2924	 An Interactive Computer Graphics Approach to Surface Representation	 An in teractive computer graphics method has been developed for the rapid generation of arbitrary shaped three-dimensional surfaces. The method is a synthesis of spline theory and algorithms an in teractive means for man-machine communication and software for static or dynamic graphics display. The basic technique employed is a modified lofting method on which sectional curves are represented by uniform B-splines and the surface is in terpolated between sections by Cardinal splines. Among the features of this method are algorithms which enable in teractive modification of the B-spline representation of the sectional curves. At all stages of the process the spatial information is graphically displayed to the user. Complex surfaces can be created by the combination of a number of shapes that have been separately generated and automatically joined. The system has been successfully in terfaced to a variety of analytical routines for structural medical and graphical applications. computer graphics three-dimensional surface representation splines lofting finite element input methods
