Motion 5 - Modifying Curves

Modifying Curves

The Keyframe Editor lets you make changes to the curves between keyframes. This might
be the Keyframe Editor’s most valuable feature. Although you can manually create nearly
any curve shape to create the animation you want, Motion also provides tools to control
the automatic interpolation and extrapolation of parameter values.

To set the interpolation for a curve, you select the keyframe you want to modify. The
method you choose determines the distribution of values through, into, or out of the
selected keyframe. By using different preset mathematical algorithms, you can dramatically
alter the impact of your effects.

To set an interpolation method for a keyframe

µ

Control-click a keyframe, choose Interpolation from the shortcut menu, then choose a
method from the submenu.

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Select multiple keyframes, Control-click one of them, choose Interpolation from the
shortcut menu, then choose a method from the submenu.

The interpolation method chosen is applied to the entire selection.

To set an interpolation method on a curve segment

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Control-click a segment between two keyframes, choose Interpolation from the shortcut
menu, then choose a method from the submenu.

Only the segment between the surrounding two keyframes is affected by the interpolation
method you choose. You can set different interpolation methods for other segments of
the same curve.

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When different interpolation methods are applied to segments of an animation curve,
the methods used in the curve appear with a dash next to their name in the Interpolation
submenu (in the Keyframe Editor parameter list).

Interpolation methods include the following:

• Constant: This method holds the keyframe at its current value when applied to a

segment or keyframe and then abruptly changes to the new value at the next keyframe.

• Linear: When applied to a keyframe, this method creates a uniform distribution of

values through the keyframe from its two adjacent keyframes. When applied to a
segment, this method creates uniform distribution of values between points.

• Bezier: This method lets you manipulate the keyframe curve manually by dragging the

handles. If multiple Bezier keyframes are selected, or Bezier interpolation is applied to
the curve segment, the handles of all selected keyframes are modified.

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• Continuous: This method behaves like Bezier interpolation, but without access to the

handles (which are calculated automatically). The parameter begins to change gradually,
reaching its maximum rate of acceleration at the midpoint, then tapers off slightly as
it approaches the second keyframe. When applied to a keyframe, the segments before
and after the keyframe are affected. When applied to a curve segment, the segment
between the keyframes is affected.

• Exponential: This method creates an exponential curve between the current keyframe

and the next, changing the value slowly at first, then reaching its maximum rate of
acceleration as it approaches the next keyframe.

• Logarithmic: This method creates a logarithmic curve between the current keyframe

and the next, changing the value rapidly at first, then slowing drastically as it approaches
the next keyframe.

• Ease In: This method has a reverse-inertia effect, so a value change slows coming into

a keyframe. When applied to a curve segment, the value change eases into the segment.
This option is available only when you Control-click a keyframe; it is not available in
the Animation pop-up menu.

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• Ease Out: This method creates a typical inertia-like lag, so a value change begins more

slowly coming out of a keyframe. When applied to a curve segment, the value change
eases out of the segment. This option is available only when you Control-click a
keyframe; it is not available in the Animation pop-up menu.

• Ease Both: This method combines Ease In with Ease Out, applying both at once. This

option is available only when you Control-click a keyframe; it is not available in the
Animation pop-up menu.

Alternatively, you can apply an interpolation method to the entire parameter.

To change the interpolation method for an entire parameter

µ

Click in the fifth column of the Keyframe Editor parameter list to open the Animation
menu, then choose a method from the Interpolation submenu.

The selected interpolation method is applied to that parameter’s curve.

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