Affine maps in 3D are a primary tool for modeling and computer graphics. We show how to build an affine map that maps one tetrahedron to another. A constructive approach to building parallel projections is described. We move past affine maps and introduce homogeneous coordinates and perspective maps—the maps used to create realistic 3D images. An application of building an instance model from a simple prototype object is introduced. This application provides an opportunity to demonstrate the non-commutativity property of affine maps in 3D. Sketches and figures illustrate the concepts.