The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 25, 1991
Filed:
Apr. 19, 1989
Jaroslaw R Rossignac, Ossining, NY (US);
David A Epstein, New York, NY (US);
Nader Gharachorloo, Ossining, NY (US);
Frederik W Jansen, North Tarrytown, NY (US);
Christos S Zoulas, Ithaca, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
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.