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Claims  |
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I claim:
1. In a computer-assisted design system, a method for providing surface
detail to computer generated two-dimensional graphic images of
three-dimensional surfaces to create a three-dimensional appearance
comprising:
generating a perspective mesh on said computer-generated two-dimensional
graphic image such that said mesh creates a three-dimensional visual
appearance;
mapping surface detail to said mesh point-by-point such that said surface
detail produces a three-dimensional appearance; and
producing a graphic visual image of said two-dimensional graphic image with
said surface detail applied.
2. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 1, wherein the step
of generating a perspective mesh comprises:
dividing said two-dimensional image into segments, each segment
representing a portion of said three-dimensional object;
circumscribing each of said segments by polygons; and
calculating a perspective mesh for each segment circumscribed by each said
polygon, said perspective meshes each comprising a plurality of horizontal
and vertical lines spatially arranged to form a plurality of
quadrilaterals representing the three-dimensional surface forms for said
three-dimensional object.
3. A method for providing surface detail to computer-generated
two-dimensional graphic images as in claim 1, wherein said step of mapping
comprises:
a. scan-converting each quadrilateral within said mesh;
b. calculating a surface detail coordinate for each pixel lying within each
segment based on the location of the pixel in the quadrilateral and on the
location of the quadrilateral in the mesh;
c. mapping the surface detail coordinates to the array of pixel making up
the selected surface detail and selecting the appropriate pixel;
d. repeating steps a-c for every pixel in the quadrilateral scan line, and
for every scan line in the quadrilateral, and for every quadrilateral in
the mesh.
4. In a computer-assisted design system, a method for providing surface
detail to computer generated two-dimensional graphic images of
three-dimensional surfaces to create a three-dimensional appearance
comprising:
a. producing a two-dimensional image of a three-dimensional object in a
digital form for storage and processing by a digital computer;
b. dividing said two-dimensional image into segments, each segment
representing a portion of said three-dimensional object;
c. circumscribing said segments by polygons in digital form for storage and
processing by said digital computer;
d. generating at least one mesh within each segment wherein said at least
one mesh creates a three-dimensional visual appearance;
e. repeating steps b-d until meshes have been generated for all segments of
said two-dimensional image;
f. storing said segments with said meshes in a data storage unit;
g. producing at least one image of surface detail in the form of a
rectangular array of pixels for storage and processing by a digital
computer;
h. storing said surface detail images in said data storage unit;
i. mapping said surface detail to said mesh within each said segment such
that said surface detail produces a three-dimensional appearance; and
j. producing a graphical visual image of said two-dimensional image covered
by said surface detail wherein said image presents a three-dimensional
appearance.
5. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 4 wherein said step
of producing a two-dimensional image comprises:
forming a video image of said three-dimensional object; and
converting that video image into a digital form suitable for storage and
processing by a digital computer.
6. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 4 wherein said step
of producing a two-dimensional image comprises:
creating a graphic representation of said three-dimensional object in
two-dimensional form; and
converting said graphic representation into a digital form suitable for
storage and processing by a digital computer.
7. A method for providing surface detail to computer generated
two-dimensional graphic images as set forth in claim 4 wherein said step
of circumscribing said segments comprises:
displaying said two-dimensional image on a graphic visual input/output
device; and
forming polygons around each segment as displayed on said graphic visual
input/output device.
8. A method for providing surface detail to computer-generated graphic
images as set forth in claim 7 wherein said step of forming polygons
comprises:
entering information representing the boundaries of said polygons into said
computer using a computer input device.
9. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 4 wherein said step
of generating at least one mesh comprises:
displaying at least one of said segments bounded by said polygon on a
graphic visual input/output device;
entering information into said computer for creating a series of bounding
polylines which enclose each said segment; and
calculating a perspective mesh contained by said bounding polylines which
perspective mesh consists of a plurality of horizontal and vertical lines
spatially arranged to form a plurality of quadrilaterals representing a
three-dimensional surface for each said segment, as such three-dimensional
surface would appear to the eye, in two-dimensional form.
10. A method for providing for providing surface detail to
computer-generated two-dimensional graphic images as set forth in claim 9
further comprising:
modifying the locations of points lying within said perspective mesh to
effect local changes in the shape of the mesh.
11. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 10 wherein said step
of modifying the locations of points comprises:
A. entering x, y coordinates into said computer for a point within said
mesh;
B. comparing the x, y coordinates entered in step a. with stored x, y
coordinates for the existing mesh;
C. selecting the stored x, y coordinates closest to the x, y coordinate
entered in step a.;
D. entering a second x, y coordinate into said computer, said second x, y
coordinate representing the desired modification; and
E. replacing the stored x, y coordinate with said second x, y coordinate.
12. A method for providing surface detail to computer-generated
two-dimeinsional graphic images as set forth in claim 9 wherein said step
of calculating a perspective mesh comprises:
calculating the intersection of said bounding polylines; and
generating a perspective mesh based on those bounding polylines.
13. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 9 further comprising:
controlling the interior shape of said mesh by entering information into
said computer for creating additional horizontal polylines and additional
vertical polylines within each segment circumscribed by said boundary
polylines, said additional vertical and horizontal polylines creating
sub-areas within each said segment.
14. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 13 wherein said step
of calculating a perspective mesh comprises:
calculating the intersection of all vertical polylines including the
vertically disposed bounding polylines with all of said horizontal
polylines including the horizontally disposed bounding polylines;
generating temporary interior boundary polylines for each sub-area;
generating a perspective mesh for each sub-area based on those temporary
interior boundary polylines; and
creating a composite perspective mesh for each said segment for each
perspective mesh generated for each sub-area.
15. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 9 wherein said step
of entering information into the computer for creating a series of
bounding polylines comprises:
entering at least two polypoints into the computer which polypoints form
each of said bounding polylines.
16. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 15 further
comprising:
modifiying said bounding polylines by moving, deleting, or inserting at
least one of said polypoints forming said bounding polylines.
17. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 9 wherein said step
of producing at least one image of surface detail comprises:
entering at least one image of at least one surface detail feature into the
computer in such form as to permit display on a graphic visual
input/output device; and
storing at least a portion of said surface detail image in a data storage
device through storing the information necessary to define the color and
intensity attributes of each elemental point on the graphic input/output
device displaying said image, such information thus defining a rectangular
array of pixels representing the surface detail.
18. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 17 wherein said
surface detail comprises a pattern.
19. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 17 wherein said
surface detail comprises texture.
20. A method for providing surface detail to computer-generated
two-dimensional graphic images as set forth in claim 17 wherein said step
of mapping comprises:
A. selecting a segment of the two-dimensional image to which surface detail
is to be applied;
B. selecting the surface detail to be applied;
C. retrieving the selected segment and mesh from data storage;
D. retrieving the selected surface detail from data storage;
E. scan-converting the x, y points forming the boundary of the selected
segment by creating and storing a list of scan lines contained within the
selected segment;
F. examining each quadrilateral within said mesh to determine whether any
part of said quadrilateral lies within the bounding polylines of the
selected segment;
G. scan-converting each quadrilateral in said mesh, wherein at least a
portion of said quadrilateral lies within the bounding polyline of the
selected segment, by converting and temporarily storing a list of scan
lines for each quadrilateral;
H. examing each scan-line from step g. on a pixel-by-pixel basis to
determine those pixels lying within the selected segment;
I. calculating a surface detail coordinate for each pixel lying within the
selected segment based on the location of the pixel in the quadrilateral
and on the location of the quadrilateral in the mesh;
J. mapping the surface detail coordinates back to the array of pixels
making up the selected surface detail and selecting the appropriate pixel;
K. blending the surface detail pixel color and the pixel color at this
position in the mesh;
L. repeating steps e-k for every pixel in the quadrilateral scan line, for
every scan line in the quadrilateral, and for every quadrilateral in the
mesh.
21. a system for providing surface detail to computer-generated
two-dimensional graphic images in a computer-assisted design system of
three-dimensional free-form surfaces to create a three-dimensional
appearance comprising:
means for producing a two-dimensional image of a three-dimensional object
in a form for storage and processing by a digital computer;
means for dividing said two-dimensional image into segments, each segment
representing a portion of said object;
means for circumscribing said segments by polygons in digital form for
storage and processing by a digital computer;
means for generating at least one mesh within each segment wherein said at
least one mesh creates a three-dimensional visual appearance;
means for producing at least one image of surface detail in the form of a
rectangular array of pixels for storage and processing by a digital
computer;
means for storing said surface detail image in a data storage unit
accessable by said digital computer;
means for mapping said surface detail to said mesh within said segment such
that said surface detail produces a three-dimensional appearance; and
means for creating a graphic visual image of said two-dimensional image,
covered by said surface detail, giving a three-dimensional appearance.
