JP2007257079A - Texture generation program, texture generation device, and texture generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a three-dimensional texture in which a material texture to be simulated is realistically reproduced without modeling. <P>SOLUTION: A texture generation device comprises: a specular direction calculation part 11 for irradiating respective sample points comprising a texture with light from a virtual light source, and for finding a specular direction of the light at the respective sample points by using BRDF; a normal vector calculation part 12 for calculating a normal vector at the respective sample points from the specular direction and an incident direction of the light from the virtual light source; and an irregularity information calculation part 13 for calculating irregularity data at the respective sample points based on the calculated normal vector. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a computer graphics technique, and more particularly to a technique for generating a three-dimensional texture representing unevenness information on an object surface.

  In recent years, there has been a growing need in the automotive industry to virtually design by computer simulation without evaluating a prototype, evaluate the designed product, and lead to manufacturing.

  In the field of automobiles, development costs for materials such as fabrics used for car seats after engines are increased. Since it is difficult to judge whether the design of the material is good or bad unless it is actually applied to the interior, various attempts have been made to reproduce the material applied to the interior by computer simulation.

When a real interior is reproduced by a computer, a three-dimensional texture that is expressed in a fine scale that cannot be visually recognized by the naked eye on the surface roughness information of the material used in the interior is modeled, and this three-dimensional texture is used to create a virtual This is done by rendering a 3D model. Note that Patent Document 1 is known as a technique related to the present invention.
JP 2005-115645 A

  However, in the above conventional method, it is necessary to model a three-dimensional texture of the scale as described above, and this modeling has a problem that it takes a lot of time because it is necessary to input a huge amount of data. . In addition, in order to judge whether the material design is good or bad, it is necessary to observe the modeled three-dimensional texture in a macro manner, and for that purpose, it is necessary to render a virtual three-dimensional model using the modeled three-dimensional texture. . When changing the design of the material, it is necessary to correct the 3D texture. Therefore, until the desired design is obtained, the 3D texture must be corrected and the corrected 3D texture rendered repeatedly. However, there was a problem that it took a lot of time and labor.

  An object of the present invention is to provide a texture generation program, a texture generation device, and a texture generation apparatus that generate a three-dimensional texture that allows a user to model a three-dimensional texture of an object to be simulated without causing the user to model the texture. And providing a texture generation method.

  A texture generation program according to the present invention is a texture generation program for generating a three-dimensional texture representing unevenness information of an object surface, and includes an acquisition unit that acquires a bidirectional reflectance distribution function of the object, and the acquisition unit. The computer is caused to function as generation means for generating a three-dimensional texture based on the obtained bidirectional reflectance distribution function.

Further, in the above configuration, the generating unit arranges a plurality of sample points in a virtual three-dimensional space, and changes the regular reflection direction of light emitted from the virtual light source to each of the arranged sample points. A normal vector of each sample point is calculated from a specular reflection direction calculation means calculated using a rate distribution function, and a regular reflection direction of light calculated by the specular reflection direction calculation means and an incident direction of light from a virtual light source. It is preferable to include a normal vector calculating unit that calculates the unevenness information of each sample point based on the normal vector calculated by the normal vector calculating unit.

  Further, it is preferable that the regular reflection direction calculation means sets the direction of the line of sight to the direction of the virtual light source that outputs the maximum reflectance of the bidirectional reflectance distribution function as the regular reflection direction.

  Further, in the above configuration, the normal vector calculation means corrects the normal vector at each sample point so that the direction of the normal vector follows a predetermined probability density function, and the unevenness information calculation means includes the probability density function. It is preferable to calculate the unevenness information of each sample point using the normal vector corrected by the above.

  In the above configuration, the unevenness information calculating means includes a three-dimensional texture composed of unevenness information calculated using normal vectors not corrected by the probability density function, and a method corrected by the probability density function. Calculating a three-dimensional texture composed of uneven information calculated using a line vector, presenting a plurality of three-dimensional textures calculated by the uneven information calculating means to the user, and any one of the presented three-dimensional textures It is preferable to further cause the computer to function as a presentation unit that receives a command from a user who selects the three-dimensional texture.

  In the above configuration, it is preferable that the computer further function as offset setting means for setting an offset value in the height direction for each sample point.

