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sn#047846 filedate 1973-06-12 generic text, type C, neo UTF8
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C00001 00001
C00003 00002 PROPOSAL TO NSF - RANN - (Bernie Chern).
C00004 00003 1. IDEAS AND WORK ALREADY DONE.
C00007 00004 iv. Object Representation from Physical Measurement,
C00008 00005 v. Mechanical Simulation.
C00009 00006 2. PREVIOUS WORK AT STANFORD.
C00012 00007 3. RELATION TO WORK DONE ELSEWHERE.
C00013 00008 4. FACILITIES AT STANFORD A.I. LAB
C00014 00009 5. WHAT WE PROPOSE TO DO.
C00016 00010 Elements of a Geometric Modeling System.
C00018 00011 Five Version of a Geometric Modeling System.
C00019 00012 Itemize Shopping List.
C00023 00013 6. BUDGET
C00024 ENDMK
Cā;
PROPOSAL TO NSF - RANN - (Bernie Chern).
Principle Investigator - John McCarthy.
Co Principle Investigator - Bruce Baumgart.
This is a request for a grant of XXX to support
a two year research program in computer aided mechanical
drawing of three dimensional objects.
OUTLINE
1. Ideas and work already done.
2. Previous work at Stanford.
3. Relation to work done elsewhere.
4. Facilities at Stanford AI Lab.
5. What we propose to do.
6. Budget.
1. IDEAS AND WORK ALREADY DONE.
The proposed work is based on the following ideas and work
already done:
i. Explicit Object Representation.
An effective way of obtaining drawings of three dimensional
objects is to derive the drawing from an explicit computer model of
the three dimensional object. The orthographic, isometric and
perspective projections of the objects are obtained automatically
from the three dimensional description; with the hidden lines of the
object either eliminated, dashed or thinned; and with the appropriate
labels, dimensions, comments, and arrowheads indicated.
ii. Object Representation from Logical Description.
One convenient way of making an explicit computer model of
an object is to simulate the process of building the object; that is
the description of how to build an object is an implicit
representation of the object. For example it is more convenient to
describe Figure-1 implicitly as a unit cube with a regular five
pointed half unit star shaped hole through it; than as a list of the
locii of all the vertices; and the detailed specification of the
face, edge and vertex linkages; or worse yet having to draw the
object with a light pen.
iii. Model Building Primitives.
The simulated object building process
iv. Object Representation from Physical Measurement,
Another way getting an explicit computer model is to derive it
from measurements made on an actual physical object, 2D drawings, or
pictures. The physical object might be a clay or wood model of the thing
begin designed. We propose that a three dimensional object stereotype can
be accurately entered into a computer by means of a television camera
v. Mechanical Simulation.
Dynamic information such as the degrees of freedom of motion are
included in the object description and can be used to get pictures of the
objects in different positions. Moves of a mechanical arm design involving
vi. Photomeric Simulation.
vii. Robotics.
2. PREVIOUS WORK AT STANFORD.
This proposal is based on work by Bruce G. Baumgart as a
graduate student. Mr. Baumgart expects to complete his
dissertation entitled "Geometric Vision" in December 1973 and
will continue as a research associate on receiving his degree.
This work includes GEOMED, a Geometric Editor, which would
is the prototype of the mechanical drawing system we propose to build.
GEOMED is a 3D drawing program accessed thru a one character
jump table. GEOMED can construct arbitrary polyhedral objects and
display them with hidden lines eliminated. GEOMED can also accept
CRE's perceived images and form a polyhedral world model consistent
with such images.
GEOMEL is the bulk of GEOMED embedded in a LISP core image.
That is the subroutines comprising Geomed are accessible in LISP
notation, thus providing a geometric language for physical world
modeling and physical action simulation.
GEOMES is the bulk of GEOMED embedded in a SAIL core image.
That is the subroutines comprising GEOMED become SAIL accessible.
TVFONT is for making type font bit arrays from television
images, or for rescaling existing fonts.
