This application is a 35 U.S.C. 371 National Phase Entry Application from PCT/JP2006/313780, filed Jul. 11, 2006, which claims the benefit of Japanese Patent Application No. 2005-219136 filed on Jul. 28, 2005, the disclosure of which is incorporated herein in its entirety by reference.
Not Applicable
Not Applicable
The present invention relates to an apparatus for performing a realistic loop simulation of a knitted fabric, a loop simulation method, and a loop simulation program.
The present applicant has proposed that a loop simulation be performed by determining the position of stitches using an empirical rule based on the type of stitch, connection relationships with adjacent stitches and so on (Japanese Unexamined Patent Application 2005-120501). However, this method is problematic in that:
The latter two problems can be expressed together as difficulty in simulating the three-dimensional structure of the knitted fabric.
The basic objects of the present invention are to minimize the use of empirical rules during a loop simulation while keeping the calculation load within a feasible range, and to express three-dimensional bulges, curls and so on of a knitted fabric.
A loop simulation apparatus according to the present invention is an apparatus for creating a knitted fabric image corresponding to design data of a knitted fabric such that a loop of each individual stitch is represented, characterized by: means for determining a distance deviation between a distance from each individual stitch on the knitted fabric image to an adjacent stitch and a standard value thereof as a tension; means for determining a deviation between an intersection angle between a line linking each individual stitch on the knitted fabric image to an adjacent stitch in a course direction and a line linking each individual stitch on the knitted fabric image to an adjacent stitch in a wale direction and a standard value thereof as a distortion angle; means for determining a deviation between an angle between two stitches adjacent to each individual stitch on the knitted fabric image in the wale direction, with respect to an axis expressing an orientation of each individual stitch on the knitted fabric image to an adjacent stitch in the course direction, and a standard value thereof as a bending angle about a course axis; means for determining a deviation between an angle between two stitches adjacent to each individual stitch on the knitted fabric image in the course direction, with respect to an axis expressing an orientation of each individual stitch on the knitted fabric image to an adjacent stitch in the wale direction, and a standard value thereof as a bending angle about a wale axis; and shifting means for shifting a position of each individual stitch on the knitted fabric image to reduce the tension, the distortion angle, the bending angle about the course axis, and the bending angle about the wale axis.
A loop simulation method according to the present invention is a method for creating a knitted fabric image corresponding to design data of a knitted fabric such that a loop of each individual stitch is represented, characterized by the steps of: determining a distance deviation between a distance from each individual stitch on the knitted fabric image to an adjacent stitch and a standard value thereof as a tension; determining a deviation between an intersection angle between a line linking each individual stitch on the knitted fabric image to an adjacent stitch in a course direction and a line linking each individual stitch on the knitted fabric image to an adjacent stitch in a wale direction and a standard value thereof as a distortion angle; determining a deviation between an angle between two stitches adjacent to each individual stitch on the knitted fabric image in the wale direction, with respect to an axis expressing an orientation of each individual stitch on the knitted fabric image to an adjacent stitch in the course direction, and a standard value thereof as a bending angle about a course axis; determining a deviation between an angle between two stitches adjacent to each individual stitch on the knitted fabric image in the course direction, with respect to an axis expressing an orientation of each individual stitch on the knitted fabric image to an adjacent stitch in the wale direction, and a standard value thereof as a bending angle about a wale axis; and shifting a position of each individual stitch on the knitted fabric image to reduce the tension, the distortion angle, the bending angle about the course axis, and the bending angle about the wale axis.