22. A system for providing surface detail as set forth in claim 21 wherein
said means for producing a two-dimensional image comprises:
means for forming a video image of the three-dimensional object; and
means for converting said video image into a digital form suitable for
storage and processing by additional computer.
23. A system for providing surface detail as set forth in claim 21 wherein
said means for producing a two-dimesional image comprises:
means for creating a graphic representation of said three-dimensional
object in two-dimensional form; and
means for converting said graphic representation into a digital form
suitable for storage and processing by a digital computer.
24. A system for providing surface detail as set forth in claim 21 wherein
said means for circumscribing said segments comprises:
means for displaying said two-dimensional image on a graphic visual
input/output device; and
means for entering information into said computer representing polygons
formed around each segment as displayed on said graphic visual
input/output device.
25. A system for providing surface detail as set forth in claim 21 wherein
said means for generating at least one mesh comprises:
means for displaying at least one of said segments bounded by said polygon
on a graphic visual input/output device;
means for entering information into the computer for creating a series of
bounding polylines which enclose said segment; and
means for calculating a perspective mesh contained by said bounding
polylines perspective which mesh consists of a plurality of horizontal and
vertical lines spatially arranged to form a plurality of quadrilaterals
representing a three-dimensional surface for said segment, as such surface
would appear to the eye, in two-dimensional form.
26. A system for providing surface detail as set forth in claim 21 wherein
said means for producing at least one image of surface detail in the form
of a rectangular array of pixels comprises:
means for entering at least one image of at least one surface detail
feature into the computer in such form as to permit display on a graphic
visual input/output device; and
means for storing at least a portion of said surface detail image in a data
storage device, said storage device permitting the storing of information
necessary to define the color and intensity attributes of each elemental
point on the graphic visual input/output device displaying said image,
such information defining a rectangular arrray of pixels representing the
surface detail.
27. A system for providing surface detail as set forth in claim 21 wherein
said means for mapping comprises:
means for selecting a segment of the two-dimensional image to which said
surface detail is to be applied;
means for selecting the surface detail to be applied;
means for retrieving the selected segment and mesh from data storage;
means for retrieving the selected surface detail from data storage;
means for scan-converting the x, y points forming the boundary of the
selected segment by creating and storing a list of scan lines contained
within the selected segment;
means for examining each quadrilateral in said mesh to determine whether
any part of said quadrilateral lies within the bounding polylines of the
selected segment;
means for scan-converting each quadrilateral in said mesh and temporarily
storing a list of scan-lines for each quadrilateral;
means for examining each scan-line on a pixel-by-pixel basis to determine
those pixels lying within the selected segment;
means for calculating a surface detail coordinate for each pixel lying
within the selected segment based on the location of the pixel and the
quadrilateral and on the location of the quadrilateral in the mesh;
means for mapping the surface detail coordinates back to the array of
pixels making up the selected surface detail and means for selecting the
appropriate pixel;
means for blending the surface detail pixel color and the pixel color at
this position in the mesh. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is in the field of computer aided design ("CAD") systems, and
specifically relates to a system and method for providing texture mapping
to a two-dimensional design system.
The present invention has specific application to the apparel and footwear
design industries.
2. Background Description
In the field of computer aided design, one of the objectives of any CAD
system is to display a realistic image of whatever is being designed on
the graphic visual input/output device, e.g. cathode ray terminal ("CRT"),
of the system. One technique for enhancing the realism of the generated
image is to add detail to the surfaces or areas making up the image using
a texture mapping technique. That has been employed in three-dimensional
CAD systems, notably those used in making animated films. The objects
designed on and displayed by such systems are represented internally by a
data structure that reflects the three-dimensional topology of the object.
The texture mapping algorithms incorporated into those systems use that
topology as a guide for applying the texture over the surface of the
object in a realistic manner. Procedural Elements for Computer Graphics by
David Rogers, pp. 354-363 (McGraw-Hill 1985); "Texture and Reflection
Computer Generated Images" by James F. Blinn and Martin E. Newell, pp.