  The texture generation device according to the present invention is a texture generation device for generating a three-dimensional texture representing the structure of an object surface, and acquires the bidirectional reflectance distribution function of the object, and the acquisition unit acquires the bidirectional reflectance distribution function. And generating means for generating a three-dimensional texture based on the bidirectional reflectance distribution function.

  The texture generation method according to the present invention is a texture generation method in which a computer generates a three-dimensional texture representing the structure of an object surface, the acquisition step acquiring a bidirectional reflectance distribution function of the object, and the acquisition step And a generating step for generating a three-dimensional texture based on the bidirectional reflectance distribution function.

  According to the first aspect of the present invention, a three-dimensional texture representing the unevenness information of the object surface is generated based on the bidirectional reflectance distribution function of the object. Therefore, the user can obtain a three-dimensional texture representing the unevenness information on the surface of the object only by giving a bidirectional reflectance distribution function of the object to be simulated without modeling the three-dimensional texture. In addition, since a three-dimensional texture corresponding to the object to be simulated is generated, there is no need to modify the three-dimensional texture so that the object has a desired design, and it can be performed quickly without performing complicated work. A three-dimensional texture can be obtained. By rendering the obtained 3D texture to a virtual 3D model, the interior of the car seat can be reproduced realistically, and the interior design can be evaluated without developing an actual prototype. Development costs can be reduced.

According to the second aspect of the present invention, using the bidirectional reflectance distribution function for the object, the regular reflection direction for each sample point arranged in the virtual three-dimensional space is calculated, and the calculated regular reflection direction; The normal vector of the surface including each sample point is calculated from the incident direction of light from the virtual light source, and the unevenness information of each sample point is calculated based on the calculated normal vector to generate a three-dimensional texture. Therefore, it is possible to generate a three-dimensional texture that expresses unevenness information on the object surface with high accuracy.

  According to the third aspect of the present invention, since the direction of the line of sight with respect to the direction of the virtual light source that outputs the maximum reflectance of the bidirectional reflectance distribution function is calculated as the regular reflection direction, the object is irradiated with light from a predetermined direction. In this case, it is possible to obtain a three-dimensional texture reflecting the physical law that the reflectance of light in the regular reflection direction is the highest among the reflected light, and a more realistic computer simulation can be performed.

  According to the fourth aspect of the invention, since the variation is given so that the normal vector follows a predetermined probability density function, it is possible to prevent the normal vector from being biased in a specific direction.

  According to the fifth aspect of the present invention, the user can select a favorite three-dimensional texture from a plurality of three-dimensional textures.

  According to the sixth aspect of the present invention, it is possible to give rough unevenness (for example, wrinkles) on the object surface as an offset value of each sample point, thereby three-dimensionally expressing the unevenness information of the object more accurately. A texture can be generated.

  According to the seventh and eighth aspects of the invention, the same effect as that of the first aspect of the invention can be obtained.

(Embodiment 1)
Embodiment 1 of the present invention will be described below. FIG. 1 shows a block configuration diagram of a texture generating apparatus according to Embodiment 1 of the present invention. The texture generation device is configured by a known computer, and includes a processing unit 10, a storage unit 20, an input unit 30, a display unit 40, and a BRDF (Bidirectional Reflectance Distribution Function) acquisition device 50. .

  The processing unit 10 includes a CPU, and includes a regular reflection direction calculation unit (acquisition unit and regular reflection direction calculation unit) 11, a normal vector calculation unit (normal vector calculation unit) 12, and a concavo-convex information calculation unit (concave / convex information calculation unit). ) 13, a correction unit 14, a display control unit 15, and a rendering processing unit 16. The storage unit 20 includes a storage device such as a hard disk and a ROM, and includes a BRDF storage unit 21, a texture storage unit 22, and a 3D model storage unit 23. The regular reflection direction calculation unit 11 to the rendering processing unit 16 and the BRDF storage unit 21 to the three-dimensional model storage unit 23 are realized by the CPU executing the texture generation program according to the present invention.

  The regular reflection direction calculation unit 11 arranges sample points in a square lattice pattern in a horizontal plane in the virtual three-dimensional space, and irradiates each sample point from a virtual light source arranged at a predetermined position in the virtual three-dimensional space. The light ray direction is input to the BRDF representing the optical characteristics of the object surface to be simulated stored in the BRDF storage unit 21, and the line-of-sight direction when the BRDF outputs the maximum reflectance is defined as the regular reflection direction. calculate.

