Constructive Cubes: CSG Evaluation For Display Using Discrete 3-D Scalar Data Sets

127 The algorithm presented in this paper converts a CSG model into a representation for in­ teractive display on an engineering workstation. Called Constructive Cubes, the algorithm extends the standard CSG-point classification algorithm and then employs a popular iso­ surface generation algorithm, Marching Cubes, to generate a list of polygons that approxi­ mates the surface of a CSG model. The polygons may then be interactively displayed, shaded and inspected on a workstation. The algorithm has many advantages over other CSG algorithms. It is straightforward to implement, requiring no complex surface intersec­ tion calculations. The algorithm provides an inherent flexibility that allows a user to bal­ ance the time/quality trade-off. It is designed to take advantage of current and future ad­ vances in both visualization and engineering workstation design.