Browse Prior Art Database

Anticipatory Calculation of Two-Dimensional Views of a Multi- Dimensional Object

IP.com Disclosure Number: IPCOM000122155D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 4 page(s) / 147K

Publishing Venue

IBM

Related People

Collins, BM: AUTHOR

Abstract

A method of graphical calculation is disclosed that reduces the response time and improves the user interface for the generation of two-dimensional bit-mapped images from multi-dimensional objects when a change of a user's viewpoint occurs. It relates to UKSC graphics work on the Winchester Solid Modeller System (WINSOM): in particular to CARVUPP, WINSOM, WINSOM90 and WINVIS90 prototypes and their derivatives. It could also relate to other Data and Volume Visualization software.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 44% of the total text.

Anticipatory Calculation of Two-Dimensional Views of a Multi- Dimensional
Object

      A method of graphical calculation is disclosed that
reduces the response time and improves the user interface for the
generation of two-dimensional bit-mapped images from
multi-dimensional objects when a change of a user's viewpoint occurs.
It relates to UKSC graphics work on the Winchester Solid Modeller
System (WINSOM): in particular to CARVUPP, WINSOM, WINSOM90 and
WINVIS90 prototypes and their derivatives.  It could also relate to
other Data and Volume Visualization software.

      This method is applicable to objects in more than three
dimensions, e.g., three spatial, one temporal and one frequency, but
the following description will use 3-dimensional spatial objects for
simplicity.  A 3-dimensional solid object is displayed on a computer
graphics raster as a 2-dimensional bit-mapped image.  The user is
assumed to be at a viewpoint, and the 2-dimensional image is formed
by the projection of the 3-D object onto a viewing plane, as in Fig.
1.  The 2-dimensional image is rendered by software, such as WINSOM
or CARVUPP, and techniques, such as hidden surface removal, lighting
and shading, are used to give the image a 3-dimensional appearance.
The calculation of this image can be achieved solely by software, or
utilizing some specialized graphics hardware, or both.

      When a user wishes to transform a 3-dimensional object, i.e.,
change his or her viewpoint with respect to the object, such as a
rotation or translation or scaling, the 2-dimensional image has to be
recalculated.  The traditional sequency of events is then:
      Step 1  -  User defines a viewpoint
      Step 2  -  Calculation of 2-dimensional image
      Step 3  -  Display of 2-dimensional image
      Step 4  -  User looks at image
      .    .    .    .
      .    .    .    .
      .    .    .    .
      User ends session

      Steps 1 to 4 are repeated for each viewpoint until the user
interaction with the object ends.  Only during Steps like 2 are
intensive calculations being performed, so Steps 1, 3 and 4 contain
"unused cycles" which could be used for calculations, but typically
are not.

      Disclosed is the use of these "unused cycles" to calculate the
2-dimensional views that a user might define at some time in the
session, or to "anticipate" those views, and to allow the user to
influence the anticipated viewpoints by an optional user interface.

      Thus, the anticipatory calculations are those performed in
Steps like 2 above, but, for a sequence of "yet-to-be-chosen"
viewpoints, they are actually performed in Steps like 1, 3 and 4.
When the user does define a new viewpoint, if a 2-dimensional image
has already been calculated (anticipated), then it can be displayed
immediately, removing the time required for Steps like 2 from the
usual sequence of events, and significa...