JPH0935087A - Method and device for shade processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the number of polygons required for shade generation by approximating a complicated three-dimensional shape body which generates a shade with several solid bodies and replacing them with planes which generating nearly the same shade. SOLUTION: A 1st solid model 151 represents a three-dimensional shape body as a set of polygons and polyhedrons. A 2nd solid model 152 approximates and represents the 1st solid model 151 as a set of, for example, elliptic bodies and rectangular prisms by using an approximate model generating means 161. As data on the three-dimensional shape body, the 1st solid model 151 and further the 2nd solid model 152 which is represented by approximation with less parameters than it are provided. Then a shade generation rule calculating means 155 finds a rule for generating the shade of the 2nd solid model from data 153 regarding a light source and a shade adding means 160 finds the shade formed by a shield surface. Consequently, even if the solid model 151 is in a complicated shape, the shield surface can easily be found from the data 153.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applicable to movies, games, arts,
The present invention relates to industries such as science, and more particularly to a method or apparatus for creating and displaying images and videos by a computer.

[0002]

2. Description of the Related Art Computer graphics (hereinafter referred to as C
The term "G" refers to a technique for creating an image or a video using a computer or the like, or a work thereof, and recently, it has been widely involved in the field of multimedia in general. Examples of technologies related to CG include modeling technology for converting a shape into a data format handled by a computer, three-dimensional processing technology such as perspective projection, and rendering technology for realistically coloring a surface.

In general, the CG creation method currently used is to convert a three-dimensional object into a polygon such as a triangle or a quadrangle (hereinafter, referred to as a polygon).
Model as a set of polygons (mesh division),
In many cases, the process of obtaining the overlap of the objects from the viewpoint and performing the surface treatment according to the properties of the light source and the object is taken. On the other hand, in CG, there is a demand to express a real thing as realistically as possible. As one of the effects for making a three-dimensional object look realistic, it is conceivable to add a shadow, and its techniques include ray tracing, two-step method, shadow volume and the like.

Ray tracing is a method in which the line of sight is reversely searched from the object side, and if an object exists before the light source is reached, that part is shaded. The two-step method is a method of obtaining a perspective view from a viewpoint and a perspective view from a light source, and superimposing a portion that does not appear in the perspective view from the light source as a shadow on the perspective view from the viewpoint. The shadow volume is a method in which an area of a shadow generated by a light source and an occluding surface is obtained as a shadow solid (shadow volume), and an intersecting portion of an object overlapping this solid is set as a shadow.

Further, as a document relating to a method of adding a shadow by a computer, "Shadow Algorithm for Computer Graphics" 197 is cited.
7'Siegraph (Shadow Algorithms
for Computer Graphics "19
77 'SIGGRAPH) is well known. Japanese Patent Application Laid-Open No. 4-65780 is an already-applied patent that enables high-speed processing by performing shading processing by hardware. Further, there is Japanese Patent Application Laid-Open No. 2-24785 as an already-applied patent in which an object illuminated by a light source is discriminated and drawing processing is performed based on the discrimination result to shorten the shadow addition time.

[0006]

However, when the shadow formed by one object on another object in CG is to be obtained, there is a problem that the drawing processing speed of CG is extremely reduced due to the problem of the amount of calculation. If the object on the screen does not move and the position of the light source does not change, the shape of the shadow does not change. Therefore, the shadow may be obtained once when the CG data is created. However, when the object moves or the direction of the light source changes dynamically, it is necessary to obtain the shadow each time.

For an image in which an object or light source in the image moves,
Shading such data in real time (about 10 frames per second) is practically impossible in consideration of the processing capability of the current hardware. When the displayed three-dimensional object moves in an arbitrary direction or the position or direction of the light source changes, it is necessary to calculate the shadow shape each time. Generally, when it is attempted to model a real object or landscape to some extent realistically, each of the objects (objects) that form a shadow is about several thousand polygons, and the whole image often exceeds tens of thousands of polygons.

Since the calculation for obtaining the shadow increases substantially in proportion to the number of objects and the complexity of the shape, the CG drawing is delayed and the motion of the displayed image is extremely slow because of the calculation time. There is a problem that the object becomes awkward and the motion of the object looks awkward. A method to improve the processing speed by devising the hardware and software (such as the above-mentioned publicly known example) has been considered, but it has not yet been possible to perform real-time processing of a complicated model, and it is even faster. Processing is required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for adding a shadow to an image containing an object having a complicated shape at high speed in order to solve the above problems. Another object of the present invention is to
In order to solve the above-mentioned problem, it is an object of the present invention to provide a device for quickly adding a shadow to an image including an object having a complicated shape.
Another object of the present invention is to add shadows at high speed with a simple structure that does not require special hardware.
Or to provide a device.

[0010]

In order to solve the above-mentioned problems, according to the present invention, the three-dimensional shaped object is represented by m from the first three-dimensional model expressing the three-dimensional shaped object by m parameters.
The second model under the light generated by the light source, based on the approximate model creating means for creating a second three-dimensional model represented by n parameters with n> n, the data about the light source, and the second three-dimensional model. And a means for adding the shadow generated according to the shadow generation rule to the object on which the shadow appears as the shadow generated by the first stereo model.

