Clothes simulation method and apparatus

Abstract

A clothes simulation method and apparatus are disclosed. The clothes simulation method related to knitwear, according to one embodiment, may comprise the steps of: determining, on the basis of a twist speed parameter of a yarn corresponding to knitwear, the texture of a yarn corresponding to a plurality of plies of different colors; and generating rendering information of the knitwear by simulating a clothes pattern corresponding to the knitwear in which the yarn of the determined texture is arranged.

Description

Clothing simulation method and device

[0001] The following examples relate to a clothing simulation method and device, and more specifically, to a clothing simulation method and device for knitwear.

[0002] Clothing (or garments) appear three-dimensional when worn, but are actually closer to two-dimensional, consisting of pieces of fabric cut according to a two-dimensional pattern. Because the fabric used for clothing is flexible, its shape can change in various ways depending on the wearer's body shape and movements. Furthermore, fabrics can have various physical properties, such as strength, elasticity, and shrinkage, and differences in these properties can result in differences in the appearance and feel of clothing even within the same design. In the fashion industry, computer-based clothing simulation technology is widely used to develop actual clothing designs. Therefore, there is a growing need for the development of clothing simulation technology that can realistically represent clothing depending on the material used.

[0003] A method for simulating clothing for knitwear according to one embodiment includes the steps of: determining a texture of yarn corresponding to a plurality of plies of different colors based on a twist speed parameter of the yarn corresponding to the knitwear; and generating rendering information of the knitwear by simulating a clothing pattern corresponding to the knitwear in which yarns of the determined texture are arranged.

[0004] The number of times a particular fly appears in a given section of the yarn can be determined based on the above twist speed parameter.

[0005] The above twist speed parameter can be determined based on user input.

[0006] The step of determining the texture of the yarn may include the step of determining the texture of the yarn based on the twist speed parameter and the arc parameter of the yarn.

[0007] The above arc parameters may include random parameters indicating the twist start position of the yarn.

[0008] The arc parameters of different yarns arranged in the above garment pattern can be determined to different values.

[0009] The garment simulation method for the above knitwear may further include a step of mapping a vertex on a centerline of the yarn to a mesh of the garment pattern.

[0010] The step of determining the texture of the yarn may include the step of tessellating the centerline of the yarn into a cylinder mesh; and the step of determining the texture of the tessellated yarn corresponding to a plurality of plies of different colors based on the twist speed parameter.

[0011] The step of generating rendering information of the knitwear may include a step of generating rendering information of the knitwear by simulating the garment pattern in which the yarn is arranged based on a mapping relationship between the vertices and the mesh of the garment pattern.

[0012] The step of mapping the vertex to the mesh of the clothing pattern may include the step of obtaining a parameter corresponding to a deformation state of a material space corresponding to the clothing pattern; the step of interpolating a displacement calculated in advance based on the parameter corresponding to a deformation state sample to obtain a displacement of the vertex corresponding to the parameter; and the step of determining a position of the vertex corresponding to the deformation state in the material space based on the obtained displacement.

[0013] The step of generating rendering information of the knitwear may include the step of obtaining a position in world space corresponding to the knitwear of the vertex based on a position in the material space of the vertex corresponding to the deformation state; and the step of generating rendering information of the knitwear based on the obtained position in world space.

[0014] An electronic device according to one embodiment comprises at least one processor including processing circuitry; and a memory storing instructions, which when individually or collectively executed by the at least one processor cause the electronic device to perform the following operations: determining a texture of a yarn corresponding to a plurality of plies of different colors based on a twist rate parameter of the yarn corresponding to the knitwear; and generating rendering information of the knitwear by simulating a clothing pattern corresponding to the knitwear in which yarns of the determined texture are arranged.

[0015] The number of times a particular fly appears in a given section of the yarn can be determined based on the above twist speed parameter.

[0016] The operation of determining the texture of the yarn may include an operation of determining the texture of the yarn based on the twist speed parameter and the arc parameter of the yarn.

[0017] The above arc parameters may include random parameters indicating the twist start position of the yarn.

[0018] The arc parameters of different yarns arranged in the above garment pattern can be determined to different values.

[0019] The above instructions, when executed alone or jointly by the at least one processor, may further cause the electronic device to perform an operation of mapping a vertex on a centerline of the yarn to a mesh of the garment pattern.

[0020] The operation of determining the texture of the yarn may include an operation of tessellating the centerline of the yarn into a cylinder mesh; and an operation of determining the texture of the tessellated yarn corresponding to a plurality of plies of different colors based on the twist speed parameter.

[0021] The operation of generating rendering information of the knitwear may include an operation of generating rendering information of the knitwear by simulating the clothing pattern in which the yarn is arranged based on the mapping relationship between the vertices and the mesh of the clothing pattern.

[0022] Figure 1 is a flowchart of an operation of a clothing simulation method for knitwear according to one embodiment.

[0023] Figures 2a and 2b are drawings illustrating cross-sections of yarns in certain sections in which the twist speed parameters are set differently.

[0024] Figure 3 is a drawing for explaining the specific operation of a clothing simulation method according to one embodiment.

[0025] FIGS. 4A and 4B are drawings for explaining an operation of adjusting the position of a vertex of a yarn mapped to the outside of a garment pattern according to one embodiment.

[0026] FIGS. 5A to 5C are drawings illustrating the shape of a knitwear according to the direction information of a knit fabric according to one embodiment.

[0027] FIG. 6 is a drawing illustrating a user interface screen for setting physical property data of knitwear according to one embodiment.

[0028] FIGS. 7A to 12 are drawings for explaining a yarn-based knitting simulation method according to one embodiment.

[0029] Figure 13 is an exemplary diagram of the configuration of an electronic device according to one embodiment.

[0030] Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only and may be modified and implemented in various forms. Therefore, the actual implementation is not limited to the specific embodiments disclosed, and the scope of this specification includes modifications, equivalents, or alternatives within the technical concepts described in the embodiments.

[0031] In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of the noun corresponding to an item may include one or more of said items, unless the context clearly indicates otherwise.

