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Citation |
- Permanent Link:
- http://digital.auraria.edu/AA00004431/00001
Material Information
- Title:
- A study of two-dimensional line drawing translation to three-dimensional data
- Creator:
- Kato, Makoto
- Publication Date:
- 1990
- Language:
- English
- Physical Description:
- 1 volume (various pagings) : illustrations ; 28 cm
Subjects
- Subjects / Keywords:
- Computer-aided design ( lcsh )
Computer graphics ( lcsh ) Three-dimensional display systems ( lcsh ) Computer-aided design ( fast ) Computer graphics ( fast ) Three-dimensional display systems ( fast )
- Genre:
- bibliography ( marcgt )
theses ( marcgt ) non-fiction ( marcgt )
Notes
- Bibliography:
- Includes bibliographical references.
- General Note:
- Submitted in partial fulfillment of the requirements for thesis research and programming, Master of Architecture, College of Architecture and Planning.
- General Note:
- "Post-professional program."
- Statement of Responsibility:
- by Makoto Kato.
Record Information
- Source Institution:
- University of Colorado Denver
- Holding Location:
- Auraria Library
- Rights Management:
- All applicable rights reserved by the source institution and holding location.
- Resource Identifier:
- 24461694 ( OCLC )
ocm24461694
- Classification:
- LD1190.A72 1990 .K372 ( lcc )
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Full Text |
A STUDY OF
TWO-DIMENSIONAL LINE DRAWING
TRANSLATION TO
THREE-DIMENSIONAL DATA
BY MAKOTO KATO
A THESIS SUBMITTED IN FULFILLMENT OF THE REQUIREMENTS
FOR THESIS RESEARCH AND PROGRAMMING
DEGREE OF MASTER OF ARCHITECTURE
IN POST PROFESSIONAL PROGRAM
SCHOOL OF ARCHITECTURE AND PLANNING
UNIVERSITY OF COLORADO AT DENVER
SPRING, 1990
THESIS TITLE
BY
ADVISER
ACADEMIC YEAR
A Study of Two-Dimensional Line Drawing
Translation to Three-Dimensional Data
Makoto Kato
Prof. Robert W. Kindig
Prof. Soontom Boonyatikan
Spring, 1990
Accepted by School of Architecture and Planning, University
of Colorado at Denver in partial fulfillment of the requirements for Thesis
Research and Planning.
.......................... Chairman
(Prof. Won Jin Tae)
Committee Members
(Prof. Soontom Boonyatikan)
(Prof. Robert W. Kindig)
CONTENTS
ABSTRACT 1
INTRODUCTION
PURPOSE 2
FUTURE EXPECTATION OF THIS PROGRAM 3
PARTl:CAAD-Computer Aided Architectural Design
BACKGROUND 6
COMPUTER IN ARCHITECTURAL DESIGN 7
......THE SURVEY OF ARCHITECTURAL DESIGN 8
------ARTIFICIAL INTELLIGENCE IN ARCHITECTURE 10
------CAD SYSTEM ENVIRONMENT 11
3D GRAPHICS SYSTEM AS AN ARCHITECTUAL TOOL 13
PART2: INTERPRETATION OF LINE DRAWING BY COMPUTER
INTERPRETATION METHOD 15
LINE DRAWING CLASSIFICATION 16
PROCEDURE 19
------PRIDM 21
------PYRAMID 22
------POLYHEDRA 23
PART3: PROGRAM
SOURCE AND RESOURCE FOR PROGRAMMING 25
THE ORGANIZATION OF THIS PROGRAM
......FILE DESCRIPTIONS 25
------DATA STRUCTURE 26
------MAINFRAME 27
EXPLANATION OF EACH PROCEDURE 2 8
------DRAWING 29
------INTERPRET 33
------INSPECTION 34
------PRISM 37
------POLY 45
EXECUTION OF PROGRAM 5 7
POTENTIAL OF THIS PROGRAM 63
APPENDIX: 6 4
PROGRAM LIST
REFERENCE LIST
ABSTRACT:
As the capability of the computer is progressing, the CAD system is
getting closer to the architectural work. There are many kinds of software for
CAD systems, and some of them are equipped 3D modeling feature.
However, as a matter of fact, most CAD systems have been utilized just as
rendering tools for presentation, that is, few kinds of software are available
for the actual design process. The computer has been known for dealing with
a large amount of calculation in a short time, namely, it has significant
capability of numerical tasks. Meanwhile, in another field, the computer and
the software are becoming more sophisticated tool which perform non-
numerical tasks such as thinking jobs.
As the computer developed, graphics became one of the most
important aspects in the function of the computer. The graphics are
represented on the screen by transacting the coordinates, on the contrary, the
computer never reacts unless the user inputs numerical factors. As long as
the coordinates is maintained in the memory of the computer, representing
3D objects on the plane monitor screen is not very difficult, today. The
difficulty stems from the method of inputting or developing 3D coordinates.
