WO2007074728A1

WO2007074728A1 - Program for forming concave-convex texture and apparatus for forming concave-convex texture

Info

Publication number: WO2007074728A1
Application number: PCT/JP2006/325597
Authority: WO
Inventors: Kazunori Miyata; Koji Imao; Ryotaro Suzaki; Yoshitake Hatada; Yoshiyuki Sakaguchi
Original assignee: Digital Fashion Ltd.; Japan Advanced Institute Of Science And Technology
Priority date: 2005-12-26
Filing date: 2006-12-22
Publication date: 2007-07-05
Also published as: JPWO2007074728A1

Abstract

[PROBLEMS] To form a concave-convex texture which enables the realistic recreation of the characteristics of vital skin. In a virtual particle-locating part (102), a closed space (CS) is formed in a virtual three-dimensional space and multiple virtual particles (P) are located in this closed space. In a virtual particle-growing part (112), virtual particles (P) are grown in accordance with the growth pattern of vital skin cells. In an output computing part (111), the Van der Waals force (f), the force of gravity (FG) and the force of restriction (FS) applied on the virtual particles (P) are computed. In a position computing part (113), dynamic equations of the individual virtual particles (P) are solved to compute the position of each virtual particle. In a concave-convex texture forming part (104), the virtual particles (P) thus grown are projected on the bottom face (BS) and thus the concave-convex texture is formed.

Description

Specification

Uneven texture generation program and uneven texture generation apparatus

Technical field

The present invention relates to a computer graphics technique.

Background art

[0002] In recent years, as a pattern on the surface of a housing of a household electric appliance or the surface of an instrumental panel of an automobile, a wrinkle having a fine uneven shape force has been widely adopted. Among the various types of wrinkles, the ones that use the surface shape of the skin of animals such as reptiles as motifs are often used. On the other hand, designers of home appliances, etc., when forming a wrinkle on a housing of a home electric appliance, generally selects a predetermined wrinkle pattern medium force preference and applies it to the surface of the object to be designed Has been made. For this reason, if there is no wrinkle suitable for the design object, a new wrinkle needs to be generated.

[0003] On the other hand, in Non-Patent Document 1, the object surface is divided into pseudo Voronois using a particle model for the purpose of automatically generating a detailed shape of the object surface that affects the quality of CG images. Further, a technique for generating a detailed shape of an object surface by generating a subdivision curved surface with fractal noise for each polygon is disclosed.

[0004] However, when creating a new wrinkle with force, the designer creates it by adding a little arrangement to the existing wrinkle or arranging the pattern of the animal skin that actually exists. Cases were common, and there were certain limits to creating a grain that realistically represented the skin of an animal. In addition, the technique of Non-Patent Document 1 does not take into account the growth pattern of biological skin cells, and leaves room for further improvement in order to more realistically represent the characteristics of biological skin.

Non-Patent Document 1: Hirota-Tsubaki, Takayuki Ito, Kenji Shimada, “Generation of organic Textures with Controlled Anisotropy and Directionality via pacing rectangular” and EllipticalCells.IEEE CG & A Vol.23 No.3 pp.38-45,2003), IPSJ, 62nd National Convention Special Track (2) Proceedings, Special 2—53-60

Disclosure of the invention

[0005] An object of the present invention is to provide a concavo-convex texture generation program and a concavo-convex texture generation apparatus that realistically represent the characteristics of biological skin.

[0006] An uneven texture generation program according to the present invention is an uneven texture generation program for generating an uneven texture, which sets a closed space in a virtual three-dimensional space, and has a predetermined mass and a predetermined amount in the set closed space. Virtual particle placement means for placing a plurality of virtual particles having a size, and the growth pattern of biological skin cells, the number of virtual particles placed by the virtual particle placement means and the size of each virtual particle The interparticle force that calculates the interparticle force acting between the virtual particles growing means that grows each virtual particle in the closed space and the virtual particles determined based on the distance between the virtual particles A calculating means, position calculating means for calculating the position of each virtual particle by solving the equation of motion of each virtual particle when the interparticle force is applied to each virtual particle, Based on the position and size of the virtual particles, it is characterized in causing a computer to function as uneven texture generating means for generating an uneven texture.

[0007] The uneven texture generating device according to the present invention is an uneven texture generating device for generating an uneven texture, wherein a closed space is set in a virtual three-dimensional space, and a predetermined mass and in the set closed space are set. Virtual particle placement means for placing a plurality of virtual particles having a predetermined size; and a growth pattern of a skin cell of a living organism is simulated, and the number of virtual particles placed by the virtual particle placement means and each virtual particle Particles that increase the size and calculate the interparticle force acting between the virtual particles growing means for growing the virtual particles in the closed space and the virtual particles determined based on the distance between the virtual particles An intermediate force calculating means; a position calculating means for calculating the position of each virtual particle by solving a motion equation of each virtual particle when the interparticle force is applied to each virtual particle; and a virtual particle in a closed space. Based position and size of and is characterized in that it comprises a concave-convex texture generating means for generating an uneven texture.

