Designing surfaces in 3-D

An experimental system for computer-aided design of free-form surfaces in three dimensions is described. The surfaces are represented in the system as parametric basis splines. The principal features of the system are: (1) the surfaces are rendered as isoparametric line drawings on a head-mounted display, and they are designed with the aid of a three-dimensional “wand,” which allows 3-D movements of the points controlling the shapes of the surfaces, (2) all of the interactions with the surfaces are in real-time, and (3) the mathematical formulations used assume no knowledge of them by the user of the system. Also examined are some of the features that should be part of a practical 3-D system for designing space-forms.