542-547, Communications of the ACM, (Oct. 1976); "Simulation of Wrinkled
Surfaces" by James F. Blinn, Computer Graphics, Vol. 12, Proceedings of
SIGGRAPH (1978) pp. 286-292. In order to obtain that realism, the texture
applied to any surface of the object that is not perpendicular to the
viewing direction (line of sight) must show distortion to give the
appearance of being "tipped away" from the viewer; the applied texture
should be shaded the same as the object based on a light source at a given
location; the texture should appear larger near the front of the object
and smaller near the back due to perspective; and, the texture should not
appear if it is mapped to a surface that is on the back of the object.
Those are a few of the visual cues that a texture-mapping algorithm used
in a three-dimensional CAD system can give a user to enhance the
three-dimensional appearance of the object being designed.
Those systems, however, are complicated and require comparatively large,
expensive computer systems. Moreover, there is a need to be able to
provide texturing which would provide for a three-dimensional appearance
for two-dimensional CAD systems.
In the case of a two-dimensional CAD system, the image on the graphic
visual input/output device, i.e. CRT, may have been drawn freehand by the
user or may be a digital photograph that was input via a video camera. In
any case, the data structure describing the three-dimensional topology of
the object or image being designed does not usually exist in a
two-dimensional CAD system; hence there is no well-defined procedure by
which surface detail may be "correctly" applied to the different parts of
the image. That is the problem the present invention addresses.
SUMMARY OF THE INVENTION
Once an image has been displayed on the graphic input/output device or CRT
of a two-dimensional CAD system, the present invention provides the user
with a capability of creating perspective meshes that cover different
parts of the image in such a way as to give the appearance of describing
the three-dimensional topology of the underlying image. The user is given
the "tools" for controlling how the perspective meshes cover the image;
these are used for the initial placement of the mesh and subsequent
adjustment of the mesh until the user feels that it adequately describes
the shape of the underlying surface.
A "perspective mesh", as used herein, is a mesh created by a plurality of
horizontal and vertical lines which form a number of quadrilaterals. The
horizontal and vertical lines are spatially arranged such that the
resulting image is a representation of a three-dimensional form, or, in
short, represent the three-dimensional image as it might appear to the
eye, but in two-dimensional form.
In the case of apparel design, the present invention gives the user, for
the first time, the capability to place a mesh over a piece of material in
such a way as to follow any curves in the shape, as well as follow the
contours of any folds and wrinkles. If the image is of a room interior,
meshes can be placed on curtains or furniture in the scene so that surface
detail (in this case fabrics, patterns and so forth) can be applied to
their surfaces in a realistic manner. A mesh can also be placed on a floor
in a room in such a way as to show perspective, allowing different carpet
patterns and color to be applied to the floor.
After meshes have been applied to the different parts of the image, the
present invention permits the use of surface detail mapping to apply the
surface detail to the parts of the image that are covered by the meshes. A
surface detail mapping function in a three-dimensional CAD system uses the
actual topology of the object being designed as a guide when applying the
surface detail to the parts of the object. For the purpose of summarizing
the present invention, a surface detail mapping method of the present
invention uses the user-defined meshes which have been developed as
described above.
In the apparel industry, the present invention now permits a designer to
use a video camera or digitizing drafting tablet to enter an image of a
model, for example, wearing a dress of a particular design into the
computer of a two-dimension CAD system. That stored image can be retrieved
to a CRT or other graphic visual input/output device which then presents a
two-dimensional image of the model and the dress. In order to obtain a
three-dimensional appearance, the designer, using the present invention,
creates a perspective mesh overlaying the dress which now gives the
designer the ability to represent, in two-dimensional form, the actual
three-dimensional surface. The designer then retrieves various surface
details (in this case, various cloth/materials having differing textures,
weaves, patterns, colors, and the like) from computer storage and can
easily "dress" the model on the CRT with those differing textures, weaves,
patterns and the like until a final design is reached. The designer can
then produce a hard-copy image of the resulting design.
In interior design, the present invention permits a designer to use a video
camera, for example, and take a video image of an actual room and then,
using the mesh generation and surface detail mapping techniques of the
present invention, change the texture, pattern and colors of floor
coverings (i.e. carpet), window treatments (i.e. drapes and the like), and
other room features until a final design is reached. Rather than guessing
how a particular carpet will look in a particular room, the design can now
actually "lay" the carpet in the room using a CAD system and see how the
carpet looks in a three-dimensional representation.
Thus, it is an object of the present invention to provide a system and
method for providing surface detail to computer generated two-dimensional
graphic images of apparel or other free-form surfaces and
three-dimensional objects.
