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.RP
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UNDERSTANDING
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THE PREPARATION AND ANALYSIS OF
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SOLID MODELS
.AU
Michael John Muuss
.AI
Leader, Advanced Computer Systems Team
U. S. Army Ballistic Research Laboratory
Aberdeen Proving Ground
Maryland 21005-5066 USA
.AB
.LP
The origins and basic principles of solid modeling
will be reviewed.
Topics to be covered include a detailed look at the
primitive solids and their mathematical descriptions, a review of
boolean mathematics for solids combination, and the use of homogeneous
coordinates for object positioning.
References to various existing solid
modeling systems will be given.
.LP
As a case study of a modern solid modeling system,
the U. S. Army Ballistic Research
Laboratory's (BRL) solid modeling system will be described.
In addition to an
overview of the constructive solid modeling based geometric design
editor's (MGED) features and operations, examples of constructing objects
using MGED will be presented.
MGED's capabilities, command interface,
code organization and internal editing states will be discussed.
Important considerations in preparing and organizing large models
will be presented.
.LP
A detailed investigation of the algorithms needed to
ray-trace a solids model will be presented.
The mathematics of ray-solid
intersection will be shown for three primitive solids.
Bounding
volumes will be discussed, along with boolean expression tree evaluation.
The general data structures, code organization, and space partitioning
algorithms of BRL's ray tracing package (RT) will be reviewed, and a sample
application will be given.
.LP
An overview of how ray-tracing of solids
models can be applied to compute information about the
properties of the structure being modeled will be given.
Image rendering, property calculations, and
specific engineering assessments will be examined.
.AE
.RT
