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Description  |
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BACKGROUND OF THE INVENTION
The invention is in the field of computer-aided design (CAD) systems, and
specifically relates to a system and method for simulating woven fabric
surface detail with emphasis on realistic thread interlacing and color
blending. Immediate applications of the present invention are apparel and
textile design industries.
Preparation of fabric sample swatches costs millions of dollars for the
textile mills and thousands of man hours in the design studio annually.
Because of the tremendous amount of time involved, mills and designers are
forced to work on fashion styles and trends at least a year in advance in
order to cope with the time-consuming process of sample swatch
preparation. From the mills' standpoint, the sample swatch operation
intervenes the normal production schedule, increases machine down-time,
and wastes human and natural resources. From the designer's standpoint, it
delays response to the market changes, causes uncertainty in forecasting
future styles and fashion trends, and wastes valuable human creativity.
The present invention addresses all of the above problems.
In the field of computer-aided design, one of the objectives of any CAD
system is to realistically simulate an image of an object, including
color, shape, and construction, on a graphic visual input/output device,
such as a cathode ray terminal (CRT). In case of woven fabric, surface
detail modeling to capture the intricacies of thread interlacing and
multiple shades of color threads are not possible to achieve through the
practice of traditional symbolic representation of weaves. Because threads
are actually represented by solid color blocks in known prior art systems,
the interlacings between warp ends and filling picks are painted according
to the format of grid paper, where the grids marked by an "X" are painted
with the color of warp ends and the blank grids are painted with the color
of filling picks.
In a real situation, however, threads are shaded by various light sources.
The spinning of fibers also creates shaded visual appearance. In addition,
the interlacing between warp ends and filling picks produces shading
variation. Therefore, all the shades generated by various factors as
mentioned above, must be seriously taken into consideration when two sets
of warp and filling threads are interlaced together in order to obtain a
realistic woven fabric surface detail. A graphic, instead of symbolic,
approach provides all the possibilities to address the problems mentioned,
since graphic representation of woven fabric physically simulates each
individual thread going up and down over one another in the fabric
surface. The ability to design and construct yarns used in such a woven
fabric is also crucial to obtaining a realistic image of a woven fabric on
the traffic visual input/Output device. Designing and constructing
multi-color threads require the twisting of pre-dyed fibers of different
colors in order to achieve the visual appearance of color randomness. The
symbolic designing of woven fabric, as a matter of fact, over-simplifies
the complexity of surface detail. Moreover, the lack of ability to design
and construct multi-color threads makes it beyond the reach of symbolic
approaches to achieve the realism of woven fabric on the graphic visual
input/output device of a CAD system. Those are the problems the present
invention addresses.
SUMMARY OF THE INVENTION
The present invention provides a unique solution to the simulation of
spinning fibers to form a yarn, generating weaves in almost limitless
variations, and preparing a woven fabric surface in detailed finished
form, in order to eliminate the costly and time-consuming practice of
sample swatch preparation.
The present invention provides the user with the capability of constructing
spun and non-spun yarns which may be of staple or filament fibers. The
user is provided a design input for the cross section of a yarn by placing
various shapes of natural and man-made fibers or fiber strands together,
and then is provided tools for spinning or entangling the cross section to
make a spun yarn. In order to generate a spun yarn, the user has the
choice of "REGULAR" and "NOVELTY" options to selectively generate a
"fixed" number of turns-per-inch (TPI) or a "random" number of
turns-per-inch along the length of a yarn. Also, the user is provided a
selection of the spinning direction between clockwise and
counterclockwise. As the fiber layout is executed, an enlarged
longitudinal side view of a resulting yarn, plus several reduced diameter
side views more closely matched to actual thread sizes in three-pixel,
two-pixel, and one-pixel wide yarns, are shown side-by-side on the graphic
CRT. When the yarn design is complete, the user may, if satisfied, save
the yarn in a data storage unit, such as hard disk or tape, for later
retrieval, or may modify the fiber layout and reexecute the automated
image generation.