[0008] According to these configurations, the number and size of the virtual particles in the closed space are increased according to the growth pattern of the skin cells of the organism. Each virtual particle in the virtual 3D space The interparticle force determined based on the distance between the virtual particles is acting, and the interparticle force acting on each virtual particle is calculated.

Further, the position of each virtual particle is calculated by solving the equation of motion of each virtual particle when an interparticle force is applied as an external force to each virtual particle. Then, an uneven texture is generated based on the position and size of the virtual particles in the closed space.

That is, when the closed space is assumed to be skin tissue, the size and number of virtual particles are determined according to the growth pattern of the skin cells contained in the skin tissue. Based on the position and size of the virtual particles, Since the concavo-convex texture is generated, it is possible to generate an concavo-convex texture that more realistically represents the characteristics of animal skin.

Brief Description of Drawings

FIG. 1 is a block diagram showing a hardware configuration of an uneven texture generating device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of the uneven texture generating device shown in FIG.

FIG. 3 is a flowchart showing the operation of the uneven texture generating apparatus.

FIG. 4 is a diagram showing a closed space generated in a virtual three-dimensional space.

[FIG. 5] (a) and (b) are diagrams showing examples of pattern textures.

[Fig. 6] A graph showing the van der Waals force in equation (1), where the vertical axis indicates f (w) and the horizontal axis indicates w.

FIG. 7 is a diagram showing van der Waals forces acting on virtual particles.

FIG. 8 is a diagram illustrating the constraint force acting on virtual particles.

[FIG. 9] A graph of the function shown in equation (4), where the vertical axis indicates the number of newly added virtual particles and the horizontal axis indicates the growth time.

FIG. 10 shows a closed space at the end of simulation.

FIG. 11 is a diagram illustrating a process for generating uneven texture.

FIG. 12 is a diagram showing an example of the uneven texture generated by the uneven texture generating apparatus. (A), (c), and (d) are generated without generating a potential field in a closed space. (B) shows the uneven texture generated when the potential field PF is generated in the closed space CS. FIG. 13 is a diagram showing a rendering result when a bumpy mapping of the uneven texture generated using the uneven texture generating device is performed on a car dashboard and a virtual three-dimensional model of the automobile interior is rendered. .

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a hardware configuration of the uneven texture generating device according to the embodiment of the present invention. The uneven texture generator is also configured as a normal computer isolator, input device 1, ROM (read only memory) 2, CPU (central processing unit) 3, RAM (random access memory) 4, external storage device 5, display A device 6 and a recording medium driving device 7 are provided. Each block is connected to an internal bus, and various data are input / output through this bus, and various processes are executed under the control of the CPU 3.

[0013] The input device 1 includes a keyboard, a mouse and the like, and is used by an operator to input various data, operation commands, and the like. ROM2 stores a system program such as BIOS (Basic Input / Output System). The external storage device 5 is configured with a hard disk drive or the like, and stores a predetermined OS (Operating System), an uneven texture generation program, and the like. The CPU 3 reads the concavo-convex texture generation program from the external storage device 5 and controls the operation of each block. RAM4 is used as a work area for CPU3.

The display device 6 is composed of a liquid crystal display device or the like, and displays various images under the control of the CPU 3. The recording medium driving device 7 includes a CD-ROM drive, a flexible disk drive, and the like.

[0015] Note that the uneven texture generation program is stored in a computer-readable recording medium 8 such as a CD-ROM and distributed to the factory. The user installs the uneven texture generation program in the computer by causing the recording medium driving device 7 to read the recording medium 8. You can also install the uneven texture generation program on a computer by storing the uneven texture generation program on a server on the Internet and downloading it from this Sano.

FIG. 2 is a functional block diagram of the uneven texture generating device shown in FIG. Irregularities The texture generation apparatus includes a processing unit 100, a storage unit 200, an input unit 300, and a display unit 400. The processing unit 100 includes functions of a potential field generation unit 101, a virtual particle arrangement unit 102, a simulation execution unit 103, an uneven texture generation unit 104, a rendering unit 105, and a display control unit 106. These functions are realized by the CPU3 executing the uneven texture generation program.

[0017] The potential field generation unit 101 reads a pattern texture selected by the user by operating the input unit 300 from the pattern texture storage unit 201, and generates a potential field in a closed space according to the read pattern texture. Here, the potential field is a virtual object that gives repulsive force to the virtual particles placed in the virtual 3D space. The pattern texture is image data representing the pattern that is the basis when the potential field is generated, and is two-dimensional and binary image data.

[0018] The virtual particle placement unit 102 sets a rectangular parallelepiped closed space in the virtual three-dimensional space. The virtual particle placement unit 102 reads the particle data stored in the particle data storage unit 202, performs a predetermined process on the read particle data in accordance with an operation command received by the input unit 300, and performs virtual processing. Deform the shape of the particles and place multiple virtual particles in the closed space.