A loop simulation program according to the present invention is a program that can be executed by a computer, for creating a knitted fabric image corresponding to design data of a knitted fabric such that a loop of each individual stitch is represented, characterized by: a command for determining a distance deviation between a distance from each individual stitch on the knitted fabric image to an adjacent stitch and a standard value thereof as a tension; a command for determining a deviation between an intersection angle between a line linking each individual stitch on the knitted fabric image to an adjacent stitch in a course direction and a line linking each individual stitch on the knitted fabric image to an adjacent stitch in a wale direction and a standard value thereof as a distortion angle; a command for determining a deviation between an angle between two stitches adjacent to each individual stitch on the knitted fabric image in the wale direction, with respect to an axis expressing an orientation of each individual stitch on the knitted fabric image to an adjacent stitch in the course direction, and a standard value thereof as a bending angle about a course axis; a command for determining a deviation between an angle between two stitches adjacent to each individual stitch on the knitted fabric image in the course direction, with respect to an axis expressing an orientation of each individual stitch on the knitted fabric image to an adjacent stitch in the wale direction, and a standard value thereof as a bending angle about a wale axis; and a command for shifting a position of each individual stitch on the knitted fabric image to reduce the tension, the distortion angle, the bending angle about the course axis, and the bending angle about the wale axis.
Preferably, when shifting the stitch positions, each stitch is shifted according to a total shift amount obtained by adding together shift amounts relating respectively to the tension, the distortion angle, the bending angle about the course axis and the bending angle about the wale axis, which have been determined with respect to each stitch of the knitted fabric image.
In the following specification, unless any indication is given to the contrary, description relating to the loop simulation apparatus applies as is to the loop simulation method and loop simulation program, and description relating to the loop simulation method and loop simulation program applies as is to the loop simulation apparatus. Further, the subject knitted fabric may be a flat knitted fabric or a circular knitted fabric, and may be a piece of knitted fabric or a garment.
In the present invention, four factors determine the positions of the stitches, namely the tension, the distortion angle, the bending angle about the course axis and the bending angle about the wale axis. Note that the deviation from the standard values thereof is set as a difference, for example, but may be a ratio or the like. The tension is based on the deviation between the interval to an adjacent stitch and a standard value, and reflects a quality whereby a spring assumed to connect the stitches to each other attempts to return to its natural length (the standard value) after expanding or contracting from its natural length. The distortion angle reflects a quality whereby a stability value is allocated to the angle of each apex of a square formed by four stitches, for example, which are close to each other in the course direction and wale direction, and when the angle deviates from the stability value, it attempts to return to its original angle.
The bending angle about the course axis and the bending angle about the wale axis correspond to a quality whereby each stitch is not flat, and the two ends of the stitch attempt to move to the front and back of the knitted fabric about the center of the stitch. When the standard value of the bending angle is set at 180 degrees, the stitches attempt to converge in plane, and when the standard value is shifted from 180 degrees, the knitted fabric attempts to curl. By employing the bending angle about the course axis and the bending angle about the wale axis, the manner in which the knitted fabric deviates from the plane and deforms three-dimensionally can be simulated.
The four factors described above are based on various forces acting on the stitches and the force exerted by the stitches themselves as they attempt to deform three-dimensionally, and are not simply modelizations of an empirical rule. Hence, a loop simulation based on a well-founded model can be performed. Furthermore, to perform a simulation using the model described above, it is only necessary to determine the tension, the distortion angle, and the bending angles bout the course axis and wale axis, and these factors are all amounts that can be calculated simply. Hence, the time required for the simulation can be held within a practical range. In the present invention, a virtual knitted fabric or garment obtained through a loop simulation of knitting data can be viewed as if placed on a flat surface, for example, and therefore the knitted fabric or garment can be evaluated without test knitting.
The stitches may be shifted every time the tension, distortion angle, and bending angles about the course axis and wale axis are determined, but in so doing, the positional relationships between the stitches vary while the deviations are determined. Therefore, it is easier to determine the tension, distortion angle, and bending angles about the course axis and wale axis for all of the stitches, for example, and then perform processing to shift each stitch in accordance with a total shift amount obtained by adding together the respective shift amounts of the tension, distortion angle, and bending angles about the course axis and wale axis.
The reference symbols in the drawings are described as follows:
A best mode for carrying out the present invention will be described below.
8 denotes a display on which design data, loop simulation images of a knitted fabric and so on are displayed, while a printer 10 also outputs the knitted fabric design data, loop simulation images and so on. Note that a loop simulation image is an image simulating a virtual knitted fabric based on the design data of a knitted fabric such that individual loops (stitches) are represented realistically. The individual stitches have in-plane coordinates (x, y) and a coordinate (z coordinate) in an orthogonal direction to the in-plane coordinates, and the position of the stitch is represented by the base position of the stitch.