It is another object of the present invention to provide a user-controlled
mesh generation system and method for producing a topology for a
two-dimensional graphic image of a three-dimensional free-form surface or
object.
It is a further object of the present invention to provide a system and
apparatus for applying surface detail to a two-dimensional graphic image
which gives the image a three-dimensional appearance.
It is yet a further object of the present invention to provide a simpler
system and method for providing surface detail in CAD systems, and one
requiring comparatively less expensive and complicated computer hardware
and systems.
It is yet another object of the present invention to provide a system and
method which permits a user to provide visual images of a variety of
apparel or other designs illustrating differing surface textures, patterns
and colors, which images give a three-dimensional appearance.
It is a still further object of the present invention to provide a system
and method which allows a user to input to a two-dimensional graphic
system the image of a room, apparel design, or other free-form
three-dimensional surface and then vary, at the user's will, the surface
texture, pattern and colors of selected portions of that image, for
example floor and wall coverings, window treatments, apparel fabric and so
forth.
These and other objects, features and advantages of the invention will
become evident in light of the following detailed description, viewed in
conjunction with the referenced drawings, of a preferred Texture Mapping
System according to the invention. The foregoing and following description
of the invention is for exemplary purposes only. The true spirit and scope
of the invention is set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of a CAD hardware system useful in the present
invention.
FIG. 2 is a flowchart illustrating a portion of the two-dimensional CAD
system according to the present invention.
FIG. 3 is a flowchart illustrating the mesh generation functions of the
present invention.
FIG. 4 is a flowchart illustrating the polyline input functions of the
present invention.
FIG. 5 is a flowchart illustrating a portion of the polyline input
functions of the present invention.
FIG. 6 is a flowchart illustrating the "Move Polypoint" function of the
present invention.
FIG. 7 is a flowchart illustrating the "Delete Polypoint" function of the
present invention.
FIG. 8 is a flowchart illustrating the "Insert Polypoint" function of the
present invention.
FIG. 9 is a flowchart illustrating the mesh generation function of the
present invention.
FIG. 10 is a flowchart illustrating the mesh editing function of the
present invention.
FIG. 11 is a flowchart illustrating the mesh storing function of the
present invention.
FIG. 12 is a flowchart illustrating the store texture or pattern of the
present invention.
FIG. 13 is a flowchart illustrating the first portion of the mapping
function of the present invention.
FIG. 14 is a flowchart illustrating the second portion of the mapping
function of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Although the current invention has particular application in the apparel
industry and the following description focuses on that application, it
should be understood that the invention may be applied in any instance
involving a three-dimensional object.
For purposes of this description, there are a few assumptions made about
the nature of the two-dimensional images that are displayed on standard
graphic CRTs of CAD systems which are to be used as a backdrop for mesh
generation and subsequent application of surface detail. The
two-dimensional image being worked on should be realizable as a set of
constituent parts that, though perhaps appearing to be a three-dimensional
object, are simply the projection into two dimensions of the parts making
up the object. The individual parts making up the object (in the case of
apparel: sleeves, fronts, yokes, etc.) are then bounded by two-dimensional
polygons, each of which contains a region of the image that consists of a
single piece of material, and as a collection cover all pieces of material
or parts making up the image. Those polygons are referred to as "segments"
and may be applied to the image point by point via a manual digitizing
process using a locating instrument such as a standard light pen or mouse.
The two-dimensional image may have been input to the CAD system through a
video camera or by being sketched in directly by the user. Once in the
system, the image is stored on a data storage system, preferably a hard
disk, for later retrieval. The definition of the segments digitized by the
user to define the image parts are stored with the image.
After an image has been segmented, the user may then generate the meshes
which will guide the texture mapping, with one mesh per segment. The
segments used to subdivide the image will usually each cover one part or
piece of material; the associated mesh that the user places on the segment
will then determine how the surface detail will then be applied to that
piece of material.
