Key Properties

Owned by thomas (Unlicensed)
Last updated: 15 Aug, 2016

 

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By clicking on the arrows you can go through a curve's keys, while the current index number is shown in the field.

Frame

Enter any value to set a new time for the selected key. “Frame” depends on “Toggle Frames or Time View”, and therefore either uses frames or seconds.

Value

Here you can change the selected key's associated parameter value at the current time.

Pre-Behaviour

Here are the options:

  • “Zero”. The parameter's value is set to 0 until the first key.
  • “Constant”. This function uses the first key's parameter value.
Post-Behaviour

Here are the options (images of the various behaviours can be seen → here):

  • “Zero”. The parameter's value is set to 0 after the last key to continue the curve.
  • “Constant. “The last key's parameter value is used to continue the curve.
  • “Loop”. Creates an endless repetition of the curve segment between the first and the last key to continue the curve.
  • “Loop offset”. Creates an endless repetition of the curve segment between the first and the last key to continue the curve: the values are added and the result is a growing curve.
  • “Follow tangent”. Uses the last key’s tangent gradient to continue the curve.
Key Type

There are four types: “Tcb”, “Bezier”, “Linear” and “Stepped”. “Tcb” is controlled with the “Tension”, “Continuity”, and “Bias” parameters.

Ease To/Ease From

Both parameters are used to create a smooth acceleration or deceleration. Valid values range between 0.0 and 1.0.

Tension

Lower settings produce smooth and rounded curves:

  • You can see a slight ease-in and ease-out effect.
  • Valid values range between -10.0 and 10.0.
  • The result of your settings is displayed in the graph.
Continuity

This parameter controls the keys tangents:

  • Higher values produce a curved overshoot on both sides of the key.
  • Lower values result in curves similar to high tension, but without any ease-in or ease-out effects.
  • Valid values range between -10.0 and 10.0.
  • Negative values create a sharp change in motion such as that of a falling ball striking a floor and quickly reversing direction.
Bias

A good example is a race car moving around a bend: it could use either a negative or a positive setting to 1) anticipate the turn with a negative bias, or 2) overshoot the turn with a positive bias:

  • Valid values range between -10.0 and 10.0.
  • High values create a (more or less) linear curve before the key and an exaggerated curve behind it. The result is a kind of hump behind the currently active key.
  • Low values show higher curvature before entering the key and a steeper progression leaving the key.
Incoming/Outgoing

These parameters are only visible with "Bezier"-type keys. By default, an animation key uses one interpolation method, but you can apply two methods:

  • “Incoming” applies to the parameter value as the current time approaches a keyframe
  • “Outgoing” applies to the parameter value as the current time leaves a keyframe.

Unlike other interpolation methods, "Bezier" interpolation lets you create any combination of curves and straight lines along the motion path. Because the two "Bezier" direction handles operate independently, a curving motion path can suddenly turn into a sharp corner at a key.