[0019] The simulation execution unit 103 includes an external force calculation unit 111, a virtual particle growth unit 112, a position calculation unit 113, and a counter 114, and performs a simulation for growing virtual particles arranged in a closed space according to a growth pattern of skin cells. Execute.

The external force calculation unit 111 calculates an external force that acts on each virtual particle arranged in the closed space.

Here, the external force includes van der Waals force acting between molecules when one virtual particle is assumed to be one molecule, repulsive force receiving the potential field force described above, and gravity. Further, when the external force acting on a certain virtual particle exceeds a predetermined value, the external force calculation unit 111 erases the virtual particle from the closed space and kills the virtual particle.

[0021] The virtual particle growth unit 112 assumes one virtual particle as one skin cell, increases the number of each virtual particle according to the growth pattern of the skin cell, and increases the size of each virtual particle. Increase and grow each virtual particle. [0022] The position calculation unit 113 solves each virtual particle in a closed space by solving an equation of motion established for each virtual particle when the external force calculated by the external force calculation unit 111 is applied to each virtual particle. The position and velocity of each virtual particle are calculated. The counter 114 is a counter that measures the growth time of virtual particles. When the counter 114 increments the count value by 1, the virtual particle growth time elapses for a predetermined time.

The concavo-convex texture generation unit 104 obtains the distance between the virtual particle grown by the simulation execution unit 103 and the surface on one of the six surfaces constituting the closed space, and the virtual particle A projection surface onto the surface is obtained, and height data is given to the surface based on the obtained projection surface, the virtual particles, and the distance between the surfaces to generate an uneven texture. Further, the uneven texture generation unit 104 stores the uneven texture in the uneven texture storage unit 203 as necessary.

The rendering unit 105 reads the virtual 3D model stored in advance in the 3D model storage unit 204, and generates the uneven texture or the texture generated by the uneven texture generation unit 104 for the read virtual 3D model. Rendering is executed by using the uneven texture stored in the uneven texture storage unit 203.

[0025] The display control unit 106 causes the display unit 400 to display the virtual three-dimensional model rendered by the rendering unit 105. Further, the display control unit 106 reads out a plurality of pattern textures from the pattern texture storage unit 201 and causes the display unit 400 to display a list on the display unit 400 so that the user can select a pattern texture. Further, the display control unit 106 reads the particle data stored in the particle data storage unit 202 and causes the display unit 400 to display the virtual particles in order to allow the user to set the shape of the virtual particles. Furthermore, the display control unit 106 causes the display unit 400 to display the uneven texture generated by the uneven texture generation unit 104 or the uneven texture stored in the uneven texture storage unit 203.

The storage unit 200 includes the external storage device 5 shown in FIG. 1, and includes the functions of a pattern texture storage unit 201, a particle data storage unit 202, an uneven texture storage unit 203, and a 3D model storage unit 204. ing. These functions are realized by CPU3 executing the uneven texture generation program.

[0027] The pattern texture storage unit 201 serves as a basis when a potential field is generated. Image data representing the pattern is stored. The particle data storage unit 202 stores particle data representing the default shape of virtual particles. This particle data is 3D shape data. The particle data storage unit 202 stores mass data indicating the mass per unit volume of the virtual particles.

The uneven texture storage unit 203 stores one or more uneven textures generated by the uneven texture generation unit 104. The 3D model storage unit 204 stores a virtual 3D model created in advance by a user using known application software for generating a 3D model.

The input unit 300 includes the input device 1 shown in FIG. 1, and accepts various operation commands given by the user. The display unit 400 includes the display device 6 shown in FIG. 1, and displays various images under the control of the display control unit 106.

In the present embodiment, virtual particle arrangement unit 102 corresponds to an example of virtual particle arrangement means. The potential field generation unit 101 corresponds to an example of a virtual object generation unit. The external force calculation unit 111 corresponds to an example of an interparticle force calculation unit, a repulsive force calculation unit, and a virtual particle killing unit. Further, the virtual particle growth unit 112 corresponds to an example of virtual particle growth means. The position calculation unit 113 corresponds to an example of a position calculation unit. The potential field corresponds to an example of a virtual object.

Next, the operation of the uneven texture generating device will be described using the flowchart of FIG. First, the potential field generator 101 sets a rectangular parallelepiped closed space in the virtual three-dimensional space (step Sl). FIG. 4 is a diagram illustrating a closed space generated in the virtual three-dimensional space by the potential field generation unit 101. As shown in Fig. 4, X, y and z axes that are orthogonal to each other are set in the virtual three-dimensional space. Virtual gravity is acting in the z direction. Note that the virtual three-dimensional space may be represented by another coordinate system (for example, a polar coordinate system) instead of the orthogonal coordinate system of the X, y, and z axes.