[0032] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0033] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not limit the components in any other respect (e.g., importance or order). For example, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0034] When a component (e.g., a first component) is referred to as being “coupled” or “connected” to another component (e.g., a second component), with or without the terms “functionally” or “communicatively,” it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0035] Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "has" should be understood to indicate the presence of a described feature, number, step, operation, component, part, or combination thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0036] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0037] Hereinafter, embodiments will be described in detail with reference to the attached drawings. In the description with reference to the attached drawings, identical components are assigned the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted.

[0038] Figure 1 is a flowchart of an operation of a clothing simulation method for knitwear according to one embodiment.

[0039] The clothing simulation method for knitwear described in Fig. 1 can be performed on an electronic device. The specific hardware structure of the electronic device is described in detail below.

[0040] The garment simulation method for knitwear according to one embodiment may be briefly referred to as the 'method' or the 'garment simulation method' hereinafter.

[0041] Typically, a garment pattern corresponds to a paper template used to cut materials when making clothing. In this specification, a garment pattern may correspond to a two-dimensional flat garment pattern piece virtually created by a computer program. For example, garment patterns may be used to create a virtual garment that a user wishes to drape on a three-dimensional avatar. One or more garment patterns may be used to create a single garment.

[0042] According to an embodiment, a garment pattern may be a virtual two-dimensional garment pattern modeled as a sum of numerous polygonal meshes for simulating a three-dimensional virtual garment. Each vertex of the mesh is a point mass having a mass, and each edge of the mesh may be represented by springs having elasticity that connect the masses of the vertices. The garment pattern(s) may be modeled by, for example, a mass-spring model. Here, the springs may have respective resistance values ​​for, for example, stretch, shear, and bending depending on the properties of the fabric used. Each vertex may move under the action of an external force, such as gravity, and an internal force of stretch, shear, and bending. By calculating the external and internal forces applied to each vertex, the displacement and velocity of each vertex can be determined. Furthermore, the movement of the mesh vertices at each time step can be used to simulate the movement of a virtual garment. By applying two-dimensional virtual garment patterns made of triangular meshes to a three-dimensional object (e.g., an avatar), a natural-looking three-dimensional virtual garment based on the laws of physics can be created.

[0043] A method according to one embodiment may include simulating a virtual garment composed of a knitted fabric made by interweaving or crisscrossing yarns. The virtual garment composed of the knitted fabric may be referred to as knitwear.

[0044] A method for simulating clothing according to one embodiment may include a step (110) of determining a texture of a yarn corresponding to a plurality of plies of different colors based on a twist rate parameter of the yarn corresponding to the knitwear.

[0045] A yarn may contain one or more plies. For example, a yarn may be created by twisting one or more plies. The number of plies contained in a yarn determines its properties (e.g., density, feel, durability, flexibility, etc.). If a yarn contains multiple plies, the plies may be of different or identical colors.

[0046] The texture of a yarn is a visual characteristic of the surface of the yarn, and may include, for example, at least one of a color distribution of the yarn and a visual pattern of the yarn. The texture of the yarn may be determined based on a twist rate parameter of the yarn.

[0047] The twist rate (or twist ratio) parameter may correspond to a parameter indicating the number of times a ply is twisted per unit length of the yarn. The larger the value of the twist rate parameter, the greater the number of times a ply is twisted per unit length of the yarn. The number of times a specific ply appears in a given section of the yarn may be determined based on the twist rate parameter. For example, FIGS. 2A and 2B are diagrams illustrating cross-sections of a given section of yarn in which the twist rate parameters are set differently. The twist rate parameter of FIG. 2A has a larger value than the twist rate parameter of FIG. 2B. Referring to FIGS. 2A and 2B, the number of times a ply appears in a given section of the yarn may be different. For example, a given section of the yarn illustrated in FIG. 2A may have eight plys, and a given section of the yarn illustrated in FIG. 2B may have five plys. Referring to FIGS. 2a and 2b, a larger twist speed parameter may result in a greater number of flies appearing in a given section of the yarn.

[0048] For example, if a yarn includes a first color fly and a second color fly, the larger the twist speed parameter, the higher the probability that both the first color fly and the second color fly will appear in a certain section of the yarn. The smaller the twist speed parameter, the higher the probability that a section in which the first color fly does not appear or the second color fly does not appear may occur in the yarn. By setting the twist speed parameter, the color distribution of the fly of the yarn can be controlled. For example, since the rotation interval of fly of different colors in the yarn is determined by the value of the twist speed parameter, a melange texture of knitwear can be implemented by setting the twist speed parameter. Alternatively, a marled texture of knitwear can be implemented by setting the twist speed parameter.

[0049] According to one embodiment, the twist speed parameter may be determined based on physical property data of the knitwear. The physical property data of the knitwear is information indicating physical properties of the knitwear, and for example, the physical property data of the knitwear may include at least one of stitching type information of the knitwear, gauge information of the knitwear, direction information of the knit fabric, yarn thickness information, number of plies included in the yarn, color information of each ply included in the yarn, and information for randomizing the ply color distribution of the yarn. The information for randomizing the ply color distribution of the yarn may include information for determining the twist speed parameter of the yarn. The physical property data of the knitwear is described in detail below.

[0050] In one embodiment, the twist speed parameter may be determined based on user input. By adjusting the value of the twist speed parameter, the user can change the texture of the color distribution of the knitwear in which the yarns are placed.

[0051] According to one embodiment, the step (110) of determining the texture of the yarn may include a step of determining the texture of the yarn based on a twist speed parameter and an arc parameter of the yarn.

[0052] The arc parameter of a yarn is a parameter that represents a position on a curve defined along the centerline of the yarn, and may be a parameter determined by a real number within a specific range that represents, for example, a relative position from the starting point to the ending point of the yarn.

[0053] The arc parameter may include a random parameter indicating the starting position of the yarn. The twist of the ply(s) may start from the position of the center line of the yarn indicated by the arc parameter. The value of the arc parameter may be determined as a random value. The arc parameters of different yarns arranged in the garment pattern may be determined as different values. In other words, since the value of the arc parameter of each yarn is determined as a random value, the value of the arc parameter of each yarn arranged in the garment pattern(s) corresponding to the knitwear corresponds to a random value, and therefore the values ​​of the arc parameters of different yarns may be different or the same.

