangents to step.
Set Tangents to Linear (Key Tangents)	Sets key tangency to linear.
Set In Tangents to Linear (Key Tangents)	Sets selected keys' incoming tangents to linear.
Set Out Tangents to Linear (Key Tangents)	Sets selected keys' outgoing tangents to linear.
Set Tangents to Smooth (Key Tangents)	Sets key tangency to smooth.
Set In Tangents to Smooth (Key Tangents)	Sets selected keys' incoming tangents to smooth.
Set Out Tangents to Smooth (Key Tangents)	Sets selected keys' outgoing tangents to smooth.