The invention is also capable of simulating non-spun threads. The user may
use the "paint box" function to design or construct the fiber layout in
longitudinal side view of a yarn. Without the twisting process, the fiber
layout in longitudinal side view is resized to usable three-pixel,
two-pixel, and one-pixel diameters which are displayed on the graphic CRT.
This feature presents a great deal of potential for designing and
constructing a variety of novelty yarns, such as air-textured, slub, loop,
and nep yarn, etc.
The invention further provides for weave patterns through either user
creation, retrieval, or available through default in order to apply yarns
which had been previously constructed and saved on a data storage unit, to
simulate a woven fabric surface detail. The present invention provides all
the "tools" required to generate various weaves, mainly for Dobby and Cam
looms. The five known basic weaves, including plain, twill, rib, satin,
and basket may be developed with the user selecting parameters compatible
with the desired weave and the system initialized with the remaining
parameters. Variations of those five basic weaves and completely unique
weave patterns may be obtained through the capability of the user's
manipulation of the lifting sequences of harnesses known as "chain draft"
("CD") and the drawing sequence of warp ends through harnesses known as
"drawing-in draft" ("DID"). The design of the weave may be visualized in
both graphic and symbolic representations. As a desired weave is created,
the user may save it on a data storage unit for retrieval later, or may
use it for the simulation of woven fabric surface detail. Moreover, an
important and useful feature is provided for reversing the CD/DID
manipulation. The user is provided tools for designing random weave
patterns which are displayed on the graphic CRT. The system determines the
optimum CD and DID for the user's design including the minimum number of
harnesses required to weave the design. The user is able to experiment
with a variety of weave structures and evaluate their cost-effectiveness
by comparing the minimum number of harnesses required, as the cost of
manufacturing is proportional to the number of harnesses used in the
weaving process.
Another aspect of the present invention is the ability to use existing
yarns and weaves to obtain a realistic image of woven fabric surface
detail on a graphic CRT. The present invention provides a set of functions
for the user to retrieve, apply, edit, browse, and construct yarns and
weaves. A set of current warp and filling thread layout is displayed on
the graphic CRT. Default warp and filling thread layout will be presented
unless there is an existing thread layout. However, the present invention
provides complete flexibility for the user to edit the warp and filling
thread layout before the design is generated. For example, the user may
pick a color from the color palette to tint the thread layout or may
browse yarns from a data storage unit and assign them to the layout. In
addition, the present invention allows the user to "GROUP" threads of the
warp and filling layout. A bracket indicating a group of threads will be
shown over the top of warp layout or to left of filling layout. After a
group of threads is made, these grouped threads will be treated as a
single thread. This feature provides for the design of complicated plaids.
One button stroke from the locating device will tint or replace an entire
group of threads with a new color or a new yarn.
Moreover, the present invention allows the user to delete threads from the
warp and filling layout, assign different ends-per-inch (EPI) and
picks-per-inch (PPI) to the warp and filling layout and vary the thread
repeat lengths from five inches to one-inch lengths (in one-inch
increments). The maximal fabric dimension allowed is 1240 warp threads by
1240 filling threads. However, due to the size of the CRT, only 293 warp
and 233 filling threads can be shown on the graphic CRT simultaneously.
Therefore, the present invention provides a set of functions which allow
the visualization of any portion of the warp and filling layout via image
scrolling on the CRT screen.
Once a satisfactory warp and filling thread layout is found, the user may
execute the entire warp and filling layout or only a portion of layout by
specifying the area of interest to be woven. The image of the woven fabric
includes shading of portions of each warp and fill thread determined as a
function of the relative diameters of the threads and the over/under
relationship of the thread portions. In this manner, the present invention
provides an exceptionally realistic image of the woven fabric surface.
Once created, woven fabric designs, including the thread layouts that
generated them, may be stored for later retrieval. Fabric image may be
resized down to an approximate life-size without losing the surface detail
of the woven fabric.