[0054] By randomly setting the value of the arc parameter of each yarn, noise (or irregularity) in the color distribution according to the different colored plies of the knit fabric can be generated. By randomly setting the value of the arc parameter of each yarn placed in the garment pattern, a melange texture of the knitwear can be implemented.

[0055] A method for simulating clothing according to an embodiment may include a step (120) of generating rendering information of a knitwear by simulating a clothing pattern corresponding to a knitwear in which yarns of a determined texture are arranged. The rendering information of the knitwear may be generated through simulation of the clothing pattern in which the yarns are arranged. The rendering information of the knitwear may include information for outputting the shape of a three-dimensional knitted garment in which the clothing pattern in which the yarns are arranged is worn on a three-dimensional object.

[0056] Figure 3 is a drawing for explaining the specific operation of a clothing simulation method according to one embodiment.

[0057] Referring to FIG. 3, a method for simulating clothing according to an embodiment may include a step (310) of mapping a vertex of a yarn to a mesh of a clothing pattern. The vertex of the yarn may include at least one vertex located on the centerline of the yarn. For example, the yarn may be modeled as edges connecting adjacent vertices located at regular intervals on the centerline of the yarn. For example, the yarn may be modeled as a discrete elastic rod. The modeling of the yarn will be described in detail below.

[0058] Mapping the vertices of a yarn to a mesh of a garment pattern may mean determining the position of each vertex of a yarn that constitutes a knitwear on the garment pattern. Mapping the vertices of a yarn to a mesh of a garment pattern may mean storing the position of each vertex of the yarn on the garment pattern as a positional relationship with the mesh of the garment pattern. Each vertex of the yarn may be positioned at the mapped position on the garment pattern. As described in detail below, when a garment including a garment pattern is simulated, the yarn may be positioned at the mapped position on the garment pattern and simulated based on the mesh.

[0059] According to one embodiment, the step (310) of mapping the vertices of the yarn to the mesh of the garment pattern may include the step of determining the position of the yarn on the material space corresponding to the deformation state. More specifically, the step (310) of mapping the vertices of the yarn to the mesh of the garment pattern may include the steps of: obtaining a parameter corresponding to the deformation state of the material space corresponding to the garment pattern; interpolating a displacement calculated in advance based on the parameter corresponding to the deformation state sample to obtain a displacement of the vertex corresponding to the parameter; and determining the position of the vertex corresponding to the deformation state on the material space based on the obtained displacement. Specific operations of the step of determining the position of the yarn on the material space corresponding to the deformation state will be described in detail below.

[0060] In one embodiment, the step (310) of mapping the vertices of the yarn to the mesh of the garment pattern may include the step of moving the vertices of the yarn located outside the garment pattern onto the boundary of the garment pattern. For example, in knitwear, the yarn may have a periodically repeating shape. When arranging the vertices of the yarn of the periodically repeating shape on the garment pattern, some of the vertices may be positioned outside the garment pattern.

[0061] For example, referring to FIG. 4a, when the yarn (401) has a periodically repeating shape, the first vertex (420) among the vertices at regular intervals on the center line of the yarn (401) may be placed outside the clothing pattern (410). The first vertex (420) placed outside the clothing pattern (410) may be moved to a position on the boundary line of the clothing pattern (410). For example, the position of the first vertex (420) may be changed to a position of the intersection of the edge (430) connected to the first vertex (420) and the boundary line of the clothing pattern. For example, referring to FIG. 4b, the position of the first vertex may be changed to a position of the intersection (440) of the edge connected to the first vertex and the boundary line of the clothing pattern.

[0062] Referring back to FIG. 3, according to one embodiment, the step (310) of mapping the vertices of the yarn to the mesh of the garment pattern may include a step of rotating the yarn based on the direction information of the knit fabric corresponding to the knitwear, and a step of mapping the vertices of the rotated yarn to the mesh of the garment pattern. For example, the direction information of the knit fabric may be included in the physical property data of the knitwear. The direction information of the knit fabric is information indicating the direction in which the yarn is arranged on the garment or garment pattern, and may include, for example, a specific angle, a direction vector, or a rotation value. For example, the direction information of the knit fabric may include information indicating the degree and / or direction of rotation of the yarn based on the default state of the yarn. The yarn may be rotated by the amount indicated by the direction information of the knit fabric in the default state and then arranged on the garment pattern. For example, if the direction information of the knit fabric indicates horizontal or 0 degrees, the yarn may be arranged on the garment pattern in the default state. For example, if the direction information of the knit fabric indicates vertical or 90 degrees, the yarn may be rotated 90 degrees from the default state and then arranged on the garment pattern.

[0063] For example, referring to FIGS. 5A to 5C, garments of knitted fabrics having different shapes may be rendered depending on the direction information of the knitted fabric. For example, the knitted fabric (510) of the garment illustrated in FIG. 5A may have a shape corresponding to the direction information of the knitted fabric (510) indicating the default state of the yarn or 0 degrees. Referring to FIG. 5B, when the direction information of the knitted fabric (520) indicates a rotation of 45 degrees, a knitted fabric (520) having a shape of the knitted fabric (510) of FIG. 5A rotated by 45 degrees may be rendered. Referring to FIG. 5C, when the direction information of the knitted fabric (530) indicates a rotation of 90 degrees, a knitted fabric (530) having a shape of the knitted fabric (510) of FIG. 5A rotated by 90 degrees may be rendered.

[0064] Referring back to FIG. 3, the step (320) of determining the texture of the yarn may correspond to the step (110) of FIG. 1. The step (320) of determining the texture of the yarn may include a step of determining the texture of the yarn based on ply data (321) and randomization setting data (322) of the ply color distribution. The ply data (321) may include physical property data of one or more plies included in the yarn. For example, the ply data (321) may include information on the number of plies included in the yarn and color information of each ply included in the yarn. For example, the ply data (321) may include a ply normal map. The ply normal map may correspond to a texture map for simulating surface curvature and / or unevenness of the yarn corresponding to the twist of the ply(s). The ply normal map may be data for realistically simulating the surface texture of the yarn generated by the twist of the ply. The fly color randomization setting data (322) is data for randomizing the fly color distribution of the yarn, and may include, for example, at least one of the twist speed parameter and the yarn arc parameter described above. As described above, the texture of the yarn may be determined based on at least one of the twist speed parameter and the yarn arc parameter.

