Layer Space Transforms methods (expression reference)

Use layer space transform methods to transform values from one space to another, such as from layer space to world space. The “from” methods transform values from layer space to the named space (composition or world). The “to” methods transform values from the named space (composition or world) to layer space. Each transform method takes an optional argument to determine the time at which the transform is computed; however, you can almost always use the current (default) time.

Use “Vec” transform methods when transforming a direction vector, such as the difference between two position values. Use the plain (non-”Vec”) transform methods when transforming a point, such as position. Composition (comp) and world space are the same for 2D layers. For 3D layers, however, composition space is relative to the active camera, and world space is independent of the camera.

toComp(point, t=time)
Return type: Array [2 or 3].

Argument type: point is an Array [2 or 3], and t is a Number.

Transforms a point from layer space to composition space.

fromComp(point, t=time)
Return type: Array [2 or 3].

Argument type: point is an Array [2 or 3], and t is a Number.

Transforms a point from composition space to layer space. The resulting point in a 3D layer may have a nonzero value even though it is in layer space. Example: fromComp(thisComp.layer(2).position)

toWorld(point, t=time)
Return type: Array [2 or 3].

Argument type: point is an Array [2 or 3], and t is a Number.

Transforms a point from layer space to view-independent world space. Example:

`  toWorld.effect("Bulge")("Bulge Center")`

Dan Ebberts provides an expression on his MotionScript website that uses the toWorld method to auto-orient a layer along only one axis. This is useful, for example, for having characters turn from side to side to follow the camera while remaining upright.

Carl Larsen provides a pair of video tutorials on the Creative COW website in which he explains the basics of parenting and then uses an expression involving the toWorld method to trace the path of an animated child layer:

fromWorld(point, t=time)
Return type: Array [2 or 3].

Argument type: point is an Array [2 or 3], and t is a Number.

Transforms a point from world space to layer space. Example: fromWorld(thisComp.layer(2).position)

See Expression example: Create a bulge between two layers for an example of how this method can be used.

toCompVec(vec, t=time)
Return type: Array [2 or 3].

Argument type: vec is an Array [2 or 3], and t is a Number.

Transforms a vector from layer space to composition space. Example: toCompVec([1,0])

fromCompVec(vec, t=time)
Return type: Array [2 or 3].

Argument type: vec is an Array [2 or 3], and t is a Number.

Transforms a vector from composition space to layer space. Example (2D layer):

```  dir=sub(position, thisComp.layer(2).position);
fromCompVec(dir)```

toWorldVec(vec, t=time)
Return type: Array [2 or 3].

Argument type: vec is an Array [2 or 3], and t is a Number.

Transforms a vector from layer space to world space. Example:
```  p1 = effect("Eye Bulge 1")("Bulge Center");
p2 = effect("Eye Bulge 2")("Bulge Center");
toWorld(sub(p1, p2))```

fromWorldVec(vec, t=time)
Return type: Array [2 or 3].

Argument type: vec is an Array [2 or 3], and t is a Number.

Transforms a vector from world space to layer space. Example: fromWorld(thisComp.layer(2).position)

fromCompToSurface(point, t=time)
Return type: Array [2].

Argument type: point is an Array [2 or 3], and t is a Number.

Projects a point located in composition space to a point on the surface of the layer (zero z-value) at the location where it appears when viewed from the active camera. This method is useful for setting effect control points. Use with 3D layers only.