A system for interactive modeling of physical curved surface objects

Abstract

It is often important to obtain descriptions of existing objects for computer graphics data bases. A system to aid interactive modeling (in three dimensions) of a physical object is described. The system allows a user to fit a bi-cubic parametric spline surface to an object by superimposing stereoscopic views of the computer surface with stereoscopic television views of the object. A 3-D joystick is used to manipulate surface control points while the user views the computed surface as isoparametric contours. A raster scan display polarization stereoscope is used. The left eye and right eye surface views are computed using a unique display processor designed and constructed for the evaluation of raster scan graphics techniques. The display processor consists of multiple non-pipelined concurrently operating microprogrammed modules. The computation of the two reasonably complex images (>500 vectors each) takes less than 33 msec allowing real time display at standard television rates.