[0065] According to one embodiment, the step (320) of determining the texture of the yarn may include the step of tessellating the centerline of the yarn into a cylinder mesh and the step of determining the texture of the tessellated yarn corresponding to a plurality of plies of different colors based on a twist speed parameter. The centerline of the yarn having no volume may be tessellated into a cylinder mesh having volume. The centerline of the yarn may be tessellated into a cylinder mesh having a predetermined thickness. As an example, the thickness of the cylinder mesh may be determined based on material data of the knitwear. The texture of the yarn determined in the step (110) may correspond to the texture of the yarn tessellated into the cylinder mesh. In other words, the step of tessellating the centerline of the yarn into the cylinder mesh may be performed after the step (310) of mapping the vertices of the yarn to the mesh of the garment pattern.

[0066] Step (330) of generating rendering information of knitwear may correspond to step (120) of FIG. 1. According to one embodiment, step (330) of generating rendering information of knitwear may include a step of generating rendering information of knitwear by simulating a garment pattern in which yarns are arranged based on a mapping relationship between vertices and a mesh of a garment pattern.

[0067] According to one embodiment, the step (330) of generating rendering information of a knitwear may include a step of simulating a yarn on a garment pattern in a world space corresponding to a deformation state. More specifically, the step of simulating a yarn on a garment pattern in a world space corresponding to a deformation state may include a step of obtaining a world space position corresponding to a knitwear of a yarn vertex based on a material space position of a vertex of a yarn corresponding to the deformation state, and a step of generating rendering information of the knitwear based on the obtained world space position. The world space may correspond to a space corresponding to a three-dimensional garment in which two-dimensional garment patterns are worn on a three-dimensional object. Two-dimensional mesh information corresponding to the material space of the garment pattern and three-dimensional mesh information corresponding to the world space may be obtained through garment simulation. Specific operations of the step of simulating a yarn on a garment pattern in a world space corresponding to a deformation state will be described in detail below.

[0068] FIG. 6 is a drawing illustrating a user interface screen for setting physical property data of knitwear according to one embodiment.

[0069] Referring to screen (600) of Fig. 6, the setting values ​​of the physical property data of the knitwear can be input through a user interface. For example, a user can input the setting values ​​of the physical property data of the knitwear through a user interface provided on a terminal.

[0070] For example, the physical properties of knitwear may include yarn thickness information. The yarn thickness value may be set through the yarn thickness input window (610) of the user interface. Knitwear including yarn having the set yarn thickness value may be simulated.

[0071] For example, the physical properties data of knitwear may include information on randomization settings for fly color distribution (e.g., ply randomization (Melange)). Whether or not to randomize fly color distribution can be set through the fly color distribution randomization setting window (620). If fly color distribution is set to be randomized, input of parameter values ​​for randomizing fly color distribution can be activated.

[0072] For example, when the fly color distribution is set to be randomized, a randomization factor input window (630) for determining a twist speed parameter may be activated. The value of the randomization factor may be input through the activated randomization factor input window (630). The value of the randomization factor may correspond to the twist speed parameter. For example, the larger the value of the randomization factor, the larger the value of the twist speed parameter may be determined.

[0073] For example, when the fly color distribution is set to be randomized, a seed position input window (640) for determining an arc parameter may be activated. A seed position value may be input through the activated seed position input window (640). The seed position may be a random parameter for determining the distribution of an arc parameter. The value of the arc parameter of each yarn may be randomly determined so that the larger the value of the seed position, the larger the distribution of the arc parameter value of each yarn. The larger the value of the seed position, the greater the randomness of the color distribution of the knit fabric.

[0074] For example, the material properties of a knitwear may include fly normal map data. A fly normal map for yarn simulation may be determined through the fly normal map input window (650). The knitwear may be simulated to include surface features indicated by the fly normal map input through the input window (650).

[0075] For example, the physical properties data of a knitwear may include information on the number of plies contained in the yarn. The number of plies contained in the yarn may be determined through the ply amount input window (660). The knitwear yarn may be simulated as a twisted form of the number of plies input through the ply amount input window (660).

[0076] For example, the physical property data of a knitwear may include information on the color of each ply included in the yarn. The ply color input window (670) may be generated in the same number as the number of plies input through the ply number input window (660). The color of each ply included in the yarn may be determined through the ply color input window (670). The yarn of the knitwear may be simulated as a twisted form of plies of the color input through the ply color input window (670).

[0077] For example, the physical properties data of knitwear may include knit fabric direction information (e.g., knit direction). The knit fabric direction may be determined through the knit fabric direction input window (680). The knitwear may be simulated with the knit fabric direction input through the input window (680).

[0078] In addition, the physical properties of knitwear may include information indicating the characteristics of the knitwear. For example, the physical properties of knitwear may include knit fabric type information (e.g., stitching type) and density information (e.g., gauge). The interface may include a knit fabric type setting window (691) and a density input window (692).

[0079] FIGS. 7A to 12 are drawings for explaining a yarn-based knitting simulation method according to one embodiment.

[0080] A yarn-based knitting simulation method according to one embodiment may be briefly referred to as a knitting simulation method hereinafter. The yarn-based knitting simulation method may correspond to steps (310) to (330) described above. More specifically, it may correspond to a step of determining a location of a yarn in a material space corresponding to the aforementioned deformation state and a step of simulating a yarn in a garment pattern in a world space corresponding to the deformation state.