[0032] The origin O, which is the intersection of the X, y, and z axes, is set at the lower left vertex of the closed space CS. Each side constituting the closed space CS is set in parallel with any side of the X, y, and z axes. Here, the length of each side constituting the closed space CS is a predetermined force potential field generation unit 101 in response to an operation command from the user received by the input unit 300. Accordingly, the length of the closed space cs may be changed as appropriate. In addition, the potential field generation unit 101 may adopt a shape other than a rectangular parallelepiped, for example, a sphere or a cube as the shape of the closed space CS.

In step S2 shown in FIG. 3, the potential field generation unit 101 generates a potential field according to the pattern texture selected by the user. Figures 5 (a) and 5 (b) show examples of pattern textures. As shown in Figs. 5 (a) and 5 (b), the pattern texture is a rectangular image in which long and narrow stripe patterns are represented. The pattern tissue shown in (a) is composed of a single line that snakes in the vertical direction and two lines of force that branch off. The pattern texture shown in (b) also consists of three muscles arranged so as to spread concentrically. Note that the pattern texture shown in FIGS. 5 (a) and 5 (b) is a binary image, and pixels constituting the streaks are represented by, for example, “1”, and pixels constituting the background other than the streaks are, for example, “0”. It is represented by

Note that the pattern textures shown in FIGS. 5 (a) and 5 (b) are merely examples, and patterns having other patterns may be employed. In addition, an image created by a user using drawing software may be adopted as a pattern texture.

[0035] The potential field generation unit 101 performs a filter process using a filter (for example, a Gaussian filter) for smoothing the image on the pattern texture selected by the user, and converts the pattern texture to, for example, each pattern texture. After the pixel is converted to a multi-value image represented by 256 gradations from 0 to 255, height data proportional to the number of gradations is given to each pixel. As a result, the pattern texture is converted into three-dimensional image data.

[0036] Next, the potential field generation unit 101 places the pattern texture converted into the three-dimensional image data on the inner side of the surface on the XY plane (hereinafter referred to as the bottom surface BS) of the closed space CS shown in FIG. For example, it is pasted by texture mapping. As a result, as shown in FIG. 4, a potential field PF composed of streaky ridges and a plane parallel to the XY plane is formed on the bottom surface BS.

[0037] In step S3 shown in FIG. 3, the virtual particle placement unit 102 reads shape data representing the default shape of the virtual particles P stored in the particle data storage unit 202, and closes the space according to the operation command of the user. Determine the number and position of virtual particles P to be placed on CS At the same time, the shape of the virtual particle P is deformed to arrange the virtual particle P in the closed space cs.

[0038] Here, the number of virtual particles P arranged in the closed space CS is determined based on the number of skin cells per unit volume immediately after the birth of an animal such as a human and the volume of the closed space CS, for example. Values can be adopted. However, this value is appropriately changed according to the operation command from the user.

[0039] The default shape of the virtual particle P is an ellipsoid in which the shorter of the three principal axes has the same length. Below, of the three main axes of the ellipsoid, one long main axis is called the major axis, and the remaining two main axes having the same length are called the minor axes. Predetermined default values are adopted for the lengths of the major axis and the minor axis of the ellipsoid. However, this default value is appropriately changed according to the operation command from the user. Further, a sphere may be adopted as the default shape of the virtual particle P. Also, the three main axes of the ellipsoid may have different lengths. Furthermore, an ellipsoid and a sphere may be mixed and arranged in the closed space.

[0040] The virtual particle arrangement unit 102 uses a predetermined probability density function (for example, normal distribution) or a default value of the long axis and the short axis, or the length of the long axis and the short axis changed by the user. Given random variations using random numbers, etc., the short axis and long axis length of each virtual particle P placed in the closed space CS are determined, and the shape of the virtual particle P is changed. When a sphere is used instead of the ellipsoid, the user can change the shape of the virtual particle P by setting the radius of the sphere.

[0041] Then, the virtual particle placement unit 102 is configured so that the virtual particles P do not overlap in the closed space CS, the bottom surface BS is regarded as the skin surface, and the z direction is regarded as the skin depth direction. Place virtual particles P according to the distribution of skin cells. FIG. 4 shows the closed space CS immediately after the virtual particle placement unit 102 places the virtual particles P in the closed space CS. As shown in FIG. 4, it can be seen that the closed space CS is arranged in such a manner that the size of the virtual particles P varies moderately and the virtual particles P do not overlap. Here, the virtual particle arrangement unit 102 may arrange the virtual particles P so that the directions of the major axes of the virtual particles P are parallel, or the virtual particles may be dispersed by appropriately varying the directions of the major axes. P can be placed.

