Multiple Coordinate Spaces
Fletcher Dunn, Ian Parberry · 2011
This chapter provides some examples of common coordinate spaces that are used for graphics and games. It discusses how coordinate spaces are nested within other coordinate spaces. The chapter introduces the idea of multiple coordinate systems and describes coordinate-space transformations. It also discusses nested coordinate spaces, commonly used for animating hierarchically segmented objects in three dimensions (3D) space. An object’s upright space is, in a certain sense, “halfway” between world space and its object space. The axes of upright space are parallel with the axes of world space, but the origin of upright space is coincident with the origin of object space. One especially important example of an object space is camera space, which is the object space associated with the viewpoint used for rendering. Note carefully the differences between camera space, which is a 3D space, and screen space, which is a two dimensions space.