On the screen, the drawing is merely a collection of lines or a collection of
2D coordinates to the computer even if the drawing is a 3D object, because
the computer monitor represents 2D plane; that is X & Y, and the computer
doesn't have any thought or imagination which human does. This is the
radical reason that the user should assign many commands during operation
even for drawing lines in order to make the computer develop the 3D
coordinates. In today's computer graphics system, these commands are
substituting for the way of human thinking, and it is obvious that the weak
point of the system can be ascribed to a large number of commands.
The CAD system is a tool and won't replace architects. However, the
potential of the computer is unpredictable, and it will support architects with
not only drafting but also thinking tasks such as designing. Hereafter, the
CAD system has to aim to be more a sophisticated tool which has less
number of commands, and which can be used by the architect easily and
frequently. And more flexible three dimensional interface which can treat
abstract objects, such as sketches, will be required for future CAD system to
be utilized in not only the rendering process but also the actual design
process.
INTRODUCTION:
PURPOSE:
The aim of this research is to evolve a method of translation of a line
drawing of a solid on a plane to a three dimensional coordinates. This
research is giving importance to abstract drawings, which has no exact
dimensions such as sketch, rather than precise draftings. The reason is that
today's CAD systems are very powerful as a drafting tools, however, there
are quite a few CAD systems which are effective to the actual design
process. Because, in the actual design process, abstract line drawings of
three dimensional objects are very important for designers to focus their
attentions on the spatial volume and the form, and present CAD system are
not equipped with such a flexible interpretational algorithm.
During the past twenty years, the background of this research has
been developed in both architecture field and engineering field. In
engineering field, the CAD system received great attention even if the
capacity of the computer was not strong enough, or even if the good system
was expensive because of mass production system. However, In architecture
field, the system was not so capable tool because one planning is available
for only one project in most cases, and it was too expensive and too weak to
utilize for each project, so that some theories and algorithm, which were
researched in the past, couldn't get attention and couldn't achieve success.
Particularly, the computational speed of representation of 3D objects was too
slow to use. But last ten years, the capacity of the computer was developed
significantly, and some systems or programs became useful even for the 3D
graphics. At present, the computer is still developing rapidly. The super
computer will be a kind of integrated expert system, and the personal
computer will also have a great capability which only the super computer
has, today. Therefore, more sophisticated algorithm will be able to be
adopted to the future CAD system.
Some of algorithm in this research, which we can not find in
conventional CAD systems, are based on the human interpretation of line
drawing because some of the line drawings can not be interpreted
mathematically. Adding some human interpretation makes the computer
interpret the line drawing of solid on the plane screen as a three dimensional
solid easier, and developing this kind of algorithm will make the use draw
3D objects like a sketching on the paper without assigning many commands.
Practically, this is one of the inevitable research to advance the CAD system
drastically, and to transform today's CAD system to a real architectural tool.
This is one of the primitive program, which is equipped with those
new algorithm. This program differ from the conventional 3D CAD system
in terms of interrupting a 2D drawing as a 3D object. After drawing an object
on a screen, this program interprets a direction of each surface and create 3D
data (coordinates) of not only visible surfaces but also hidden surfaces
automatically. Eventually, this algorithm reduces the amount of annoying
command works of present system; therefore, this can be utilized in many
ways to upgrade the CAD system. In addition, being accompanied with free
hand drawing recognition algorithm, which interpret lines, curves, comers,
etc, the system will be really powerful, in other words, will be easy tool to
use.
FUTURE EXPECTATION OF THIS PROGRAM:
The algorithm of interpretation of 2D line drawings as 3D solids is
inevitable to be the true integrated 3D CAD system. In this research, only the
method of translation from a 2D drawing to 3D coordinates data was
concerned. The reason is that the method of interpreting drawings has some
patterns in theory, and by formulating those method, drawings can be
interpreted. However, another things such as the interpretation of the free
hand drawings doesn't have any theory because those drawings are
interpreted by human experience in most cases. Those kind of research are
classified in AI (Artificial Intelligence) field which deals with human
experiences. If a drawing is clear enough, that can be interpreted by this
algorithm, but if not, the help of AI will be required. At present, still AI is
under development, so that continuing this research is important as well.
If the computer interprets the relation of lines, drawing on the
computer could be easier, and modification of lines will be done without any
command automatically. Therefore, when the algorithm of this program is
connected to the free hand drawing recognition algorithm, the system will
more powerful and more convenient. Users will be able to draw objects
without any command, so that they can concentrate on designing.
Not only algorithms or programs, but the computer environment will
be developed. Particularly, the input device and the monitor screen are
crucial things for the architectural CAD system because those are substituting
pencil and paper. At present, MOUSE and DIGITIZER are the most popular
input devices, but those are much different from conventional drawing tools.
As a monitor device, there is no special device at present, and too difficult to
understand large drawings because of the small screen. In near future, new
monitor device should be concerned, and if one screen is not enough for
architectural work, more than two screens should be recommended as well.
IMAGE OF NEAR FUTURE CAD SYSTEM
eleuation
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elevation
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Near future CAD system will equip additional large input
device which serve both as a input and a monitor. A current
working drawing may be shown on the large device, and at the
same time, the other monitor may keep showing another
drawings.
