The design process is a series of decisions made in a sequential way to achieve desired goal and objective. Three-dimensional (3-D) models are essential to the creative process, aiding in decision-making necessary to advance a design. This chapter provides a broad overview of the different types most relevant to transportation and vehicle design. It discusses deployment strategies for different types of model-making. Alias Studio Tools is a common software package used by designers and modelers in automotive and transportation design industry. It generates surfaces using non-uniform rational basis splines (NURBS) surface construction, based on mathematical splines and curves, and is in fact an outgrowth of traditional analog vehicle modeling techniques. Many designers can use programs such as Alias quite early on in the process to rough out ideas and verify that they work over a given package. This process is referred to as sketch modeling, meaning it blends rapid visualization sketching which can provide with three-dimensional verification that modeling ensures.