[0081] A knit simulation method according to one embodiment may include a method for animating (or simulating) a yarn-level fabric (or knitted fabric) geometry on a deforming underlying mesh in a mechanics-aware fashion. The knit simulation method according to one embodiment may be a method for reproducing a phenomenon, such as the tightening effect of a knit loop when stretching, by interpolating a pre-computed yarn geometry using triangle strain. For example, referring to FIG. 7a, the yarn geometry of a knitted fabric before deformation is illustrated. When the knitted fabric is stretched, the simulation result of the knitted fabric without considering the yarn-level deformation may be as shown in FIG. 7b. Referring to FIG. 7b, the knitted fabric may be simulated such that the yarn stretching occurs uniformly due to the knitted fabric stretching regardless of the yarn geometry. Meanwhile, when the knitted fabric is stretched, the simulation result of the knitted fabric considering the yarn-level deformation may be as shown in FIG. 7c. In other words, the simulation results of Fig. 7c may be simulation results of a knitted fabric generated according to a knitting simulation method according to one embodiment. Referring to Fig. 7c, considering the geometric structure of the yarn, the knitted fabric can be simulated such that the loops of the yarn tighten when the knitted fabric is stretched.

[0082] According to one embodiment, a knitting simulation method may be a simulation method that adds yarn-level deformation to mesh-based cloth simulation. The behavior of a periodic yarn pattern may be pre-calculated based on large-scale deformation of an underlying cloth. The yarn pattern may refer to a garment pattern in which yarns are arranged. By interpolating the deformed yarn pattern at runtime based on the deformation state of the cloth mesh, a yarn-level geometric structure that is rearranged according to a yarn-level mechanism can be generated in real time.

[0083] A knitting simulation method according to one embodiment can receive an undeformed yarn pattern and a large-scale surface deformation as input for simulating a deformed geometric structure of a yarn pattern. The large-scale surface deformation can correspond to data encoded through a first fundamental form I and a second fundamental form II. As described in detail below, the large-scale surface deformation can be used to define boundary conditions and to optimize the elastostatic equilibrium configuration of the yarn pattern.

[0084] As mentioned above, a yarn can be modeled as a discrete elastic rod. A yarn can be represented as a linked list of vertices with positions x along the centerline. Each edge connecting the vertices can contain a twist angle θ and a reference director d1. Each vertex is associated with a four-dimensional vector q = (x T , θ) Tcan be expressed as, where θ corresponds to the twist angle of one adjacent edge. The reference direction vector d1 may not be included in the degrees of freedom. In other words, the reference direction vector d1 of the edge may not be included in the variables that are freely changed or calculated during the optimization or simulation process.

[0085] The kinematics of the positions of the vertices of the yarn during optimization can be expressed as in the following mathematical equations 1 and 2.

[0086]

[0087] In equations 1 and 2, X = (X1, X2, X3) T are the material-space coordinates of the undeformed yarn pattern, (X1, X2) are the orthogonal and periodic directions along the yarn pattern, and X3 represents the height coordinate. represents a large-scale deformation composed of the first basic shape I and the second basic shape II. The first basic shape can be simply referred to as I and the second basic shape as II. I encodes the in-plane deformation, and II encodes the bending deformation, respectively. From I and II, the midsurface And the normal n of the intermediate surface can be obtained, at this time, am.

[0088] Intermediate surface from I and II This can be defined from a least-squares perspective. To become can be calculated. For example, in the case of a single curvature, can be established. For the calculation, the rotation matrix R and the in-plane deformation matrix S, which indicate the curvature, can be calculated from the two basic shapes I and II. The 3Х2 matrix S can be calculated using the principal square root of I as shown in the following mathematical expression 3.

[0089]

[0090] To calculate the rotation matrix R, the derivative of the normal vector is as shown in Equation 4 below. n can be calculated.

[0091]

[0092] As in mathematical expression 5, a, b, and r can be calculated.

[0093]

[0094] As shown in mathematical expression 6, R(X1,X2) can be calculated.

[0095]

[0096] Poisson equation 2 = ·Discretize RS on a grid with natural boundary conditions. can be calculated. The constraint according to mathematical formula 7 is can be set to .

[0097] The yarn configuration that minimizes elastic energy can be calculated. The optimization variables are fluctuations that represent local displacements for large-scale deformation. and twist θ. Referring to Fig. 8, when the undeformed twist value is Θ, the concatenated coordinates are undeformed Q=(X T ,Θ) T , large-scale-deformed , optimized q=(x T , θ) T . Θ is assumed to be unaffected by large-scale mapping in the case of pure in-plane deformation. Bending deformation may also induce local twist depending on the orientation of the yarn with respect to the second fundamental shape II and the curvature direction.

[0098] For example, referring to FIG. 8, various large-scale surface deformations are applied to an undeformed yarn pattern Q (810) to produce a deformed (820) can be obtained. Using an optimization technique, the elastostatic rest shape q(830) is optimized for each deformation. q(830) is pulled back into the undeformed material space. (840) can be obtained. Displacement of Q(810) minus the initial state that is not deformed at (840) (850) can be obtained. (850) represents the local yarn level deformation according to the large-scale deformation state, From (850), a mapping relationship between large-scale deformation and the corresponding local yarn-level deformation can be constructed. As described below, corresponding to the sampled deformation state (hereinafter, deformation state sample) (850) can be pre-calculated and stored.

[0099] An optimization process according to one embodiment may include a nullspace in which yarns can slide. In other words, a periodic yarn curve x(s) expressed by a parameter s may be subject to a parametric shift. Even if you slide by s, the elastic energy E does not change. In other words, E(x(s)) = E(x(s + s)). Geometrically, the sliding motion can correspond to the tangential sliding of the yarn while maintaining the same periodic shape. In the optimizer, all sliding motion states are considered identical, and the actual result can be determined arbitrarily depending on the internal parameters of the numerical solver. The null space may not affect the homogenized energies by definition. Interpolation between two sliding motion states can produce completely different shapes of the yarn.

[0100] For example, the two curves (910, 930) illustrated in FIGS. 9A and 9C are yarns of the same shape, and when the starting position of the curve (910) of FIG. 9A is shifted by a certain distance, the curve (930) of FIG. 9C becomes. When the curve (910) illustrated in FIG. 9A and the curve (930) illustrated in FIG. 9C are interpolated, a new curve (920) that is very different from the curve (910) illustrated in FIG. 9A and the curve (930) illustrated in FIG. 9C can be generated, as illustrated in FIG. 9B. This is a phenomenon in which distortion occurs during interpolation because the expression method (or parameterization) is different even though the two curves (910, 930) illustrated in FIGS. 9A and 9C have the same shape mathematically.

