Browse Prior Art Database

High-Speed Pick Mechanism for 3D Graphics Systems

IP.com Disclosure Number: IPCOM000114779D
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 4 page(s) / 89K

Publishing Venue

IBM

Related People

Kawase, K: AUTHOR [+4]

Abstract

Disclosed is a high-speed pick mechanism for 3D graphics systems. One of the most important facilities in 3D graphics systems is the picking of objects specified by the user on the displayed screen. However, the picking performance in current 3D graphics systems is not satisfactory, especially in Computer-Aided Design (CAD) applications. The disclosed method can improve the picking performance through the use of parallel processing.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

High-Speed Pick Mechanism for 3D Graphics Systems

      Disclosed is a high-speed pick mechanism for 3D graphics
systems.  One of the most important facilities in 3D graphics systems
is the picking of objects specified by the user on the displayed
screen.  However, the picking performance in current 3D graphics
systems is not satisfactory, especially in Computer-Aided Design
(CAD) applications.  The disclosed method can improve the picking
performance through the use of parallel processing.

      The following explanation assumes that the Programmer's
Hierarchical Interactive Graphics System (PHIGS, defined by ISO) is
employed as a 3D graphics application interface.  However, the
disclosed method can be applied to other 3D graphics application
interfaces.

      The Figure shows an example of this method.  The structure
store is used for storing PHIGS structures.  A PHIGS structure
consists of attributes and primitives; these two categories are also
called elements.

      The dispatch processor is a special hardware device that
traverses the PHIGS structures stored in the structure store and
dispatches them to each geometry node per PHIGS primitive basis.  The
geometry node consists of a general micro processor that has a
high-performance floating-operation unit and a memory.  The geometry
node processes the primitive that is sent by the dispatch processor
and checks whether the dispatched primitive hits the aperture
specified by the user in the screen space.  The merge processor
collects the calculation results from each geometry node.

The dispatch processor has following functions:
  o  Traverse the structure store and get a stream of elements.
  o  Select one geometry node and dispatch the primitive to it.
  o  Broadcast the attribute to all geometry nodes.
  o  Count the dispatched elements.

When the dispatch proce...