CRE is converts a sequence of digital television images
into a video intensity contour data structure. Auxiliary routines of
CRE provide cart and turntable control and XGP video output.
3. RELATION TO WORK DONE ELSEWHERE.
4. FACILITIES AT STANFORD A.I. LAB
1. Time Sharing System - its relevance.
2. III displays
3. Data Disc displays.
4. XGP printer
5. Output for FR-80.
5. WHAT WE PROPOSE TO DO.
We propose to represent and simulate solid objects in a
computer for the sake of mechanical design, mechanical drawing and
robotics. Our two year goal will be to automate as much as possible
the task of creating and altering three dimensional data structures
from which mechanical drawings can be derived; this work would also
be a step towards solving the problem of representing physical
objects for a robot. The overall project to date has been called
"geometric modeling" a term which we use to refer to our particular
combination of computer graphics, physical world modeling, image
processing and geometry. Accordingly, the details of the work we
propose doing will be presented in terms of the elements comprising
a Geometric Modeling System, GMS, and in terms of the several
versions of such a system that we believe necessary or possible to
build. (The reader interested only in an itemized list of project
goals is advice to skip to the end of this section).
Elements of a Geometric Modeling System.
Like a computer, the four main elements of a geometric
modeling system are memory, process, input and output. Starting with
memory, there are the problems of representation (how to describe a
physical object); accessing (how to find a particular description by
name, by location, or by whether it is currently in view); and
efficiency (how to keep the size of storage space down and how to
dynamically allocate fast and slow memory resources).
As mention before, our GMS has explicit and implicit
representations. The presently implemented explicit representation
is based on polyhedron models of solid rigids objects. A simple
object called a body is defined be surface shell composed of faces,
edges and vertices (that satisfy the Euler equation V - E + F = 2);
such polyhedron bodies are combined to form compounded objects. At
present a simple curved object is represented by approximating it to
the desired accuracy with a polyhedron composed of flat polygonal
faces. We propose elabor
Five Version of a Geometric Modeling System.
1. Present version. 1973-1974.
Polyhedron based modeling.
2. Intermediate version. 1974-1975.
Manifold based modeling.
3. Advanced version. 1975.
Mechanical simulation.
Photometric simulation.
4. Standard version. FORTRAN.
5. Small Machine Version. PDP-11.
Itemize Shopping List.
Ignoring the overall system organization and fine details,
the goals of the proposed project are summarized in the following
shopping list:
Items partially in hand.
1. Representation of solid rigid three dimensional polyhedra.
2. Language extension of geometric primitives.
3. Language extension of object building primitives.
4. Polyhedron object hidden line eliminator.
5. Geometric editor.
Items within one year's work.
6. Generation of ordinary mechanical drawings from geometric models.
7. Representation for curved objects.
8. Representation for flexible objects.
9. Video acquisition of two dimensional drawings.
10. Mechanical simulation and animation.
Second Year and Elective Items.
11. Generation of high quality mechanical drawings, such as
assembly drawings and cut away layout drawings.
12. Development of a remote display terminal version of the system.
13. Development of a standard FORTRAN version of a subset of the system.
14. Mechanical drawings for a special area of engineering;
(pipefitting, screw threading, mining, or whatever).
Basic research items.
15. Video acquisition of three dimensional objects.
16. Photometric simulation - shadows, multiple light sources, etc.
generation of high quality video appearance.
To elaborate, substantial work has already been done on the
first five items listed; so that the most pessimistic and
conservative estimate of our potential achivevements over the next
two years should include the documentation, publication and
elaboration of the research work already done. Our intermediate
expectations include making considerable progress and original
contribution with respect to the first five items as well as being
able to get a substantial start on item numbered six thru ten; as
well as doing one of the four items eleven, twelve, thirteen or
fourteen. Finally, our optimistic expectations and scientific
horizon lies in getting a computer to be able to reduce live video
input into a mechanical model and to output realistic looking video
from a mechanical model.
6. BUDGET
1. Baumgart
2. A programmer.
3. A graduate student.
4. Two high quality display terminals.
e.g. Systems concept's best.