It is the objective of the present invention to provide a method for the
textile and apparel industries to improve or revolutionize their
traditional sample swatch preparation processes. From the beginning to the
end, the present invention provides the user a systematic method for
designing and visualizing multi-color shaded threads, generating and
manipulating various weave patterns, and combining both yarns and weaves
to create woven fabric images having very realistic surface detail,
including appropriate shading of the portions of the yarn which define the
fabric. The present invention may be used as a stand-alone system for the
sole purpose of designing surface detail of woven fabrics, or as a portion
of a larger CAD system, where realistic woven fabric is required in a
variety of design applications.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of a CAD hardware system useful in the present
invention;
FIG. 2 is a flow chart illustrating the yarn design function of the present
invention;
FIG. 3 is a flow chart illustrating the spun and non-spun yarn design
functions of the present invention;
FIG. 4 is a flow chart illustrating the woven design function of the
present invention;
FIG. 5 is a flow chart illustrating the woven design from the basic weaves
function of the present invention;
FIG. 6 is a flow chart illustrating the woven design from the CD/DID
function of the present invention;
FIG. 7 is a flow chart illustrating the "store" function of the present
invention;
FIG. 8 is a flow chart illustrating the woven fabric function of the
present invention;
FIG. 9 is a flow chart illustrating the "browse thread" function of the
present invention;
FIG. 10 is a flow chart illustrating the "browse weave" function of the
present invention;
FIG. 11 is a flow chart illustrating the "store fabric layout" function of
the present invention;
FIG. 12 is a flow chart illustrating the "retrieve fabric layout" function
of the present invention;
FIG. 13 is a flow chart illustrating the "construct thread" function of the
present invention;
FIG. 14 is a flow chart illustrating the "construct fabric" function of the
present invention;
FIG. 15 is a flow chart illustrating the "execute" function of the present
invention;
FIG. 16 is a flow chart illustrating the "resize" function of the present
invention;
FIG. 17 is a flow chart illustrating the "new design" function of the
present invention;
FIG. 18 is a flow chart illustrating the "screen/output" function of the
present invention;
FIG. 19 is a flow chart illustrating the "scroll unit" function of the
present invention;
FIG. 20 is a flow chart illustrating the "group warp" and "group fill"
functions of the present invention;
FIG. 21 is a flow chart illustrating the "ungroup" function of the present
invention;
FIG. 22 is a flow chart illustrating the "delete" function of the present
invention;
FIG. 23 is a flow chart illustrating the "reverse CD/DID" function of the
present invention; and
FIGS. 24(a)-(24g) are diagrams of a woven fabric pattern being generated
with shading.
FIG. 24a illustrates a pair of one-pixel warp threads which, in FIG. 24b,
are woven with one-pixel fill threads. FIG. 24c illustrates a pair of
two-pixel warp threads which, in FIG. 24d, are woven with a pair of
two-pixel fill threads. FIG. 24e illustrates a pair of three-pixel warp
threads which, in FIG. 24f, are woven with a pair of three-pixel fill
threads. FIG. 24g illustrates the weave matrix applied in FIGS. 24b, 24d
and 24f.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Although the present invention finds immediate application in the apparel
and textile industries and the illustrated embodiment focuses on that
application, the present invention has potential application in a wide
range of design activities. In carrying out the invention, the illustrated
embodiment provides three sets of functions which may be executed in any
sequence. The functions include the design of yarns, design of weaves and
the design of woven fabrics. The preferred method is to utilize the yarn
design function to create a spun or non-spun yarn and the weave function
to design a desired weave pattern. Finally, the designed yarns and weaves
may be applied in the woven fabrics design function to obtain a realistic
visual image of the ultimate product utilizing design yarns and weaves.
The functions may be carried out in any sequence because default
parameters are provided for weaves and woven fabrics should the user not
design or specify a yarn or weave pattern. An effort has been made
throughout to provide a user-friendly system requiring minimal training.