In step S4 shown in FIG. 3, the counter 114 sets the count value to i = 0 and initializes the growth time of the virtual particles P. In step S5, the external force calculation unit 111 calculates the formula (1) Is used to calculate the van der Waals force acting on each virtual particle P.

f (w) = K / \ (5 / 4-w ³ -19 / 8-w ² +9/8) (1)

0 0

However,

f (w): Van der Waals force

K: Panel coefficient for determining attractive and repulsive forces between virtual particles

0

w = l / l

0

1: Distance between the center of virtual particle P and the center of virtual particle P

1 (P, P) = l / 2 (d (P) + d (P))

0 i j i j

P .: i-th virtual particle

P: jth virtual particle

d (P): Length of major axis of virtual particle P

[0043] FIG. 6 is a graph showing the van der Waals force of equation (1), where the vertical axis indicates f (w) and the horizontal axis indicates w. As shown in Fig. 6, f (w) takes a positive value when w is between 0 and 1. As shown in Fig. 7 (b), when virtual particles P and P overlap, virtual particle P

, P shows that repulsive force acts.

[0044] f (w) takes a value of 0 when w is 1. This shows that when the virtual particles P 1 and P 2 are in contact with each other, as shown in FIG. 7 (c), neither attractive nor repulsive force acts and it is stable.

j

[0045] Further, f (w) takes a negative value when w is in the range of 1 to about 1.3. As shown in FIG. 7 (a), when the virtual particles P 1 and P exist within a certain distance range, an attractive force acts on the virtual particles P 1 and P 2. Furthermore, f (w) takes a positive value when w is greater than 1.3. This indicates that the repulsive force acts when the virtual particles P 1 and P 2 are separated by a certain distance or more.

In step S 6 shown in FIG. 3, the external force calculation unit 111 calculates the constraint force FS of the potential field PF force acting on each virtual particle P. FIG. 8 is a diagram for explaining the constraint force FS acting on the virtual particle P. FIG. Note that the diagonal line shown in Fig. 8 shows the cross section of the potential field PF. The external force calculation unit 111 obtains a straight line L 1 that connects the center Ol of the virtual particle P and the potential field PF with the shortest distance, and obtains an intersection 02 between the straight line L 1 and the potential field PF. Next, the normal vector VI of the intersection 02 is obtained, and the obtained normal is obtained. The force obtained by multiplying the vector VI by a predetermined constant is obtained as the constraint force acting on the virtual particle 1 ^. Here, as the predetermined constant, for example, the mass of the virtual particle ^ can be adopted, and the magnitude of the gravitational acceleration can be adopted as the magnitude of the normal vector VI.

[0047] In the case of virtual particle P, a straight line connecting the center and potential field PF with the shortest distance

k

Since the intersection with the potential field PF exists on the XY plane, the virtual particle P

k receives the constraint force FS in the z direction. However, the virtual particle P is gravity in the z direction FG

Since k k k is received, the constraint force FS and gravity FG are canceled out, and the phantoms from other virtual particles P

k k

Only Ndelwarska f will be received. Virtual particle P is the same as virtual particle P

j k

Like, the restraining force FS and gravity FG are offset in the opposite direction, canceling out other virtual particles

j]

Only van derunore force f from P will be received.

[0048] Therefore, the virtual particle P located near the slope of the raised object on the potential field PF moves away from the raised object due to the constraint force FS. From the potential field PF.

[0049] In step S7 shown in FIG. 3, the external force calculation unit 111 calculates the mass of each virtual particle P and multiplies the calculated mass by the gravitational acceleration acting in the z direction, thereby acting on each virtual particle P. Find gravity FG. Here, the external force calculation unit 111 calculates the volume of the virtual particle P from the lengths of the major axis and the minor axis of the virtual particle P, and multiplies this volume by the mass data stored in the particle data storage unit 202, thereby Find the mass of particle P.

[0050] In step S8, the external force calculation unit 111 synthesizes the van der Waals force f that the virtual particle P receives also the other virtual particle P force, the constraint force FS received from the potential field PF, and the gravity FG. The external force Fo acting on the particle P is obtained, and it is determined whether the magnitude of the external force Fo exceeds a predetermined value. Then, the virtual particle P on which the external force Fo exceeding the predetermined value acts is erased from the closed space CS, and the virtual particle P is killed. The predetermined value is a value determined in advance based on the pressure that kills the actual skin cells.

[0051] In step S9, the counter 114 increments the count value i by 1, and advances the virtual particle growth time by a predetermined time.

[0052] In step S10, the position calculation unit 113 obtains the growth time t of the virtual particle P as the count value, and solves the equation of motion shown in Equation (2) using the Rungetta method, so that the growth time t Find the position and velocity of the virtual particle P. Note that the position calculator 113 The position and velocity of the virtual particle P may be calculated using the Euler method or the like instead of the clutter method.

[0053]

However,

m: Mass of virtual particle P

X: Position of virtual particle ^

c: Viscosity coefficient of closed space CS

t: Growth time

f: Van der Waals force acting on virtual particle P

FS: Restrictive force acting on virtual particle P

FG: Gravity

[0054] Here, x, f, FS, and FG are three-dimensional vectors made up of x, y, and z components, respectively.