[0101] Null spaces can introduce discreet interpolation artifacts, even for nearly identical deformation states. By adding constraints to the optimization process, parametric yarn sliding can be eliminated, effectively eliminating null spaces. More specifically, the constraints can be such that one vertex for each periodic yarn is fixed on the boundary of the garment pattern, as in Equation (7).

[0102]

[0103] In Equation 7, N is the undeformed normal vector to the boundary of the clothing pattern, which is N=(1,0). T or N=(0,1) T One of them is a sparse set of vertex constraints that can efficiently and effectively remove interpolation artifacts. The constraints allow physically realistic yarn shapes to be obtained for large-scale deformations described by the first and second basic shapes (I and II).

[0104] For example, if the tangential sliding phenomenon of the yarn is not considered when interpolating the geometric structure of the yarn, unrealistic distortion of the yarn may occur in the knitted fabric, as illustrated in Fig. 9d. For example, distortions such as the yarn colliding with itself or floating loops may occur. On the other hand, if a sliding constraint is introduced, a natural and physically reasonable interpolation result can be obtained, as illustrated in Fig. 9e.

[0105] The geometry of the yarn corresponding to representative deformation state samples can be precomputed, and the geometry of the yarn corresponding to the actual deformation state can be obtained by interpolating the geometry of the yarn corresponding to the precomputed deformation state samples at runtime. Since I and II are 2x2 symmetric tensors, directly parameterizing the deformation by I and II results in a six-dimensional function, which may be expensive to precompute and store, and to read at runtime. Therefore, the dimensionality of the deformation can be reduced by parameterizing the deformation with as few variables as possible.

[0106] Using in-plane strains, the first basic shape I can be reparameterized into a three-dimensional function as in Equation 8.

[0107]

[0108] II can be parameterized similarly to Equation 4 by introducing additional curvature variables and increasing the dimensionality of the dataset, but we show below that the bending deformation can be reasonably approximated by stretching variables alone. The entire large-scale deformation space is modeled by three variables s x , s a , s y can be sampled only on a regular 3D grid, which can significantly reduce memory and computational overhead. The deformation state samples can be sampled on a regular 3D grid.

[0109] At runtime, the geometry of the yarn obtained through interpolation can be mapped to a deformed mesh (e.g., a triangle mesh). The deformation of the mapped mesh can be naturally inherited by the geometry of the yarn. During the precomputation phase, the deformation state samples can be stored as material-space displacements.

[0110] The geometry of the optimized yarn q is the geometry of the yarn in the material space To pull back or convert to, large-scale transformation Modified material space coordinates that yield the desired world space transformation x when applied In other words, the geometry q of the optimized yarn is the geometry of the yarn in the material space. The problem with fullback is Satisfying This may correspond to the problem of finding .

[0111] Satisfying The problem of finding can be solved using Newton's method or Newton iteration. Function Newton's iteration method can be applied to this, where the gradient is is needed.

[0112] Mapping can be defined as in mathematical formula 9.

[0113]

[0114] In mathematical equation 9 is the deformed midsurface, and n is the normal vector of the midsurface.

[0115] The gradient can be defined as in mathematical equation 10.

[0116]

[0117] By definition can be expressed as in mathematical formula 11.

[0118]

[0119] and n can be calculated using Equation 4. Newton's iteration method can be expressed as Equation 12, and the initial value is a rest configuration , in other words, It could be.

[0120]

[0121] Within three iterations, the results obtained by Newton's iteration method can converge to a fraction of the yarn radius. The computational cost of Newton's iteration method is negligible compared to elastostatic optimization. For pure in-plane deformations, II = 0, so R = Id, In this case, the pullback becomes a simplified constant expression as in mathematical expression 13.

[0122]

[0123] After concatenating, Displacement by subtracting the initial material state from can be obtained. In other words, can be expressed as mathematical expression 14.

[0124]

[0125] In the rest pose, I=Id, II=0, and am.

[0126] For each vertex i of the yarn pattern, and various in-plane deformation state samples j: (s xj ,s aj ,s yj ) displacement of yarn in material space A database can be built. The database may correspond to a grid of example deformations, or The database can correspond to a 3D displacement texture for each yarn vertex. Interpolating the displacements of the deformation state samples yields a deformation s within a given plane. xj ,s aj ,s yj A yarn-level displacement map can be obtained. For strains sampled directly from the database, accurate yarn patterns can be reconstructed, and for intermediate strains of the sampled strains, approximate patterns can be generated.

[0127] A database of displacements of yarn patterns for various deformation states can be applied to tiled yarn patterns over an animated triangle mesh.

[0128] For example, referring to Fig. 10, Q(1010) is the undeformed coordinate (in material space), (1030) may correspond to the coordinate transformed by the local displacement, and q(1040) may correspond to the final world space coordinate. The geometry of the deformed yarn is obtained by applying the material displacement Q(1020) to the geometry of the undeformed yarn level tiled on the triangle mesh in the material space Q(1010). (1030) can be obtained. (1030) can be mapped to a mesh and transformed into a deformation q(1040) in world space.

[0129] As an example, Algorithm 1 illustrated in Fig. 11 is a mesh animation, yarn pattern and displacement In response to an input containing , the process of rendering q may be included.

[0130] An initial undeformed yarn mesh can be generated corresponding to an undeformed mesh (e.g., a triangle mesh) by precomputation. A 2D background grid can be generated on the UV coordinate system of the mesh, with cell sizes equal to the size of the periodic pattern. For example, the geometry of the yarn can be copied to all cells that overlap the undeformed mesh. For example, yarn vertices that do not exist within the mesh can be removed. For example, yarn pieces shorter than a user-specified length can be deleted for aesthetic purposes. The material space barycentric coordinates for each yarn vertex can be precomputed.

[0131] For each animation frame, discrete fundamental forms I and II for each mesh can be computed as shown in Equation 15 below.