A. SYSTEM HARDWARE
Computer system 30 includes input devices such as keyboard 32, video camera
34, mouse 36 and light pen 38 usable in combination with a graphic CRT 40
as locating instruments, and a two-dimensional drawing table 42. The
output of system 30 may be directed to a graphic CRT 44, which is a high
resolution 768 by 1024 pixels, video tape recorder 46, output camera 48
and printers 50 and 52. A central processing unit 54 of system 30 is
either 16-bit or 32-bit and includes two megabytes of main memory and 140
megabytes of secondary memory on hard disk 56. In the illustrated
embodiment, system 34 is a Silicone Graphics, Inc. IRIS workstation
utilizing UNIX operating system developed by American Telephone and
Telegraph, Inc. and a Silicone Graphics, Inc. standard graphic software
system.
B. DESCRIPTION OF THE SOFTWARE
1. Yarn Design
FIG. 2 illustrates the main flow chart for the yarn design function, and
outlines a function that allows the user to design and obtain a realistic
image of spun and non-spun yarn, from a menu displayed on the system. The
system, as a whole, is invoked from the exits to a standard
two-dimensional computer-aided design software system 100. Once invoked
from the two-dimensional CAD system 100, the function illustrated in FIG.
2 allows the user to select (102, 104, 106) from a menu anY of the
individual sub-functions 108-124 associated with yarn design. Referring to
the flow chart, note that there are nine sub-functions 108-124 that may be
invoked following a user-selection, plus an "exit" 125 function. Each of
the sub-functions 108-124 executes some portion of the initial yarn design
process. Once each of these sub-functions 108-124 finishes its task,
control is returned to the yarn design function illustrated in FIG. 2,
indicated by the labels R1 through R9. Control is then passed back to the
menu selection (US1) 132 so that the user may proceed to the next
sub-function. When the "exit" function is selected, this function
terminates and control passes back to the two-dimensional CAD system 100.
The "fiber size" function 112, "fiber space" function 114 and "S/Z twist"
function 116 allow the user to select, with a locating instrument such as
mouse 36 or light pen 38, the parameters required for designing a spun
yarn. When each of these functions is invoked, the system prompts the user
to enter the desired information. When the fiber space function 114 is
invoked, an area having a grid superimposed thereon is displayed on CRT 44
and may be enlarged or made smaller (126) by the use of an indicating
device which alters the size of the grid squares within the area which
designates, at grid nodal points, the location of the centers of the
fibers. Thus, enlarging the grid increases fiber spacing and vice versa.
When the fiber size function 112 is invoked, the user is prompted to
select (128) on the grid pattern the diameter of the cross section of the
threads that are desired. The "S/Z twist" function 116 allows the user to
set (130) a switch to effect counterclockwise (S) or clockwise (Z)
rotation of the fibers in the spun yarn.
When the user selects the "regular" sub-function 108 or the "novelty"
sub-function 110 (FIG. 3), the system retrieves (134) the fiber spacing
and size parameters entered by the user. If no parameters have been
entered by the user, default parameters are selected from memory. The
system lets the user select at 136, from a color palette that is an
accessory to the graphics software, the color to be applied to particular
fibers and the turns-per-inch parameter using locating instruments. The
system applies (138) shading to the cross-sectional image of each of the
fibers having an intensity variation within each fiber that is determined
as a function of the position of the portion within the fiber cross
section. The shading that is applied by the system to each fiber is a
sequence of laterally extending shading bands which increase in degree of
shading from the center of each fiber to its outer perimeter. Shading
bands toward the perimeter of the fiber are assigned a shading value in
the preferred embodiment that is approximately three times the intensity
of shading provided at the center of the fiber. It has been discovered
that this shading pattern provides the most realistic depiction of the
resulting yarn. It is believed that the adjacent fibers at the perimeter
of each fiber cause an increase in shadows cast on each fiber which
increases the amount of shading required at the perimeter. This effect is
not experienced at the interior of fibers.
After the spun-yarn sub-functions 108 and 110 have been performed, the
"execute 1" sub-function 120 is invoked by the user in order to spin the
yarn. The function retrieves (142) the turns-per-inch (TPI) specified by
the user in the "regular" 108 "novelty" 110 sub-functions and rotates
(144), while simultaneously longitudinally displacing the parameters of
the yarn cross section. The result of this operation on the fiber layout
parameters is dynamically displayed at 146 as the longitudinal side view
of the developing yarn. If the turns-per-inch parameter retrieved at 142
was specified through the "regular" 108 function, the rotation and
longitudinal displacement (144) is constant throughout the spinning
process. If, however, the turns-per-inch was specified through the
"novelty" sub-function 110, the TPI is randomly varied within a range less
than the TPI specified by the user, to create a novel thread having a
random twist pattern.