Here, BRDF is a function that takes the light ray direction and the line-of-sight direction as inputs and outputs the reflectance. In the present embodiment, the BRDF has an input / output relationship expressed by a mathematical expression and an input / output relationship of an LUT.
(Lookup table) format. The reflectance is represented by the ratio of the amount of reflected light to the amount of light emitted from the virtual light source.

  The normal vector calculation unit 12 calculates, for each sample point, a vector whose direction is a straight line that bisects the angle between the ray direction and the line-of-sight direction as the normal vector of the surface including the sample point of interest. .

  The concavo-convex information calculation unit 13 sets the sample points in the Z direction so that a triangular polygon formed by connecting adjacent sample points with a straight line is orthogonal to the normal vector of any sample point constituting the polygon. To change the orientation of the polygon, and calculate the value of the Z component of the sample point as the unevenness information. Thereby, a three-dimensional texture is generated.

  The correction unit 14 corrects the three-dimensional texture calculated by the unevenness information calculation unit 13 or the shape of the three-dimensional texture stored in the texture storage unit 22 according to an operation command from the user.

  The display control unit 15 uses the three-dimensional texture calculated by the unevenness information calculation unit 13, the three-dimensional texture corrected by the correction unit 14, the three-dimensional texture stored in the texture storage unit 22, and the rendering processing unit 16. The rendered image is displayed on the display unit 40. The rendering processing unit 16 texture maps the three-dimensional texture calculated by the unevenness information calculating unit 13 on the virtual three-dimensional model stored in the three-dimensional model storage unit 23 and renders the virtual three-dimensional model.

  The BRDF storage unit 21 stores the BRDF acquired by the BRDF acquisition device 50. The BRDF storage unit 21 may store a BRDF other than the BRDF acquired by the BRDF acquisition device 50. Here, the BRDF other than the BRDF acquired by the BRDF acquisition device 50 is represented by, for example, a BRDF created by a user inputting numerical values using application software for setting the BRDF, or a mathematical expression. BRDF is included.

  Further, the BRDF acquired by the BRDF acquisition device 50 is a BRDF in the LUT format. The BRDF storage unit 21 stores a plurality of types of BRDFs. The texture storage unit 22 stores the texture created by the unevenness information calculation unit 13. The three-dimensional model storage unit 23 stores a virtual three-dimensional model modeled in advance.

  The input unit 30 includes a known input device such as a keyboard and a mouse. The display unit 40 includes a known display device such as a CRT, a liquid crystal panel, a plasma panel, or the like. The BRDF acquisition device 50 is a known device invented by the present applicant. The BRDF acquisition device 50 photographs a sample while changing the light irradiation direction and the photographing direction with respect to the actual sample. It is a device that generates BRDF from an image. Detailed contents are disclosed in JP-A-2005-115645.

  Next, the operation of the texture generating apparatus shown in FIG. 1 will be described using the flowchart shown in FIG. First, in step S1, when the input unit 30 receives an operation command from the user for designating one BRDF from the BRDF storage unit 21, the regular reflection direction calculation unit 11 stores the BRDF designated by the user in the BRDF storage. Read from the unit 21 to obtain the BRDF.

In step S <b> 2, the regular reflection direction calculation unit 11 arranges a plurality of sample points in a virtual three-dimensional space in a lattice pattern, and determines the regular reflection direction of light when light is emitted from the virtual light source to each sample point.
Calculate using RDF. FIG. 3 is a diagram showing sample points arranged in a grid in a virtual three-dimensional space. As shown in FIG. 3, X, Y, and Z axes that are orthogonal to each other are set in the virtual three-dimensional space. Here, the Z axis indicates the vertical direction, and the XY plane indicates the horizontal plane. The regular reflection direction calculation unit 11 arranges the sample points P in a grid pattern on the XY plane in the virtual three-dimensional space. Here, the sample points P are arranged on the XY plane with an interval of mesoscale (scale of micron order to millimeter order). The value of the spacing flaw is preferably about 10 to 100 μm when the object to be simulated is a texture on the surface of an automobile fabric or plastic.