The viscosity coefficient c is a value determined in advance based on the viscosity coefficient of the actual skin cell cytoplasm.

[0055] In step S11, the virtual particle growth unit 112 uses the function shown in Equation (3) indicating the actual increase in the size of the skin cell, and the long axis of the virtual particle P in the closed space CS and Increase the length of the minor axis and increase the virtual particle P.

[0056] _{CS = IS (1} — _e rt) (3) where

CS (current—size): Length of short axis and long axis of virtual particle P at growth time t

IS (initial—size): Length of short axis and long axis of virtual particle P when placed in closed space CS by virtual particle placement unit 102

r: Growth rate

t: Growth time

Here, the growth rate r is a value determined in advance based on the increase rate of the actual skin cell size. In step S12, the virtual particle growth unit 112 is represented by a sigmoid curve and uses the function shown in Equation (4) that represents the change over time in the actual number of skin cells. Thus, the number of newly added virtual particles P in the closed space cs (increase number of virtual particles P) is obtained, the position where the added virtual particles P are arranged is obtained, and a new virtual particle P is born in the closed space CS. Let

[0058] _{NOB = a} . _E -exp (-k (t-to)) ₍₄₎ However,

NOB (number— of— birth): Number of newly added virtual particles

a, k: constant

t: Growth time

tO: Inflection point of function shown in equation (4)

FIG. 9 is a graph of the function shown in Equation (4), where the vertical axis indicates the number of newly added virtual particles, and the horizontal axis indicates the growth time. As shown in Fig. 9, it can be seen that the number of newly added virtual particles gradually decreases as the growth time t increases. It can also be seen that an inflection point exists at the time when the growth time t is tO. This to is about half of the growth time until the number of virtual particles P increases to almost zero.

[0060] In step S13 shown in FIG. 3, the counter 114 determines whether or not the force at which the count value i has reached N (N is a positive integer) corresponding to the simulation end time. If it is determined that the value i becomes N (YES in S13), the process proceeds to step S14. On the other hand, if counter 114 determines that count value i is not N (NO in S13), it returns the process to step S5. Here, the value of N is appropriately changed according to the operation command from the user.

[0061] As described above, until the count value i becomes N, the processing from steps S5 to S13 is repeatedly executed, and the simulation for growing the virtual particles P in the closed space CS is executed. Figure 10 shows the closed space CS at the end of the simulation. As shown in Fig. 10, the size and power of the virtual particle P existing in the closed space CS are increased compared to Fig. 4 which shows the closed space CS at the start of the simulation. Therefore, you can grow!

[0062] In addition, the virtual particle P located near the slope of the protuberance of the potential field PF is Temporary field PF force is also constrained by FS.

[0063] In step S14 shown in FIG. 3, the concavo-convex texture generation unit 104 generates concavo-convex texture by projecting the virtual particles P onto the bottom surface BS. FIG. 11 is a diagram illustrating a process in which the uneven texture generation unit 104 generates an uneven texture. First, the concavo-convex texture generation unit 104 determines the distance H between the center Ol of the virtual particle P and the bottom surface BS as shown in (a). Next, as shown in (b), the virtual particle P is projected onto the bottom surface BS, and the projection surface S1 of the virtual particle P formed on the bottom surface BS is obtained. Then, as shown in (c), the projection surface S1 and the distance H are connected by a Gaussian curved surface, and height data is given to the projection surface S1, thereby generating an uneven texture. Here, an ellipsoid may be used instead of the Gaussian curved surface.

[0064] FIG. 12 is a diagram showing an example of the uneven texture generated by the uneven texture generating device, where (a), (c), and (d) generate a potential field PF in the closed space CS. The generated uneven texture is shown here, and (b) shows the generated uneven texture when the potential field PF is generated in the closed space CS.

[0065] It can be seen that the uneven texture shown in (a) has a larger variation in the size of the wrinkle diameter than the uneven texture shown in (c). This is due to the fact that the virtual particle placement unit 102 places the virtual particles P in the closed space CS by increasing the variation in the shape of the virtual particles P. It can also be seen that the uneven texture shown in (d) has a larger number of textures than the uneven texture shown in (a) to (c). This is because the virtual particle arrangement unit 102 increases the number of virtual particles P and arranges them in the closed space CS, or lengthens the simulation time.

[0066] In addition, the uneven texture shown in (b) forms the potential field PF generated based on the pattern texture shown on the left side in the closed space CS, and the virtual particles P grow! As shown on the right side of (b), avoiding the streak portion indicated by the pattern texture, it can be said that the wrinkles are formed.

[0067] Fig. 13 is a diagram showing the rendering results when rendering the virtual 3D model of the interior of a car by bump mapping the uneven texture generated using this uneven texture generator to a car dashboard. It is. As shown in Figure 13, this technology By using the 3D model generated by the steam generator and rendering, it can be seen that the texture of the dashboard surface is realistically reproduced.

