International Business Machines Corporation

Nader Gharachorloo

Christos S. Zoulas

David A. Epstein

Jaroslaw R. Rossignac

Frederik W. Jansen

Frederik W Jansen

David Alexander Epstein

Jaroslaw R Rossignac

Christos S Zoulas

David A Epstein

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.

Multiple depth buffers for graphics and solid modelling

Growing community of inventors

North Tarrytown, NY, United States of America

Frederik W Jansen