3

6 Chapter 1 3D Compositing
Coordinates and Object Position in Space
The location of an object in Motion can be described in these terms as well. The
coordinate system used by Motion specifies the center of the Canvas as 0, 0, 0. Moving
an object to the left subtracts from the X value, while moving to the right adds to the X
value. Moving an object up adds to the Y value, and moving an object down subtracts
from the Y value. Moving an object closer adds to the Z value, while moving further
away subtracts from the Z value. The main difference between a 2D scene and a 3D
scene is that in a 3D scene, you can change your point of view, so that moving an
object up doesn’t always mean increasing its Y Position value.
Note: In a new project, the Canvas is oriented with the Z axis pointing straight at you.
This orientation preserves the traditional two-dimensional orientation of the X and Y
axes, which span the default Canvas from left to right (X) and top to bottom (Y).
3D Conventions
There are a few conventions commonly used to discuss and display three-
dimensional environments.
 Object movement is along an axis.
 Object rotation is around an axis.
 Each axis is color-coded: X is red, Y is green, and Z is blue.
 Positive rotation is counterclockwise around an axis.