As an enlarged longitudinal side view is imaged while the yarn is spun
(144, 146), the system additionally displays in the preferred embodiment,
three longitudinal side view images of yarn designs (148) which are scaled
from the enlarged side view of the designed yarn by linear interpolation
to a one-pixel, two-pixel and three-pixel width image. The three images
are displayed 150 and may be stored in memory (151) for subsequent use by
invoking the "save" sub-function 124.
When the user selects the "non-spun" function 118, a longitudinal side view
image are displayed on CRT 44 and the user is prompted to use a locating
instrument, such as light pen 38, to specify (140) the fiber size by
choosing a "brush size" from the "paint box" standard function of the
graphic software and designing fiber strands on the yarn side view image
using a locating instrument and one of two hundred fifty-six colors
available from the "paint box" standard function. When the user is
satisfied with the non-spun yarn input, the "execute 2" function 122 is
invoked. The "execute 2" function 122 scales the enlarged longitudinal
side view at 148 by linear interpolation to produce one-pixel, two-pixel
and three-pixel yarn images of the user-designed non-spun yarn which are
displayed (150) and may be stored in memory (151) by invoking the "save"
function 124. The previously-described functions in the yarn design
function may be invoked to modify an existing yarn design following the
"execute 1" 120 or "execute 2" 122 sub-functions.
2. Weave Design
FIG. 4 illustrates the flow chart for the "woven design" function which
allows the user to develop a weave from known weave patterns, develop a
pattern from scratch by specifying the "chain-draft" and
"drawing-in-draft" sequences or by simulating a grid on a weave pattern
and using the reverse CD/DID function to determine the optimum CD/DID and
the CD/DID function to modify the design, from a menu displayed on the
screen. The function, as a whole, is invoked from the exits to standard
two-dimensional CAD software 100 and allows the user to select (152, 154,
156) from a menu of individual sub-functions 158-172 plus an "exit"
function 174. Each of the sub-functions 158-172 executes some part of the
"woven design" function and once each of these sub-functions finishes its
task, control is returned to the woven design function illustrated in FIG.
4, indicated by labels R10-R17. Control is then passed back to the menu
selection (US2) 176 so that the user may proceed to the next function.
FIG. 5 illustrates the flow chart for generating weave design from basic
weaves. When the user wishes to design a weave using a basic weave the
user selects the "plain" weave function 158, the "twill" weave function
160, the "rib" weave function 162, the "satin" weave function 164 or the
"basket" weave function 166. For each of the specified basic weaves, many
of the parameters are predefined and stored in the system by
initialization. When one of the basic weave functions 158 through 166 is
invoked, the user is prompted at 178 to provide parameters that are
required by the system to effect a weave design in the specified basic
weave function.
The user does not provide a parameter for plain weave since all of the data
required is initialized into the system. To create a twill, the user must
specify a desired twill angle and weave formula. The system will determine
the layout and up/over or over/up. To create a rib weave, the user must
enter a formula for the rib weave and the system derives the remaining
parameters. Likewise, in a satin or basket weave, the user specifies the
formula and the layout and up/over or over/up are initialized in the
system.
The function retrieves the weave formula (180) which is converted at 182
into a single dimension binary array. The function then determines at 188,
based on initialized standards, whether the selected basic weave is
vertically directed or horizontally directed. If the basic weave is
vertically directed, the first column of the weave matrix is built at 190
and the remaining columns are generated at 192 using the over/up algorithm
for that pattern. If it is determined at 188 that the particular pattern
is horizontally directed, the first row of the weave matrix is built at
196 and the remaining rows generated at 198 using the up/over algorithm.
With the weave matrix fully assembled (194) it is displayed (200) on CRT
44. A steering program directs control to R10 through R14 and back to the
menu selection (US2) 174 so that the user may proceed to the next
function.