[0068] As described above, according to the uneven texture generating device, the number and size of the virtual particles P arranged in the closed space CS are increased according to the growth pattern of the animal skin. Each virtual particle P is subjected to van der Waals force f, gravity FG, and constraint force FS, and each time each virtual particle P grows for a fixed time, these forces are calculated.

[0069] The motion equation of each virtual particle P when van der Waals force f, gravity FG, and constraint force FS are given to each virtual particle P is calculated using the Rungetta method. The position and velocity of each virtual particle P are calculated by solving each time it grows. Then, projections and depressions are generated by projecting the virtual particles P grown for a predetermined time onto the bottom surface BS.

[0070] Here, the force by which the virtual particle P is projected onto the bottom surface BS. Since this virtual particle P is grown according to the growth pattern of the skin of the living organism, the wrinkles formed on the surface of the bottom surface BS Skin features are incorporated. As a result, it is possible to generate an uneven texture that realistically represents the characteristics of the skin of an organism.

[0071] (Summary of the present invention)

(1) The uneven texture generation program according to the present invention is an uneven texture generation program for generating an uneven texture, which sets a closed space in a virtual three-dimensional space, and has a predetermined mass and a predetermined size in the set closed space. Virtual particle placement means for arranging a plurality of virtual particles having a thickness, and a growth pattern of a biological skin cell, and the number of virtual particles placed by the virtual particle placement means and the size of each virtual particle are determined. Virtual particle growth means for increasing each virtual particle in the closed space and an interparticle force for calculating the interparticle force acting between the virtual particles determined based on the distance between the virtual particles. A calculation means; a position calculation means for calculating the position of each virtual particle by solving the equation of motion of each virtual particle when the interparticle force acts on each virtual particle; and a virtual calculation in a closed space. The computer is caused to function as an uneven texture generating means for generating an uneven texture based on the position and size of the particles.

[0072] Further, the uneven texture generating device according to the present invention provides an uneven texture generating means for generating an uneven texture. A steer generation device, comprising: a virtual particle arrangement means for setting a closed space in a virtual three-dimensional space, and arranging a plurality of virtual particles having a predetermined mass and a predetermined size in the set closed space; Virtual particle growth means for simulating a growth pattern of skin cells, increasing the number of virtual particles arranged by the virtual particle arrangement means and the size of each virtual particle, and growing each virtual particle in the closed space And an interparticle force calculation means for calculating an interparticle force acting between the virtual particles determined based on the distance between the virtual particles, and an interparticle force when the interparticle force is applied to each virtual particle. Position calculating means for calculating the position of each virtual particle by solving the equation of motion of the virtual particle, and uneven texture generating means for generating an uneven texture based on the position and size of the virtual particle in the closed space. It is characterized by this.

[0073] According to these configurations, the number and size of the virtual particles in the closed space are increased according to the growth pattern of the skin cells of the organism. An interparticle force determined based on the distance between the virtual particles acts on each virtual particle existing in the virtual three-dimensional space, and the interparticle force acting on each virtual particle is calculated.

In addition, the position of each virtual particle is calculated by solving the equation of motion of each virtual particle when an interparticle force is applied to each virtual particle as an external force. Then, an uneven texture is generated based on the position and size of the virtual particles in the closed space.

[0076] (2) In the above configuration, the virtual object generating means for generating a virtual object that applies a repulsive force to each virtual particle in the closed space based on an operation command from a user, and the virtual particle The computer further functions as a repulsive force calculating means for calculating a repulsive force from the virtual object acting on each virtual particle every time it grows for a certain time, and the position calculating means includes the repulsive force calculated by the repulsive force calculating means and the particles It is preferable to solve the equation of motion by applying an interatomic force to each virtual particle.

[0077] According to this configuration, the virtual particles are moved away from the virtual object by the repulsive force from the virtual object. Since it moves so that it may force, a virtual particle can be disperse | distributed moderately.

[0078] (3) In the above configuration, the computer further functions as a texture storage unit that stores one or more types of textures representing a predetermined pattern, and the virtual object generation unit causes the texture storage unit to It is preferable to select one of the textures of the memorized texture according to the user's operation command and generate the virtual object based on the selected texture pattern.

[0079] According to this configuration, when the user selects a texture, based on the pattern represented by the texture,

Since the virtual object is generated and each virtual particle is moved by the repulsive force from the virtual object, it is possible to generate an uneven texture that represents the texture pattern selected by the user.

[0080] (4) Further, in the above configuration, the closed space is a hexahedron, and the uneven texture generating means obtains a distance between one surface of the hexahedron and each virtual particle, and each virtual particle. It is preferable to obtain a projection surface of the particle onto the surface, and provide height data to the surface based on the obtained distance and the projection surface to generate an uneven texture.

[0081] According to this configuration, an uneven texture is generated by projecting virtual particles onto one surface of the hexahedron. Therefore, when this surface is regarded as the skin surface of a living organism, the unevenness appearing on the skin surface is represented. Such uneven texture can be generated.

