interpolation
Interpolation
Section titled “Interpolation”For all the Interpolation methods, the argument t is often time or value, though it can have other values, instead. If t is time, the interpolation between values happens over a duration. If t is value, then the expression maps one range of values to a new range of values.
All the Interpolation methods can also be used to convert from one range of values to another.
Chris and Trish Meyer provide additional information and examples for these methods in an article on the ProVideo Coalition website.
Ian Haigh provides a script on After Effects Scripts website that you can use to easily apply advanced interpolation method expressions—such as bounces—to properties.
Methods
Section titled “Methods”linear(t, tMin, tMax, value1, value2)
Section titled “linear(t, tMin, tMax, value1, value2)”linear(t, tMin, tMax, value1, value2)
Description
Section titled “Description”Returns value1 when t <= tMin. Returns value2 when t >= tMax. Returns a linear interpolation between value1 and value2 when tMin < t < tMax.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
tMin | Number | Minimum driver value |
tMax | Number | Maximum driver value |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
Example
Section titled “Example”This expression on the Opacity property causes Opacity values to ramp linearly from 20% to 80% over the time from 0 seconds to 6 seconds:
linear(time, 0, 6, 20, 80)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)linear(t, value1, value2)
Section titled “linear(t, value1, value2)”linear(t, value1, value2)
Description
Section titled “Description”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.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
ease(t, tMin, tMax, value1, value2)
Section titled “ease(t, tMin, tMax, value1, value2)”ease(t, tMin, tMax, value1, value2)
Description
Section titled “Description”Similar to linear with the same arguments, except that the interpolation eases in and out so that the velocity is 0 at the start and end points. This method results in a smooth animation.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
tMin | Number | Minimum driver value |
tMax | Number | Maximum driver value |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
ease(t, value1, value2)
Section titled “ease(t, value1, value2)”ease(t, value1, value2)
Description
Section titled “Description”Similar to linear with the same arguments, except that the interpolation eases in and out so that the velocity is 0 at the start and end points. This method results in a smooth animation.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
easeIn(t, tMin, tMax, value1, value2)
Section titled “easeIn(t, tMin, tMax, value1, value2)”easeIn(t, tMin, tMax, value1, value2)
Description
Section titled “Description”Similar to ease, except that the tangent is 0 only on the tMin side and interpolation is linear on the tMax side.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
tMin | Number | Minimum driver value |
tMax | Number | Maximum driver value |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
easeIn(t, value1, value2)
Section titled “easeIn(t, value1, value2)”easeIn(t, value1, value2)
Description
Section titled “Description”Similar to ease, except that the tangent is 0 only on the value1 side and interpolation is linear on the value2 side.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
easeOut(t, tMin, tMax, value1, value2)
Section titled “easeOut(t, tMin, tMax, value1, value2)”easeOut(t, tMin, tMax, value1, value2)
Description
Section titled “Description”Similar to ease, except that the tangent is 0 only on the tMax side and interpolation is linear on the tMin side.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
tMin | Number | Minimum driver value |
tMax | Number | Maximum driver value |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array
easeOut(t, value1, value2)
Section titled “easeOut(t, value1, value2)”easeOut(t, value1, value2)
Description
Section titled “Description”Similar to ease, except that the tangent is 0 only on the value2 side and interpolation is linear on the value1 side.
Parameters
Section titled “Parameters”| Parameter | Type | Description |
|---|---|---|
t | Number | Interpolation Driver |
value1 | Number or Array | Value to interpolate from |
value2 | Number or Array | Value to interpolate to |
Returns
Section titled “Returns”Number or Array