Object Space and World Space

Fastgraph's 3D geometry system uses two separate but related 3D coordinate systems: object space and world space.

Object space, also called model space in some 3D references, is the coordinate system in which a specific 3D object is defined. Usually, but not always, each object will have its own distinct object space with the origin at the object's center. By center, we mean the point about which the object is moved and rotated, which is not necessarily the object's geometric center.

World space is the coordinate system of our 3D universe. Stationary objects such as walls are well-suited for world space, but as we'll see, moving objects are best defined in object space. We also use world space coordinates to define the position and orientation of the viewer within our 3D universe, which is called the point of view or POV. By default, the POV is at the world space origin, looking straight down the positive z axis.