For millennia the horse was the primary mode of transportation for mounted soldiers. Ingress and egress from a horse’s back is straightforward, space claims are only related to the size of the saddle, and there were no confining walls to restrict what soldiers carried while on horseback. With the rise of the modern mechanized army, vehicle design became more complex. Critical to the effective design of vehicle interiors is an accurate model of the encumbered operator or passenger. Developments in three-dimensional (3d) scanning, computer-aided design (CAD) and other model creation capabilities make it possible to reproduce accurately the underlying human form and to add equipment encumbrances. This paper relates approaches taken in studies where Soldiers or aviators were modeled to define space requirements or reaches. Details of the modeling process, validation, and study results are given. Future research is discussed.