Vector Math

Vector Math functions are global methods that perform operations on arrays, treating them as mathematical vectors. Unlike built-in JavaScript methods, such as Math.sin, these methods are not used with the Math prefix. Unless otherwise specified, Vector Math methods are lenient about dimensions and return a value that is the dimension of the largest input Array object, filling in missing elements with zeros.

For example, the expression add([10, 20], [1, 2, 3]) returns [11, 22, 3].

Note

JJ Gifford’s website provides explanations and examples that show how to use simple geometry and trigonometry with expressions.


add(vec1, vec2)

Description

Adds two vectors.

Parameters

vec1 Array
vec2 Array

Type

Array


sub(vec1, vec2)

Description

Subtracts two vectors.

Parameters

vec1 Array
vec2 Array

Type

Array


mul(vec, amount)

Description

Multiplies every element of the vector by the amount.

Parameters

vec Array
amount Number

Type

Array


div(vec, amount)

Description

Divides every element of the vector by the amount.

Parameters

vec Array
amount Number

Type

Array


clamp(value, limit1, limit2)

Description

The value of each component of value is constrained to fall between the values of the corresponding values of limit1 and limit2.

Parameters

value Number or Array
limit1 Number or Array
limit2 Number or Array

Type

Number or Array


dot(vec1, vec2)

Description

Returns the dot (inner) product of the vector arguments.

Parameters

vec1 Array
vec2 Array

Type

Number


cross(vec1, vec2)

Description

Returns the vector cross product of vec1 and vec2. Refer to a math reference or JavaScript guide for more information.

Parameters

vec1 Array (2- or 3-dimensional)
vec2 Array (2- or 3-dimensional)

Type

Array (2- or 3-dimensional)


normalize(vec)

Description

Normalizes the vector so that its length is 1.0. Using the normalize method is a short way of performing the operation div(vec, length(vec)).

Parameters

vec Array

Type

Array


length(vec)

Description

Returns the length of vector vec.

Parameters

vec Array

Type

Number


length(point1, point2)

Description

Returns the distance between two points. The point2 argument is optional.

For example, length(point1, point2) is the same as length(sub(point1, point2)).

For example, add this expression to the Focus Distance property of a camera to lock the focal plane to the camera’s point of interest so that the point of interest is in focus:

length(position, pointOfInterest)

Parameters

point1 Array
point2 Array

Type

Number


lookAt(fromPoint, atPoint)

Description

The argument fromPoint is the location in world space of the layer you want to orient. The argument atPoint is the point in world space you want to point the layer at. The return value can be used as an expression for the Orientation property, making the z-axis of the layer point at atPoint.

This method is especially useful for cameras and lights. If you use this expression on a camera, turn off auto-orientation.

For example, this expression on the Orientation property of a spot light makes the light point at the anchor point of layer number 1 in the same composition:

lookAt(position, thisComp.layer(1).position)

Parameters

fromPoint Array (3-dimensional)
atPoint Array (3-dimensional)

Type

Array (3-dimensional)