GRIN: Interactive Graphics for Modeling Solids

This paper describes an experimental system for the original generation and subsequent modification of volume models of complex physical objects, using interactive computer graphics. The models are built up from primitive volumes, e.g., cuboids, cylinders, swept surfaces, etc., entered by a mechanical engineer interacting with a two dimensional projection of the model on a graphic display screen. The primitives may be entered at any orientation in 3-space and combined to form a single polyhedral model. The central issue is the provision of an efficient, natural means for generating these models.