[0082] (5) Further, in the above configuration, the virtual particles in which the resultant force of the interparticle force calculated by the interparticle force calculation means and the repulsive force calculated by the repulsive force calculation means are larger than a predetermined value are closed. It is preferable to further provide virtual particle killing means for killing virtual particles by removing them from the space.

[0083] According to this configuration, it is possible to grow virtual particles that exist in a closed space in consideration of the characteristics of the skin of a living organism that die when subjected to a certain force, and to express the characteristics of the skin more realistically. Uneven texture can be generated.

[0084] (6) Further, in the above configuration, the virtual particle growth means uses a predetermined function indicating a temporal change in the number of the skin cells represented based on a sigmoid curve. Preferable to increase the number of particles.

[0085] According to this configuration, the change over time in the number of skin cells expressed based on the sigmoid curve Since the number of virtual particles is increased using a predetermined function indicating, the number of virtual particles can be increased according to the actual growth pattern of skin cells. As a result, it is possible to generate an uneven texture that more realistically represents skin characteristics.

[0086] (7) Further, in the above configuration, the virtual particle growth means uses a predetermined function indicating a change with time of the size of the skin cell expressed based on an exponential function. It is preferable to increase the amount of calories.

[0087] According to this configuration, since the size of the virtual particle is increased using the predetermined function indicating the change with time of the size of the skin cell expressed based on the exponential function, the size of the virtual particle Can be increased according to the actual skin cell growth pattern. As a result, it is possible to generate an uneven texture that more realistically represents skin characteristics.

(8) In the above configuration, it is preferable that the interparticle force calculation means calculates the interparticle force using a predetermined function indicating Van der Waals force.

According to this configuration, since the van der Waals force is applied to the virtual particles, it is possible to generate an uneven texture that more realistically represents the growth pattern of the skin cells.

Claims

The scope of the claims

[1] An uneven texture generating program for generating an uneven texture,

Virtual particle placement means for setting a closed space in a virtual three-dimensional space, and placing a plurality of virtual particles having a predetermined mass and a predetermined size in the set closed space;

Virtual particles for simulating a growth pattern of living skin cells, increasing the number of virtual particles arranged by the virtual particle arranging means and the size of each virtual particle, and growing each virtual particle in the closed space Growth means,

An interparticle force calculating means for calculating an interparticle force acting between the virtual particles determined based on the distance between the virtual particles;

Position calculating means for calculating the position of each virtual particle by solving a motion equation of each virtual particle when the interparticle force is applied to each virtual particle;

An uneven texture generating program that causes a computer to function as uneven texture generation means for generating an uneven texture based on the position and size of virtual particles in a closed space.

[2] Virtual object generating means for generating a virtual object that causes repulsive force on each virtual particle in the closed space based on an operation command of a user force;

Each time the virtual particles grow for a certain period of time, the computer is further functioned as a repulsive force calculating means for calculating a repulsive force from the virtual object acting on each virtual particle,

2. The uneven texture generating program according to claim 1, wherein the position calculating means solves the equation of motion by applying the repulsive force calculated by the repulsive force calculating means and the interparticle force to each virtual particle.

[3] As a texture storage means for storing one or more types of textures representing a predetermined pattern, the computer is further motivated,

The virtual object generation means selects any one of the textures stored in the texture storage means in accordance with a user power operation command, and generates the virtual object based on the selected texture pattern. The concave / convex texture generation program according to claim 2.

[4] The closed space is a hexahedron, The concavo-convex texture generating means obtains a distance between one surface of the hexahedron and each virtual particle, obtains a projection surface of each virtual particle onto the surface, and based on the obtained distance and the projection surface, 4. The uneven texture generating program according to claim 3, wherein height data is given to the surface to generate an uneven texture.

[5] By removing from the closed space virtual particles that the resultant force between the interparticle forces calculated by the interparticle force calculating means and the repulsive force calculated by the repulsive force calculating means is larger than a predetermined value, the virtual particles are removed. The uneven texture generating program according to claim 2, further causing a computer to function as virtual particle killing means for killing.

[6] The virtual particle growth means increases the number of virtual particles in the closed space using a predetermined function indicating a temporal change in the number of skin cells expressed based on a sigmoid curve. The uneven | corrugated texture production | generation program in any one of Claims 1-5.

[7] The virtual particle growth means increases the size of the virtual particles by using a predetermined function indicating a time-dependent change in the size of the skin cell expressed based on an exponential function! The program for generating uneven texture according to any one of claims 1 to 6.

[8] The uneven texture generation program according to any one of [1] to [7], wherein the interparticle force calculation means calculates the interparticle force using a predetermined function indicating van der Waals force. .

[9] An uneven texture generating device for generating an uneven texture,

An uneven surface that generates uneven texture based on the position and size of virtual particles in a closed space. The uneven | corrugated texture production | generation apparatus provided with a touch production | generation means.