公开(公告)号：US5027292A

公开(公告)日：1991-06-25

申请号：US340322

申请日：1989-04-19

申请人： Jaroslaw R. Rossignac ,  David A. Epstein ,  Nader Gharachorloo ,  Frederik W. Jansen ,  Christos S. Zoulas

发明人： Jaroslaw R. Rossignac ,  David A. Epstein ,  Nader Gharachorloo ,  Frederik W. Jansen ,  Christos S. Zoulas

IPC分类号： G06T15/40

CPC分类号： G06T15/405

摘要： A CSG solid modelling system 10 has a triple z-buffer architecture. For each pixel stored in a pixel memory 12 there are five storage entries grouped into five buffers including a front z-buffer (F) 16 which is employed to store the depths of a front face for a currently processed z-connected product, a back z-buffer (B) 18 which is employed to store the depths of a back face for the currently processed z-connected product and a final z-buffer (Z) 20 which stores the front faces of a displayed solid. Two other buffers are an intensity buffer (T) 22 for storing the intensities associated with the front face of the current z-connected product and a final intensity buffer (I) 24 for storing the intensities of the visible faces of the displayed solid. A bus 26 couples these various buffers together and to a processor 28 which may be a central processing unit or a peripheral processor. The system provides for a solid represented by any CSG tree to be represented as a union of z-connected products and that these z-connected products be expressed as intersections of z-connected sweeps. Furthermore it is shown that expressions of z-connected products in terms of sweeps are extracted directly from a CSG tree. Variations of the display methods may be used to detect interferences and differences between solids defined in CSG.