  Hereinafter, among the sample points P arranged on the XY plane, the sample point P to be processed is referred to as a target sample point CP. The regular reflection direction calculation unit 11 obtains the light direction LD from the virtual light source VL with respect to the target sample point CP, inputs the obtained light direction LD to the BRDF obtained in step S1, changes the line-of-sight direction VD, and changes each line-of-sight direction. The reflectance with respect to VD is obtained, and the line-of-sight direction in which the maximum reflectance among the obtained reflectances is obtained is calculated as the regular reflection direction of light at the sample point CP of interest. In the example of FIG. 3, the arrow with the symbol VD is longer as the reflectance is higher, so the line-of-sight direction VGMAX is calculated as the regular reflection direction RD. The specular reflection direction RD is similarly calculated for other sample points P. In FIG. 3, the normal vector n at the sample point CP of interest is displayed exaggerated over the normal vectors n at the other sample points P.

  FIG. 4 is a diagram for explaining the light beam direction LD and the line-of-sight direction VD. As shown in FIG. 4, when the X ′ axis (parallel to the X axis), Y ′ axis (parallel to the Y axis), and Z ′ axis (parallel to the Z axis) are set with the target sample point CP as the origin, the light beam direction LD Is expressed by an angle α formed between the projection LD ′ of the light beam direction LD onto the XY plane and the X ′ axis, and an angle β formed between the projection LD ′ and the light beam direction LD. The line-of-sight direction VD is represented by an angle γ formed by the projection VD ′ of the line-of-sight direction VD onto the XY plane and the X ′ axis, and an angle δ formed by the projection VD ′ and the line-of-sight direction VD.

  Here, the regular reflection direction calculation unit 11 changes the angle δ within a range of 0 to 90 degrees with a predetermined resolution (for example, 5 degrees), and changes the angle γ within a range of −90 to 90 degrees with a predetermined resolution ( For example, the line-of-sight direction VD is changed.

  In step S3 shown in FIG. 2, the normal vector calculation unit 12 sets a vector that bisects the angle θ formed between the specular reflection direction RD and the ray direction LD of the target sample point CP shown in FIG. Is calculated as a normal vector n for a plane including.

  In step S4 shown in FIG. 2, the unevenness information calculating unit 13 calculates unevenness information of the sample point P as follows. FIG. 5 is a diagram for explaining a process in which the concavo-convex information calculation unit 13 calculates the concavo-convex information. FIG. 5A is a diagram when the sample points P arranged on the XY plane are viewed from the Z direction. ) Shows a perspective view of a virtual three-dimensional space in which sample points P are set.

  First, as shown in FIG. 5A, the concavo-convex information calculation unit 13 specifies the polygon PL1 located at the lower left of the two polygons constituting the lower left lattice K1 as the target polygon. Next, as shown in (b), among the three sample points P constituting the polygon PL1, the sample points P2 and P2 are set so that the direction of the polygon PL1 is orthogonal to the normal vector n1 of the lower left sample point P1. P3 is moved in the Z direction, and the value of the Z component of the sample points P2 and P3 after the movement is calculated as the unevenness information of the sample points P2 and P3.

Next, as shown in (a), the unevenness information calculation unit 13 specifies the polygon PL2 positioned at the lower left of the polygons constituting the grid K2 adjacent to the grid K1 as the target polygon, and the orientation of the polygon PL2 is the polygon Among the three sample points P constituting PL2, the sample points P4 and P5 are moved in the Z direction so as to be orthogonal to the normal vector n2 of the lower left sample point P2, and the sample points P4 and P5 after the movement are moved. The value of the Z component is calculated as the unevenness information of the sample points P4 and P5.

  Next, as shown in (a), the unevenness information calculation unit 13 specifies the polygon PL3 in the lattice K3 adjacent to the upper side of the lattice K1 as the target polygon, and the orientation of the polygon PL3 is the normal line of the sample point P3. The sample point P6 is moved in the Z direction so as to be orthogonal to the vector n3, and the value of the Z component of the sample point P6 after the movement is calculated as the unevenness information of the sample point P6.

  Next, the unevenness information calculation unit 13 identifies the polygon PL4 in the lattice K4 adjacent to the right side of the lattice K2 as the target polygon, and changes the orientation of the polygon PL4 in the same manner as the polygon PL2. As described above, the unevenness information calculation unit 13 sequentially identifies the target polygon from the polygon PL1 of the lower left lattice K1 so as to meander obliquely upward to the right, and changes the direction of the identified target polygon as described above. Then, the Z component value of each sample point after the change is calculated as unevenness information of each sample point, and a three-dimensional texture is generated.

