Abstract: A computer graphics system is disclosed. The system is for modeling parametric objects having segments of an intersection of a modular matrix of rectangles and an elliptic, lenticular or rhombic segment. The system includes a retrieval and display function for an object which include segments of an intersection of a modular matrix of rectangles and an elliptic, lenticular or rhombic segment. The resulting intersection segments have boundary surfaces that intersect at vertices and which have a common origin. The system includes a calculation of the location of the vertices relative to the common origin and evaluates and discards invalid vertices. The system also calculates the boundary surfaces of intersection segments, defined by valid vertices. Output is provided in the form of geometrically accurate and undistorted digital models.

Abstract: A computer graphics system is disclosed. The system is for modelling parametric objects having elliptical segments, which are defined as segments bounded by linear radial and elliptical tangential elements. The system includes a retrieval and display function for an object having elliptical segments which have boundary surfaces that intersect at vertices and which have a common origin. The system includes a calculation of the location of the vertices relative to the common origin and evaluates and discards invalid vertices. The system also calculates the boundary surfaces of individual elliptical segments, defined by valid vertices. Output is provided in the form of dimensionally accurate and geometrically undistorted digital models. In one embodiment the system is useful in designing elliptical elements for doors, windows and the like in an architectural drafting program.