I will not say the future CAD system replaces pen and paper even if
the system will be more sophisticated tool. Those are fundamental tools for
designing, and it's almost impossible that the computer devices imitates
many kinds of paper quality and pen pressure. But it can be a real design
supportive tool which works almost same tool as pencils and papers, and
sometimes it will be more useful. And the CAD program as a rendering tool
will increase speed more and show more realistic, or sharper, pictures.
Consequently, the future CAD system will have both the actual design
function and the rendering function and will be utilized from the beginning to
the end of architectural projects.
This program has algorithm to create 3D coordinates from line
drawings on the screen. Therefore, many types of application programs can
be developed from this program,this program can be combined into another
application programs, such as 'mass volume calculation', 'shadow
simulation',etc. The following picture is just a possible user application
utilizing this program.
This program maintains 2D coordinates of original drawing
and 3D coordinates created by computer in the memory. By
modifying those coordinates, many applications can be
concerned.
PARTI: CAAD
Computer
Aided
Architectural
Design
BACKGROUND:
The development of computer aided design occurred in earnest
in the early 60's. The system allowed engineers to generate designs at
interactive graphics terminal, and manipulating drawing displayed on the
screen by use of light-pen and keyboard. Many that interactive computer
aided design system were installed in automobile and aero space firms
by the end of the 60's. Since then, computer aided design had been
increasingly widely employed in various aspects of mechanical, civil,
electrical, chemical., and industrial engineering.
The application of computer aided design in architecture
followed slowly behind application in engineering. The main reason of
slow response was obviously economic. Automobile and aerospace
firms are capable of investing capital in expensive equipment because of
the big budget for the design of one product, while the design cost must
be be kept to a small fraction of the project in architectural firms. Since
early CAD system costs hundreds of thousands or even millions of
dollars, they were out of concern of architects.
However, as the technology continued to develop, and as costs
of the system dropped significantly, it slowly became an reality to the
architects, and first installations of interactive computer graphics
systems in architectural offices began to appear in the early 70s.
Basic research in computer aided architectural design has been
supported by a few government and private agencies and private
foundations. Several universities, such as MIT, Pennsylvania State
University, Carnegie-Mellon University, etc, have carried out quite
extensive research programs. Some institutes have focused on building
description and space planning issues and also artificial intelligence
orientation. In addition to carrying out research activities, many school
of architecture now offer courses in computer aided design.
The 80's came about as a turning point of the computer aided
architectural design system. Network system was introduced in the
working area providing the opportunity of using big capacity
computers. And some computer languages were developed specially for
the purpose of computer graphics, such as AutoLISP. Moreover, low-
cost personal computer systems are developing quickly as well, and
increasingly being installed in architectural firms.
COMPUTER IN ARCHITECTURAL DESIGN:
The first 'successful' use of computers in architectural field was
in procedures where large amount of calculation were done, such as
structural and energy analysis, relieving designers from tedious tasks.
The next major advancement in CAD system came about with the
development of computer graphics, which are currently used as a
drafting tool by many designers. This use of computer, however, is still
limited and doesn't affect the actual design process. There are many
factors that architects don't use computer in the design. The main point
is that still pen and pencil is much, more convenient than the computer,
because architects have to deal with many information, theories and
problems at a same time, and designing goes back and forward all the
time. And abstract forms, which are mainly come from architects'
imagination and experience, is dealt in main design phase. Speaking of
the system, some programs have very good qualities, but the more
programs become powerful, the more commands users need to
remember. This is the most crucial point of present CAD system. The
next generation CAD system must aim to reduce the number of
commands maintaining present functions and each CAD command and
menu should be easy to use.
Even so, practically, the CAD system has great potential to be a
real architectural supporting system. The present system and program
are also very useful in terms of 3D view function, even though user
need to practice to operate efficiently. The CAD system can help
architects to transform design drawings directly into working drawings
and enable them to continue making design decisions throughout the
construction document phase. A consequence is that the preparatory
front-end work that is done early in a project becomes increasingly
important (Figure 1.1).
Accompanying with the Artificial Intelligence computer system
the CAD system will be able to deal with complicated tasks including
some thinking tasks. But it is not necessary to fully automate the
process of design in order to significantly improve design productivity
and quality. On the contrary, it is necessary to decide which tasks could
but should not be computed by the system and how computational and
manual design practices can be combined effectively without losing
design continuity.
INTERRELA TIONSUIP
BETWEEN COMPUTER AND DESIGN PROCESS:
Computer
Design Process
Free-hand drawing recognition
(straight line recognition)
(curved line recognition)
(comer recognition)
$
Error recognition & correction
(Interrelation among lines)
3D drawing recognition
(hidden line interpretation)
(hidden surface interpretation)
Data base
(environmental data)
(predefined furniture)
Dimension
(numerical factor)
Free-hand drawing or sketch
(rough)r |
1st stage drawing
(rough)
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