  The unevenness information calculation unit 13 sequentially identifies the target polygon so as to meander from the polygons in the lower right, upper left, and upper right grids other than the lower left to meander to the upper left, lower right, and lower left. May be.

  As described above, according to the texture generation device according to the first embodiment, a three-dimensional texture representing the unevenness information of the object surface is generated based on the bidirectional reflectance distribution function of the object. Therefore, the user can obtain a three-dimensional texture representing the unevenness information on the surface of the object only by giving a bidirectional reflectance distribution function of the object to be simulated without modeling the three-dimensional texture. In addition, since a three-dimensional texture corresponding to the object to be simulated is generated, there is no need to modify the three-dimensional texture so that the object has a desired design, and it can be performed quickly without performing complicated work. A three-dimensional texture can be obtained. By rendering the obtained 3D texture to a virtual 3D model, the interior of the car seat can be reproduced realistically, and the interior design can be evaluated without developing an actual prototype. Development costs can be reduced.

  In addition, since the sample points P are arranged in a meso scale, the generated three-dimensional texture represents a three-dimensional meso structure.

(Embodiment 2)
Next, a texture generating apparatus according to Embodiment 2 will be described. FIG. 6 shows a block diagram of the texture generating apparatus according to the second embodiment. The texture generation device according to the second embodiment is characterized in that the texture generation device according to the first embodiment further includes a texture texture storage unit 24. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The wrinkle texture storage unit 24 stores a wrinkle texture, which is a texture representing the unevenness (texture) on the surface of the object represented on a scale that can be visually recognized by the human eye. The texture texture storage unit 24 stores a plurality of patterns of texture texture created in advance.

When the input unit 30 receives an operation command for selecting a texture texture from the user, the regular reflection direction calculation unit 11a reads the texture texture selected by the user from the texture texture storage unit 24, and in accordance with the read texture texture, The sample points P arranged on the XY plane are moved in the Z direction. That is, the regular reflection direction calculation unit 11 sets an offset value for the Z component of the sample point P. In the present embodiment, the regular reflection direction calculation unit 11a corresponds to an example of an offset setting unit.

  FIG. 7 is a flowchart showing the operation of the texture generation apparatus according to the second embodiment. Since the process of step S21 is the same as step S1 shown in FIG. 2, description is abbreviate | omitted. In step S22, the regular reflection direction calculation unit 11a reads a texture texture from the texture texture storage unit 24 in accordance with a user operation command received by the input unit 30, and performs virtual processing in the same manner as in the first embodiment according to the read texture texture. The sample point P arranged in the three-dimensional space is moved in the Z direction.

  FIG. 8 is a diagram illustrating an operation screen displayed on the display unit 40 when the user selects a texture. As shown in FIG. 8, the operation screen displays a main frame MF shown on the left side and six sub-frames SF shown on the right side. In the subframe SF, a plurality of patterns of textures stored in the texture texture storage unit 24 are displayed.

  Here, when any subframe SF is clicked by the user among the plurality of subframes SF, the input unit 30 selects the texture that is displayed in the clicked subframe SF as the texture selected by the user. Accept as texture. At this time, the display control unit 15 causes the texture texture selected by the user to be displayed in the main frame MF. In the example of FIG. 8, the generated three-dimensional texture is displayed on the main frame MF instead of the selected texture.

  A scroll bar SB for scrolling the three-dimensional texture displayed on the main frame MF is displayed on the left side and the lower side of the left side of the main frame MF. When the scroll bar SB is dragged, the display control unit 15 scrolls the grain texture displayed in the main frame MF according to the drag amount of the scroll bar SB.

  FIG. 9 is a diagram illustrating how the sample points P are moved according to the texture. As shown in FIG. 9, the sample points P arranged on the XY plane are translated along the Z axis to the surface of the texture represented by the texture texture mapped on the XY plane. As a result, each sample point represents a rough shape of the object surface.

  In step S23, the regular reflection direction calculation unit 11 irradiates light from the virtual light source VL to each sample point P translated in the Z direction according to the texture in step S22, and performs the same process as in the first embodiment. Then, the regular reflection direction of each sample point P is calculated.