The CD/DID function is provided to allow the user to design a weave other
than one of the five basic weaves. This function allows the user to
manipulate the "chain-draft" (CD), a sequence of lifting harnesses and the
"drawing-in-draft" (DID), a sequence of drawing warp threads through
harnesses. A woven fabric, which is formed by interlacing two sets of
threads or yarns, may be represented in diagram form with a binary
representation for vertical threads passing over horizontal threads and
the opposite condition. It is also known that weave chain-draft and
drawing-in-draft may be represented by binary matrices representing
multiplication of the chain-draft (CD) and the drawing-in-draft (DID). As
will be explained in more detail below, the present invention utilizes the
matrix attributes of a weave pattern to compress the data necessary to
specify the weave pattern in a bitwise operation prior to storage in
system memory to conserve memory space. It has been discovered that the
compression function, in addition to conserving memory, speeds the
execution of the program.
The flow chart for the CD/DID function is illustrated in FIG. 6. When the
user selects (168) the CD/DID function, a menu is displayed on the screen
providing the following choices:
______________________________________
Straight
Reverse
Point
Free Hand
Clear
Execute
Manual CD
______________________________________
When the user selects the "Straight" function 206, the "Reverse" function
208 or the "Point" function 210, the system lets the user (222) specify
the number of ends planned for the warp-end-to-harness drawing sequence. A
response to the message displays the corresponding portion of DID
automatically and the system builds or updates at 224 the weave matrix
which is displayed (226) on CRT 44. The user may then select (202, 203)
another CD/DID function. If the user selects the "Free Hand" function 212,
the system initiates a free hand drawing routine which allows the user
(228) to draw or modify a DID on the screen using a locating instrument,
such as light pen 38 or mouse 36. The system then builds or updates (224)
the weave matrix and displays (226) the result on CRT 44. When the user
selects the "Manual CD" function 214, the system lets the user (230)
select or modify the number of harnesses in the CD. If this represents a
change (232) the system redraws the grids at 234 and lets the user (236)
enter the CD using a locating instrument. The system then builds or
updates (238) the weaver matrix which is displayed at 240 on CRT 44.
The CD/DID function 168 additionally provides a "Clear" function 216 to
clear the CD or DID at 244 and an "Execute" function 218 to execute (246)
the CD/DID function. A "scroll" function 204 will laterally or vertically
adjust the displayed portion of the pattern on the screen.
The woven design function includes a reverse CD/DID function 168 (FIG. 4)
which provides a tool for the user to create a woven pattern design and
determine the optimum DID and CD for that design. The flow chart for the
reverse CD/DID function 170 is illustrated in FIG. 23. The function lets
the user select a color from the system color palette to designate the
"up" configuration at 402 and to design (404) the weave in the grid
pattern. At 406, the user utilizes the software "rubber band box" to
outline, and thereby designate, the portion of the free hand design for
which it is desired to have the DID and CD determined. The system
determines at 408 the optimum CD/DID corresponding to the user design. The
algorithm for determining an optimum CD/DID from a weave matrix is known
in the art and is disclosed in Lourie, Janice R. "Textile
Graphic/Computer-Aided" (1973), Chapter 9, pp. 171-188, which is
incorporated herein by reference.
The woven design function additionally provides a "store" function 172,
illustrated in FIG. 7, to store in memory, patterns developed by the weave
design function. Referring to FIG. 7, the function compresses (248) the
weave pattern matrix row-by-row using a bitwise operator. The system makes
use of the fact that the weave matrix is binary to store the matrix as
individual bits rather than as integers or bytes. In this manner, every
bit of each byte is utilized and a four-fold compression is realized. The
compressed matrix is stored (250) in the system's memory for subsequent
retrieval.
FIG. 8 illustrates the main flow chart for the "woven fabric" function and
outlines a function that allows the user to design and display the surface
image of a woven fabric. The function as a whole is invoked from the exits
to CAD system 100 and allows the user to select (252, 254, 256) from a
menu of individual sub-functions 258 to 288 | | |