[0132]

[0133] In Equation 15, F is the deformation gradient of the mesh, and Λ is the triangle-averaged shape operator. Using modified Shepard weights, I and II can be distributed to the vertices of the triangular mesh. Finally, by interpolating the I and II values ​​of the vertices of the triangular mesh where the yarn vertices are located, the actual deformation state of the yarn vertices can be estimated.

[0134] In one embodiment, the effect of bending behavior can be approximated by adding stretching and compression depending on the surface curvature.

[0135] Intermediate surface with normal vector n The full domain of the thin shell x expressed as is shown in the following mathematical expression 16.

[0136]

[0137] In mathematical expression 16, is the normal coordinate for the thickness H of the shell. At this time, the Cauchy-Green deformation tensor can be expressed as in mathematical equation 17 below.

[0138]

[0139] Equation (17) can be interpreted as the first basic shape I(h) that is quadratically dependent on h. The quadratic term in Equation (17) can generally be ignored. In addition, The basic shapes of and similarly As a result, the linearized expression is as shown in Equation 18.

[0140]

[0141] And, pre-computed data for the in-plane deformation s Using , the linearized bending model can be expressed as in mathematical equation 19 below.

[0142]

[0143] In other words, as explained through mathematical expression 18, the first basic shape I can be improved as in mathematical expression 20 below in a form that changes along the surface normal direction.

[0144]

[0145] As an example, referring to FIG. 12, the extruded volume (1220) around the middle surface (1210) bent by the bending model can be approximated by a linearized volume (1230) in which the upper portion of the middle surface (1210) is stretched and the lower portion is compressed.

[0146] Like most elastic materials, fabrics can buckle (or twist) out of plane when compressed. To prevent abnormal yarn deformation (buckling) due to compression, the eigenvalues ​​of the first fundamental shape I are used before querying the yarn displacements. can be clamped to a lower limit value, allowing buckling to be reduced in a user-adjustable manner.

[0147] For example, the minimum value for the eigenvalues ​​of I(Z) (e.g. 0.8) can be set. Eigenvalue < 1 can mean a compressed state. As I converges to the identity matrix (Id), Since converges to 0, the clamping technique only reduces local deformation, while the overall large-scale deformation along the triangle mesh can be maintained.

[0148] After clamping I, I is the strain s according to Equation 8 x , s a , s z can be converted to displacement of yarn (s x , s a , s z ) can be trilinear interpolation. The coordinates of the yarn in the transformed material space can be calculated as in mathematical equation 21 below.

[0149]

[0150] Strain outside the sampled range is (s x , s a , s z ) can be clamped to the nearest neighbors in the dataset. Similar to compressive clamping, constant extrapolation limits local deformations while still allowing large-scale deformations from the mesh embedding.

[0151] Equation 22 can be used to map the vertices of the yarn to world space x.

[0152]

[0153] Mathematical expression 22 is a mesh surface in world space. may correspond to extruding along the normal vector n. To avoid piecewise linear embedding artifacts, we use the Phong deformation and the normal vectors of the interpolated vertices. and shell volumes can be generated more smoothly.

[0154] The mapping of yarn twist is simply the updated twist value. can be processed by copying the edge normals can be co-transformed using an approximate mapping to the Jacobian of Equation 22.

[0155] Since the transformation of Yarn's vertices and their mapping into world space can be trivially parallelized, they can be implemented as GPU compute shaders. Interpolation of can be performed with a single 3D texture interpolation operation per vertex of the yarn.

[0156] The deformed yarn can be tessellated into a cylinder mesh in the geometry shader. Ply- and fiber-level details can be approximated by sequentially using twistable normal maps and ambient occlusion maps. Volume preservation can be approximated by locally rescaling the yarn radius during stretching.

[0157] Figure 13 is an exemplary diagram of the configuration of an electronic device according to one embodiment.

[0158] Referring to FIG. 13, an electronic device (1300) according to an embodiment may include a processor (1301), a memory (1303), and an input / output device (I / O) (1305). The electronic device (1300) according to an embodiment may include a device that performs the clothing simulation method for knitwear described above through FIGS. 1 to 12. For example, the electronic device (1300) may include at least one of a server and a user's terminal (e.g., a personal PC, a mobile phone, a tablet, a wearable device, etc.).

[0159] A processor (1301) according to one embodiment may include at least one processor including processing circuitry.

[0160] A processor (1301) according to an embodiment may perform at least one operation included in the clothing simulation method for knitwear described above through FIGS. 1 to 12. For example, the processor (1301) may perform at least one of an operation of determining a texture of yarn corresponding to a plurality of plies of different colors based on a twist speed parameter of a yarn corresponding to the knitwear, and an operation of generating rendering information of the knitwear by simulating a clothing pattern corresponding to the knitwear in which yarns of the determined texture are arranged.

[0161] The memory (1303) according to one embodiment may be a volatile memory or a non-volatile memory, and may store data related to the clothing simulation method for knitwear described above through FIGS. 1 to 12. For example, the memory (1003) may store data generated during the process of performing the clothing simulation method for knitwear described above through FIGS. 1 to 12, or data required to perform the clothing simulation method for knitwear described above through FIGS. 1 to 12.

[0162] According to one embodiment, the memory (1303) may not be a component of the electronic device (1300), but may be included in an external device accessible from the electronic device (1300). In this case, the electronic device (1300) may receive data stored in the memory (1303) included in the external device through a communication device, and may transmit data to be stored in the memory (1303).

[0163] According to one embodiment, the memory (1303) may store a program implementing the clothing simulation method for knitwear described above through FIGS. 1 to 12. The processor (1301) may execute the program stored in the memory (1303) and control the electronic device (1300). The code of the program executed by the processor (1301) may be stored in the memory (1303).

[0164] For example, the memory (1303) may store command(s). The command(s) stored in the memory (1303), when individually or collectively executed by the processor (1301), may cause the electronic device (1300) to perform an operation of determining a texture of yarn corresponding to a plurality of plies of different colors based on a twist speed parameter of yarn corresponding to the knitwear, and an operation of generating rendering information of the knitwear by simulating a clothing pattern corresponding to the knitwear on which yarns of the determined texture are arranged.