  Steps S24 and S25 are the same as steps S3 and S4 shown in FIG.

  In step S26, the display control unit 15 causes the display unit 40 to display the three-dimensional texture generated through the process of step S25. In this case, the display control unit 15 displays the generated three-dimensional texture on the main frame MF shown in FIG. In the example of FIG. 8, a three-dimensional texture is generated according to the texture texture displayed in the subframe SF in the first row and the third column. It can be seen that the surface shape of the object is realistically reproduced as shown in the main frame MF in FIG.

Here, when the “3D view” button located on the upper side of the main frame MF is clicked, the rendering processing unit 16 uses the generated 3D texture to store the virtual 3D model stored in the 3D model storage unit. After rendering, the display control unit 15 causes the display unit 40 to display the rendered image.

  FIG. 10 is a diagram showing an operation screen including an image rendered by the rendering processing unit 16. When the input unit 30 receives an operation command to click the “Light” button shown on the left side of FIG. 10, the display control unit 15 determines the position of the virtual light source VL, the intensity of light emitted from the virtual light source VL, and the line-of-sight direction VD. An operation screen (not shown) for changing is displayed on the display unit 40, and the user operates the operation screen to adjust the light intensity and the light ray direction and the line-of-sight direction to the three-dimensional texture, and to display the three-dimensional texture. Can be observed.

  When the input unit 30 receives an operation command for clicking the “Edit” button shown in FIG. 10, the display control unit 15 causes the display unit 40 to display an operation screen (not shown) for correcting the three-dimensional texture. When the input unit 30 receives an operation command for correcting the three-dimensional texture (YES in step S27), the correction unit 14 corrects the shape of the three-dimensional texture according to the operation command from the user (S28).

  FIG. 11 shows a cross-sectional view of the three-dimensional texture displayed on the operation screen for correcting the three-dimensional texture, (a) shows a cross-sectional view before correction, and (b) shows a cross-sectional view after correction. ing. As shown in FIGS. 11A and 11B, the three-dimensional texture is represented by a low-frequency component S that represents rough unevenness and a high-frequency component S ′ that represents fine unevenness. Here, the low frequency component S is mainly caused by the texture texture.

  When the input unit 30 receives an operation command for dragging the point P1 and the point P2 on the low frequency component S shown in FIG. 11A to the point P1 ′ and the point P2 ′ shown in FIG. Depending on the drag amount, the height of the low-frequency component shown in FIG. 11A is changed as shown in FIG. 11B to reduce the height of the wrinkles. At this time, the correction unit 14 changes the high frequency component S ′ so as to follow the change of the low frequency component S. As a result, the user can finely adjust the three-dimensional texture and change the height of the texture to a desired size.

  In step S27 shown in FIG. 7, when the input unit 30 does not accept an operation command from the user (NO in S27), the process is terminated.

  FIGS. 12 to 15 are drawings showing rendering results when the virtual three-dimensional model of the interior of the automobile is rendered by bump mapping the three-dimensional texture generated by the texture generating apparatus onto the dashboard of the automobile. . As shown in FIGS. 12 to 15, it is understood that the texture of the dashboard surface is realistically reproduced by rendering using the three-dimensional model generated by the texture generation apparatus.

  As described above, according to the texture generating device according to the second embodiment, in addition to being able to achieve the same operational effects as those of the first embodiment, the texture component is used for the Z component for each sample point P. Since the offset is set, it is possible to obtain a three-dimensional texture that more realistically reproduces the texture shape.

  The present invention may adopt the following aspects.

(1) In steps S3 and S24 of the flowcharts shown in FIGS. 2 and 7, the normal vector n is corrected so that the calculated normal vector n of each sample point P follows a normal distribution, or 1 / f fluctuation is followed. The three-dimensional texture may be generated by performing the processes in steps S4 and S25 using the corrected normal vector n. Furthermore, the three-dimensional texture calculated without correcting the normal vector n, the three-dimensional texture calculated using the normal vector n modified to follow the normal distribution, and the one-f fluctuation are corrected. The three-dimensional textures calculated using the normal vector n are calculated in parallel, displayed in a list in the subframe SF shown in FIG. 8, and are made to be selected by the user when rendering. It may be.

