Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 567

Interpolation methods
For all of the Interpolation methods, the argument
If is , the interpolation between values happens over a duration. If
time
t
range of values to a new range of values.
linear(t, tMin, tMax, value1, value2)
Argument type: t, tMin, and tMax are Numbers, and value1 and value2 are Numbers or Arrays.
Returns value1 when t <= tMin. Returns value2 when t >= tMax. Returns a linear interpolation between value1 and
value2 when tMin < t < tMax.
For example this expression on the Opacity property causes Opacity values to ramp linearly from 20% to 80% over
the time from 0 to 6 seconds:
linear(time, 0, 6, 20, 80)
This method—like all of the Interpolation methods—can also be used to convert from one range of values to another.
For example this expression on the Opacity property converts the Opacity values from the range 0%-100% to the
range 20%-80%:
linear(value, 0, 100, 20, 80)
Return type: Number or Array.
linear(t, value1, value2)
Argument type: t is a Number, and value1 and value2 are Numbers or Arrays.
Returns a value that linearly interpolates from value1 to value2 as t ranges from 0 to 1. Returns value1 when t <= 0.
Returns value2 when t >= 1.
Return type: Number or Array.
ease(t, value1, value2)
Argument type: t is a Number, and value1 and value2 are Numbers or Arrays.
Similar to with the same arguments, except that the interpolation eases in and out so that the velocity is 0 at
linear
the start and end points. This method results in a very smooth animation.
ease(t, tMin, tMax, value1, value2)
Argument type: t, tMin, and tMax are Numbers, and value1 and value2 are Numbers or Arrays.
Similar to with the same arguments, except that the interpolation eases in and out so that the velocity is 0 at
linear
the start and end points. This method results in a very smooth animation.
easeIn(t, value1, value2)
Argument type: t is a Number, and value1 and value2 are Numbers or Arrays.
Similar to , except that the tangent is 0 only on the value1 side and interpolation is linear on the value2 side.
ease
easeIn(t, tMin, tMax, value1, value2)
Argument type: t, tMin, and tMax are Numbers, and value1 and value2 are Numbers or Arrays.
Similar to , except that the tangent is 0 only on the tMin side and interpolation is linear on the tMax side.
ease
easeOut(t, value1, value2)
Argument type: t is a Number, and value1 and value2 are Numbers or Arrays.
Similar to , except that the tangent is 0 only on the value2 side and interpolation is linear on the value1 side.
ease
easeOut(t, tMin, tMax, value1, value2)
t
Return type: Number or Array.
Return type: Number or Array.
Return type: Number or Array.
Return type: Number or Array.
Return type: Number or Array.
Return type: Number or Array.
is often or , though it can have other values, instead.
time value
is
value
t
AFTER EFFECTS CS3
, then the expression maps one
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