To define a mesh, the user first digitizes four bounding polylines, the
`top`, `left`, `bottom`, and `right`. This is done in a manner similar to
that done in digitizing the boundary of the segment. In fact, it is often
useful to use portions of the boundary of the segment as part of the
polylines making up the mesh boundary. Once the boundary polylines of the
mesh have been digitized, the user can repeatedly generate the mesh
bounded by the polylines while making changes to the polylines using
editing functions (for example, instructions to move polyline point,
insert, delete and so forth) until the shape of the mesh looks like it
fits correctly over the underlying surface. An editing function for
adjusting the points singlely inside the mesh may be used to make small
adjustments in the appearance of the interior of the mesh. Another method
for adjusting the interior of a generated mesh without changing the border
or the mesh in the vicinity of the border is to actually digitize interior
polylines, thus creating "sub-meshes" of the original mesh. Such technique
gives the user a more general ability for controlling the interior shape
of the mesh. The meshing algorithm is then applied recursively to create
each of the sub-meshes, which as a whole make up the complete mesh. When
the user is satisfied that the mesh is shaped correctly over the image
surface under the segment, the user may then store the mesh with the
associated segment.
Once a mesh has been created and stored with an image segment, the user may
then apply surface detail to the segment using the texture mapping
function of the present invention. The texture mapping function will then
use the mesh associated with the segment as a guide for applying the
surface detail to the portion of the image under the segment. The "surface
detail", also known as "textures" or "patterns", may be digitized images
brought into the system via video camera input, or they may have been
designed using other facilities. Those facilities may be "paint" programs,
fabric weaving programs, or patterning programs or some of the other
functions in standard two-dimensional CAD systems. The textures or
patterns (and images, for that matter) are stored on the data storage
device, e.g. system hard disk, as a rectangular array of pixels.
Description of Hardware
The hardware requirements to support the present invention are basically
those needed to support a standard two-dimensional CAD and image
processing system. An illustration of such a system is given in FIG. 1.
The hardware should consist of, minimally, a graphic visual input/output
device, e.g. a CRT, 10 and 10', with a standard light pen 12 or mouse 14
as a locating instrument, a keyboard 16, a central processing unit 18 that
will support program control of the individual pixels displayed on the
graphic CRT 10 and 10' (through use of graphics command library), and a
data storage unit 20, preferably a hard disk storage unit. If the images
used in the system are to be inputted through a video input, a video
camera 22 and standard associated frame-grabbing hardware (not shown) are
also required. Input to the system may also be through a standard
two-dimensional digitizing drawing device 32. The data storage unit 20 is
needed for storage of the data files supporting the two-dimensional
software system including the digital graphic images, segments and meshes
thereon, and the textures, patterns, fabrics, etc., also stored as digital
images for application as surface detail to the segments on the graphic
images. For the mesh generation capability, the central processor should
support floating-point mathematics computation. Another consideration is
the number of simultaneously displayable colors possible on the graphic
CRT 10 and 10' of the computer system; a minimum of 256 simultaneously
displayable colors and preferably 4096 would be needed in a system with
video camera input and colorization or texture mapping performed by the
software. Adequate facilities for performing these functions are found in
the "Engineering Workstations" currently available from several vendors
such as Silicon Graphics Inc., Apollo Computer Inc., and SUN Microsystems.
The present invention is preferably used in conjunction with a Silicon
Graphics Inc. IRIS workstation, currently configured with a keyboard,
three-button mouse, graphic CRT with a viewable resulution of 768 by 1024
pixels, a central processor with 2 megabytes of main memory and supporting
4096 simultaneously displayable colors on a graphic CRT, and a 72 megabyte
hard disk. Television input of images and textures are supported using a
video camera and a video frame buffer. A system configured with greater
viewable resolution, or more simultaneously displayable colors would
permit even better visual results.
The output of the system can be directed in known manner to a video tape 24
for later viewing, an output camera 26 capable of producing color slides
or photographs of various sizes, a graphic CRT 10' (which, of course, may
be the same as the input graphic CRT 10), or to hardcopy for example
through a printer 28, or a plotter 30.
Description of Software
In describing the functions of the present invention involved in applying
surface detail to two-dimensional images such that the "three-dimensional
appearance" is provided or enhanced, two groups of functions need to be
detailed. The first is the set of functions used for defining, generating,
editing, and storing a mesh. The second is the set of functions used for
storing textures and patterns and applying them to the image. Since most
current CAD systems are menu driven, the explanations given below will
describe how the user would execute the functions by selecting from a menu
displayed on the graphic CRT of the system.
Basic capability for creating and adjusting meshes can be provided in a
menu with the following choices:
Top Polyline
Left Polyline
Bottom Polyline
Right Polyline
Generate Mesh
Modify Mesh Points
Store Mesh With Segment
The functions "Top Polyline", "Left Polyline", "Bottom | | |