  (2) In Embodiment 2, the emboss is exemplified as the offset value to be given to each sample point P. However, the present invention is not limited to this, and a solid shape other than the emboss may be given as the offset value. The set offset value may be arbitrarily adjusted by the user operating the input unit 30.

1 shows a block configuration diagram of a texture generation device according to Embodiment 1 of the present invention. FIG. It is a flowchart which shows operation | movement of the texture production | generation apparatus shown in FIG. It is the figure which showed the sample point arranged in the grid | lattice form in the virtual three-dimensional space. It is drawing explaining the light ray direction LD and the line-of-sight direction VD. It is drawing explaining the uneven | corrugated information calculation, (a) shows drawing when the sample point arranged on XY plane is seen from a Z direction, (b) is virtual 3 where the sample point was set. FIG. 2 shows a perspective view of a dimensional space. The block block diagram of the texture production | generation apparatus by Embodiment 2 of this invention is shown. It is a flowchart which shows operation | movement of the texture production | generation apparatus shown in FIG. It is drawing which shows the operation screen which selects a texture texture. It is drawing which shows a mode that the sample point P is moved according to a texture texture. It is drawing which shows the operation screen on which the three-dimensional texture was displayed. A cross-sectional view of a three-dimensional texture is shown. It is drawing which shows the result of a rendering process. It is drawing which shows the result of a rendering process. It is drawing which shows the result of a rendering process. It is drawing which shows the result of a rendering process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Processing part 11 Regular reflection direction calculation part 12 Normal vector calculation part 13 Concave / convex information calculation part 14 Correction part 15 Display control part 16 Rendering process part 20 Storage part 21 BRDF storage part 22 Texture storage part 23 3D model storage part 24 Texture storage unit 30 Input unit 40 Display unit 50 BRDF acquisition device

Claims (8)

A texture generation program for generating a three-dimensional texture representing unevenness information on an object surface,
Obtaining means for obtaining a bidirectional reflectance distribution function of the object;
A texture generation program that causes a computer to function as a generation unit that generates a three-dimensional texture based on the bidirectional reflectance distribution function acquired by the acquisition unit. The generating means includes
A regular reflection direction in which a plurality of sample points are arranged in a virtual three-dimensional space, and a regular reflection direction of light emitted from the virtual light source to each of the arranged sample points is calculated using the bidirectional reflectance distribution function A calculation means;
Normal vector calculation means for calculating a normal vector of each sample point from the regular reflection direction of light calculated by the regular reflection direction calculation means and the incident direction of light from the virtual light source;
The texture generating program according to claim 1, further comprising unevenness information calculating means for calculating unevenness information of each sample point based on the normal vector calculated by the normal vector calculating means.   The texture generation according to claim 2, wherein the regular reflection direction calculation unit calculates the direction of the line of sight with respect to the direction of the virtual light source that outputs the maximum reflectance of the bidirectional reflectance distribution function as the regular reflection direction. program. The normal vector calculation means corrects by giving variation so that the direction of the normal vector of each sample point follows a predetermined probability density function,
The texture generation program according to claim 2 or 3, wherein the unevenness information calculating means calculates unevenness information of each sample point using a normal vector corrected by the probability density function. The concavo-convex information calculating means is calculated using a three-dimensional texture composed of concavo-convex information calculated using a normal vector not corrected by the probability density function and a normal vector corrected by the probability density function. Calculated 3D texture composed of the uneven information,
The computer is caused to further function as a presentation unit that presents a plurality of three-dimensional textures calculated by the unevenness information calculation unit to the user and receives a command from the user that selects any one of the presented three-dimensional textures. The texture generation program according to claim 4, wherein:   6. The texture generation program according to claim 2, wherein the computer further functions as an offset setting means for setting an offset value in the height direction for each sample point. A texture generation device for generating a three-dimensional texture representing the structure of an object surface,
Obtaining means for obtaining a bidirectional reflectance distribution function of the object;
A texture generating apparatus comprising: generating means for generating a three-dimensional texture based on the bidirectional reflectance distribution function acquired by the acquiring means. A texture generation method in which a computer generates a three-dimensional texture representing a structure of an object surface,
Obtaining a bidirectional reflectance distribution function of the object;
A texture generation method comprising: a generation step of generating a three-dimensional texture based on the bidirectional reflectance distribution function acquired in the acquisition step.