12 denotes a loop simulation program storage unit storing a program required to perform a loop simulation.
24 is a tension processor for outputting a difference between a distance from each individual stitch to four adjacent stitches in the wale direction and course direction, for example, and a default value, or in other words a standard value, as the tension. This tension value expresses tension generated when the distance between stitches deviates from the standard value. Note that in the following description, the term “adjacent stitches” signifies adjacent stitches in the wale direction and course direction, and when a right side stitch in the course direction or the like is being referred to, the terms “the adjacent right side stitch in the course direction” and so on will be used. In this embodiment, only the relationships between adjacent stitches are dealt with.
Further, the default value is determined here according to the loop length, and may signify the length of the thread per loop prior to stretching at the tension generated during knitting on a knitting machine, the length of the thread per loop during stretching at the tension of the knitting machine, or the length of the thread per loop following shrinkage when finishing is performed after the knitting is complete. The loop length may be assumed to vary in predetermined sections or in each individual stitch. The expansion and contraction of the thread at the tension of the knitting machine and during finishing depends on the material of the thread, and therefore the type of thread is also input into the user interface 6.
A distortion processor 26 determines the angle of a triangle constituted by a single stitch adjacent to each individual stitch in the wale direction, a single stitch adjacent to each individual stitch in the course direction, and the subject stitch, or in other words an intersection angle. When the course direction and wale direction form a right angle, this angle, i.e. the intersection angle, should be 90 degrees. A standard value (default value) of the intersection angle is set at 90 degrees unless input indicating otherwise is received through the user interface 6. The difference between the intersection angle and the standard value is the distortion angle, and each individual stitch has four intersection angles. Here, however, the intersection angle between the left side adjacent stitch in the course direction and one of the upper and lower stitches in the wale direction and the intersection angle between the right side stitch in the course direction and the aforementioned stitch in the wale direction are used, and therefore two intersection angles are determined for each individual stitch. A force for aligning the intersection angle with the default value acts on the adjacent stitch in accordance with the difference between the intersection angle and the default value, or in other words the distortion angle. The distortion angle expresses this force.
A course direction bending processor 28 is based on the fact that, with respect to the axis of the course direction, the two adjacent stitches in the wale direction become stable at a predetermined angle. Further, a wale direction bending processor 30 is based on the fact that, with respect to the axis of the wale direction, the two adjacent stitches in the course direction become stable at a predetermined angle. These processors 28, 30 will be described in detail below with reference to
A synthesizer 32 shifts the individual stitches over the knitted fabric data. The positions of the stitches may be moved every time the tension, the distortion angle, and the bending angles about the course axis and wale axis are determined, but in this embodiment, the tension, the distortion angle and the bending angles about the course axis and wale axis are calculated in relation to all of the stitches. A weighting is then applied to these elements such that when the weighting of the tension is 1, for example, the other weightings are between approximately 1 and 0.1. The weighting is multiplied by each element, such as the tension, and the result is set as an individual shift amount. In the case of the tension, for example, four adjacent stitches exist as standard in the course direction and wale direction, and therefore four tension values are obtained. Hence, by multiplying a weighting by these values and then adding the results together, a total shift amount is generated in relation to the tension. In this manner, a total shift amount relating to the four factors described above is determined. The other shift amounts, such as the distortion angle, likewise include a plurality of elements per shift amount.
The total shift amount is determined for each individual stitch, whereupon the stitches are shifted. The shift amount includes the amount by which the subject stitch is moved and the amount by which adjacent stitches are moved. Note that if an attempt is made to shift a single stitch and its adjacent stitches every time the total shift amount relating to the stitch is determined and then determine the shift amount of the next stitch, calculation of the shift amount becomes unstable.
A collision determination unit 34 detects collisions between stitches such that when the positions of two stitches match in a horizontal plane, for example, and there is no difference in the diameter part of the thread on the z coordinate of the stitches, it is determined that a collision has occurred. When the collision determination unit 34 detects a collision, the shift amount is changed to a position at which the collision does not occur.
