Adobe 65008009 - After Effects CS4 Using Manual page 151

Last updated 12/21/2009
Coordinate systems: composition space and layer space
The coordinate system for each layer is its layer space. The coordinate system for each composition is its composition
space. Property values for items that exist within a layer—such as effect control points and anchor points—exist in layer
space and are measured from the origin in the layer space of that layer. The Position property of a layer, however,
describes where the layer is within a composition and is therefore measured in the composition space of that
composition.
As you move the pointer over the layer frame in the Layer panel, the Info panel displays the coordinates of the pixel
under the pointer in layer space. The X coordinate represents position on the horizontal axis, and the Y coordinate
represents position on the vertical axis. Values for these coordinates are in pixels. The X and Y coordinates are relative
to the origin (0,0), which is fixed at the upper left corner of the layer.
You can modify the zero point of the rulers, but you can't modify the origin of layer space. If the zero point differs from
the origin, X' and Y' coordinates appear in the Info panel below the X and Y coordinates, indicating coordinates based
on the zero point of the rulers.
When you move the pointer over the composition frame in the Composition panel, the Info panel displays coordinates
in composition space. As you drag a layer, the lower portion of the Info panel displays the coordinates of the anchor
point of the layer.
More Help topics
"Safe zones, grids, guides, and
"Layer anchor points" on page 162
Move layers in space
When you move a layer in space, you modify its Position property.
You can separate the components of a Position property into individual properties—X Position, Y Position, and (for
3D layers) Z Position—so that you can modify or animate each independently. (See
to animate components individually" on page 146.)
Jeff Almasol provides a script on his
points of two selected layers; you use a slider control on the null layer to reposition the null layer along this line.
To move selected layers so that their anchor points are at the center in the current view, choose Layer > Transform >
Center In View or press Ctrl+Home (Windows) or Command+Home (Mac OS).
To move a layer so that its anchor point is at the center of the composition, right-click (Windows) or Control-click
(Mac OS) the Position property, choose Edit Value, choose % Of Composition in the Units menu, and enter 50 for each
of the components of the Position property.
To avoid softening of an image that is not moving, make sure that a layer's Position values are non-fractional values.
This avoids resampling that is used when a layer with image quality set to Best is placed on subpixels.
More Help topics
"Safe zones, grids, guides, and
"Layer anchor points" on page 162
"Select layers" on page 143
"Layer properties" on page 159
rulers" on page 207
redefinery website that places a new null layer on the line between the anchor
rulers" on page 207
USING AFTER EFFECTS CS4
Layers and properties
"Separate dimensions of Position
145