[0165] An input / output device (1305) according to one embodiment may include an input device and an output device. For example, user input regarding physical property data of a knitwear may be received through the input / output device (1305). For example, rendering information of a knitwear may be output through the input / output device (1305).

[0166] The electronic device (1300) according to one embodiment may further include other components not shown. For example, the electronic device (1300) may further include a communication device for communicating with other devices (e.g., a server, a terminal, a network, etc.). In addition, for example, the electronic device (1300) may further include other components such as a transceiver, various sensors, a database, etc.

[0167] The embodiments described above may be implemented using hardware components, software components, and / or a combination of hardware components and software components. For example, the devices, methods, and components described in the embodiments may be implemented using a general-purpose computer or a special-purpose computer, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable logic unit (PLU), a microprocessor, or any other device capable of executing instructions and responding to them. The processing device may execute an operating system (OS) and software applications running on the operating system. Furthermore, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For ease of understanding, the processing device is sometimes described as being used alone; however, one of ordinary skill in the art will recognize that the processing device may include multiple processing elements and / or multiple types of processing elements. For example, a processing unit may include multiple processors, or a processor and a controller. Other processing configurations, such as parallel processors, are also possible.

[0168] Software may include a computer program, code, instructions, or a combination of one or more of these, and may configure a processing device to perform a desired operation or may independently or collectively command the processing device. The software and / or data may be stored on any type of machine, component, physical device, virtual equipment, computer storage medium, or device for interpretation by the processing device or for providing instructions or data to the processing device. The software may also be distributed over networked computer systems and stored or executed in a distributed manner. The software and data may be stored on a computer-readable recording medium.

[0169] The method according to the embodiment may be implemented in the form of program commands that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may store program commands, data files, data structures, etc., alone or in combination, and the program commands recorded on the medium may be those specially designed and configured for the embodiment or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program commands, such as ROMs, RAMs, and flash memories. Examples of program commands include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0170] The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

[0171] Although the embodiments described above have been described with limited drawings, those skilled in the art will appreciate that various technical modifications and variations can be applied based on the described embodiments. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0172] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

In a clothing simulation method for knitwear, A step of determining the texture of the yarn corresponding to a plurality of plies of different colors based on the twist speed parameter of the yarn corresponding to the knitwear; and A step of generating rendering information of the knitwear by simulating a clothing pattern corresponding to the knitwear in which the yarn of the determined texture is arranged. including, method. In the first paragraph, The number of times a specific fly appears in a certain section of the yarn is determined based on the above twist speed parameter. method. In the first paragraph, The above twist speed parameter is determined based on the user's input. method. In the first paragraph, The step of determining the texture of the above yarn is A step of determining the texture of the yarn based on the twist speed parameter and the arc parameter of the yarn. including, method. In paragraph 4, The above arc parameters include random parameters that indicate the twist start position of the yarn, method. In paragraph 4, The arc parameters of different yarns placed in the above garment pattern are determined by different values. method. In the first paragraph, A step of mapping the vertices on the centerline of the above yarn to the mesh of the above clothing pattern. including more, method. In paragraph 7, The step of determining the texture of the above yarn is A step of tessellating the center line of the above yarn into a cylinder mesh; and A step of determining the texture of the tessellated yarn corresponding to a plurality of plies of different colors based on the twist speed parameter. including, method. In paragraph 8, The step of generating the rendering information of the above knitwear is A step of generating rendering information of the knitwear by simulating the clothing pattern in which the yarn is placed based on the mapping relationship between the vertex and the mesh of the clothing pattern. including, method. In paragraph 7, The step of mapping the above vertices to the mesh of the above clothing pattern is A step of obtaining parameters corresponding to a deformation state of a material space corresponding to the above clothing pattern; A step of interpolating a pre-calculated displacement based on a parameter corresponding to a deformation state sample to obtain a displacement of the vertex corresponding to the parameter; and A step of determining the position of the material space of the vertex corresponding to the deformation state based on the obtained displacement. including, method. In Article 10, The step of generating the rendering information of the above knitwear is A step of obtaining a position in world space corresponding to the knitwear of the vertex based on the position in the material space of the vertex corresponding to the deformation state; and A step of generating rendering information of the knitwear based on the position of the world space obtained above. including, method. A computer program stored on a computer-readable medium for executing the method of claim 1 in combination with hardware. In electronic devices, At least one processor comprising processing circuitry; and Memory that stores instructions Including, The above instructions, when individually or collectively executed by the at least one processor, cause the electronic device to: An operation of determining a texture of a yarn corresponding to a plurality of plies of different colors based on a twist speed parameter of the yarn corresponding to the knitwear; and An operation of generating rendering information of the knitwear by simulating a clothing pattern corresponding to the knitwear in which the yarn of the determined texture is arranged. to perform, Electronic devices. In Article 13, The number of times a specific fly appears in a certain section of the yarn is determined based on the above twist speed parameter. Electronic devices. In Article 13, The action that determines the texture of the above yarn is An operation of determining the texture of the yarn based on the twist speed parameter and the arc parameter of the yarn. including, Electronic devices. In Article 15, The above arc parameters include random parameters that indicate the twist start position of the yarn, Electronic devices. In Article 15, The arc parameters of different yarns placed in the above garment pattern are determined by different values. Electronic devices. In Article 13, The above instructions, when executed singly or jointly by the at least one processor, cause the electronic device to: An operation of mapping the vertices on the centerline of the above yarn to the mesh of the above clothing pattern. to do more, Electronic devices. In Article 18, The action that determines the texture of the above yarn is An operation of tessellating the center line of the above yarn into a cylinder mesh; and An operation of determining a texture of the tessellated yarn corresponding to a plurality of plies of different colors based on the above twist speed parameter. including, Electronic devices. In Article 19, The action of generating rendering information for the above knitwear is An operation of generating rendering information of the knitwear by simulating the clothing pattern in which the yarn is placed based on the mapping relationship between the vertex and the mesh of the clothing pattern. including, Electronic devices.

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