A convergence determination unit 36 determines whether or not the shift amount has converged to 0 or to a predetermined value or less when a process extending from calculation of the shift amount to correction of the shift amount through collision determination has been executed repeatedly. When the shift amount has converged or the number of processes has reached an upper limit, the convergence determination unit 36 terminates stitch position shifting, assuming that stable knitted fabric data have been obtained in relation to the four factors described above through simulation.
A thread stripe information creation unit 38 determines the thread stripe, i.e. the position of the thread or the flow of the thread, such that the determined stitch positions are connected. As a result, the thread position is determined. On the basis of this position, a rendering unit 40 implements rendering, and thus a loop simulation image is obtained.
A synthesis command 62 is a command for executing the processing of the synthesizer 32. A collision determination command 64 is a command for executing the processing of the collision determination unit 34. A convergence determination command 66 is a command for executing the processing of the convergence determination unit 36. A thread stripe information creation command 68 is a command for executing the processing of the thread stripe information creation unit 38. A rendering command 70 is a command for executing the processing of the rendering unit 40.
Respective shift amounts, i.e. shift vectors or correction vectors, are determined in relation to the tension, distortion angle and bending angles and gradually added to a shift vector array. This array is a data array, the individual elements of which are the respective shift amounts of the tension, distortion angle, wale direction bending angle and course direction bending angle of each stitch.
In parameter lists 80 to 83 shown in
The shift amounts (shift vectors) of each of the tension, the distortion angle, the wale direction bending angle and the course direction bending angle are extracted from the array, multiplied by the weighting of each factor, and added together to produce a synthesized shift vector. Next, the presence of a collision between the subject stitch (each stitch) and the other stitches when each stitch is moved by the synthesized shift vector is determined, and when a collision occurs, the synthesized vector is corrected so as to avoid the collision.
The positions of all of the stitches, i.e. all of the stitches of the knitted fabric, are then shifted in accordance with the synthesized vector. When the stitch shift amount of a single process converges to substantially zero, thread stripe information is created using the position and attributes of the stitch and the position of adjacent stitches, whereupon rendering is performed to create a realistic loop simulation image.
A similar problem occurs as curling at the top and bottom of the knitted fabric, and when a plain face stitch is observed from the side, the two ends of the stitch are pulled forward and the center of the stitch is pulled backward. The upper end and lower end of the knitted fabric are free, and therefore forward direction curling occurs in these positions. This phenomenon is simulated by course direction bending processing, whereby bending displacement of the knitted fabric relating to the course direction axis is simulated.
In
A pattern can be made to stand out by varying the size of each stitch using black and white thread. In this embodiment, a simulation can be performed such that the stitch size is modified according to the loop length of each stitch, and therefore this type of pattern can also be simulated.
In a simulation image of a glove, which relates to a tubular knitted fabric having a back side and a palm side, the default value of the course direction and wale direction bending angles is set at 120 degrees such that the bend at the ends of the tubular glove are represented naturally.
In one embodiment, a simulation of a knitting pattern for a pin tuck pattern can be produced where the three-dimensional deformation of the knitted fabric caused by the pin tuck is represented. The pin tuck is represented with a tendency to be pushed toward the lower side of the knitted fabric, but a simulation that emphasizes the bulging and projection of the pin tuck from the knitted fabric may also be performed.
Number | Date | Country | Kind |
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2005-219136 | Jul 2005 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2006/013780 | 7/11/2006 | WO | 00 | 1/25/2008 |
Publishing Document | Publishing Date | Country | Kind |
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WO2007/013296 | 2/1/2007 | WO | A |
Number | Name | Date | Kind |
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6880367 | Suzuki | Apr 2005 | B2 |
7386360 | Noriyuki | Jun 2008 | B2 |
20050039495 | Suzuki | Feb 2005 | A1 |
20070088453 | Noriyuki | Apr 2007 | A1 |
Number | Date | Country |
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09-212664 | Aug 1997 | JP |
WO 2005038117 | Apr 2005 | WO |
Number | Date | Country | |
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20100145495 A1 | Jun 2010 | US |