Further, according to the present invention, from the first three-dimensional model expressing the three-dimensional shaped object with m parameters, the second three-dimensional model expressing the three-dimensional shaped object with n parameters satisfying m> n. Is generated, the shielding surface of the second three-dimensional model under the light generated by the light source is obtained from the data about the light source and the second three-dimensional model, and the shielding surface is approximated to a polygon. The shadow generated by the polygon is added to the object on which the shadow is reflected as the shadow generated by the first stereo model.

[0012]

As data for representing a three-dimensional object, in addition to the three-dimensional shape data represented by the first three-dimensional model, there is a second three-dimensional model which is approximately represented by a smaller number of parameters for shadow generation. At the time of shadow generation, a shadow generation rule such as a plane that generates the same shadow as the shadow generated by the solid, that is, a shielding surface by the solid is calculated from the data about the light source such as the direction of the light source and the second solid model. Ask. By adding the resulting shadow to the first three-dimensional model, it is possible to add the shadow by a significantly smaller number of operations than directly obtaining the shadow by the first three-dimensional model.

For example, consider the case where a set of ellipsoids is used for the second stereo model. Since an ellipsoid is an ellipse when viewed from any direction, if an object with a complicated shape is approximated to a set of ellipses, the obstruction surface will be the elliptical plane regardless of the direction of light. Can be easily obtained as a set of. In addition, by approximating this elliptical plane as several polygons and replacing it with the original solid, the amount of calculation when obtaining the shadow by the conventional method can be greatly reduced and the drawing speed can be increased. it can. As an already-applied patent for approximating a three-dimensional object to an ellipsoid, there is Japanese Patent Application No. 6-17112.

If the second stereo model approximating the first stereo model is a set of solids that can be represented with fewer parameters than the first stereo model even if it is not an ellipsoid, then the The shielding surface can be easily obtained. By using this instead of the first stereo model for generating the shadow, the object for generating the shadow has a simple shape, and the amount of calculation for calculating the shadow can be significantly reduced. The shape of the shadow is somewhat inaccurate because it is an approximation, but in general applications, it is not necessary to obtain the shape of the shadow very precisely. Even if an approximate model is used, the reality of the entire image can be maintained sufficiently.

[0015]

First, the overall concept of the present invention will be described with reference to FIG. The first three-dimensional model 151 is specifically a general C
Similarly to G, the three-dimensional object is expressed as a set of polygons or polyhedra. For example, if this is expressed as a set of quadrilateral polygons, if the number of polygons is 20,000
, The four vertex coordinates of each polygon are x, y, z
The total number of parameters m is 4 ×
3 × 20000 = 240000.

The second three-dimensional model 152 is a representation of the first three-dimensional model 151 approximated as a set of, for example, an ellipsoid or a rectangular parallelepiped using the approximate model generation means 161. If this first three-dimensional model 151 is approximated by a set of 300 ellipsoids, one ellipsoid can be represented by 9 parameters, so the total number of parameters n is 9 × 300 = 2700. Be done.

As described above, in the present invention, as the data of the three-dimensional shaped object (hereinafter referred to as an object), in addition to the first three-dimensional model 151, the second three-dimensional model 152 represented by less parameters by approximation is provided. . A specific example of the approximate model generation means 161 will be described later.

The above is the modeling process in CG. In the subsequent rendering process, first, from the data 153 on the light source such as the direction of the light ray, the shadow generation rule calculation means 155 obtains the rule for generating the shadow of the second stereo model by the light source. Specifically, for example, from a parameter expressing the shape of the second stereo model 152 and data such as a light ray direction regarding a light source, a shading surface that generates the same shadow as the shadow generated by the second stereo model 152 is selected. calculate. After that, the shadow adding means 1
By 60, the shadow due to this shielding surface is obtained. Three-dimensional processing is performed according to the viewpoint position and the type of projection method, and rendering is performed and displayed.

By these means, the first three-dimensional model 1
Even when 51 has a complicated shape, when the shadow is generated, the second solid model 152 and the light source data 15 are generated.
The shielding surface can be easily obtained from 3. Since this occluding surface is a simpler figure than the first three-dimensional model 151, the process of obtaining the shadow by this occluding surface can be made extremely less than that by the model and the model.

An embodiment of the present invention will be specifically described below. 6 and 7 show examples of devices to which the present invention is applied.
FIG. 3 is a schematic configuration diagram of an editing device for creating data of objects and backgrounds. This editing device mainly performs a modeling process in CG. Figure 7
FIG. 4 is a schematic configuration diagram of an execution device that displays data created by the editing device as a video. It is possible to interactively change the position and direction of the object, the position and direction of the viewpoint, or the position and direction of the light source by inputting by the user. This execution device mainly performs a rendering process in CG and a three-dimensional processing process.

A video game can be considered as one of the application examples. The editing device is mainly operated by the game creator, and the execution device is mainly operated by the game player. First, FIG. 6 will be described. The editing device 900 includes an input / output control unit 904 that controls a graphical user interface such as a mouse 901, a keyboard 902, and a display 903, a processor (hereinafter, referred to as CPU) 905 that executes a program, an external hard disk 910, a floppy disk 911, and the like. It comprises a storage device, a main memory 912 for storing programs and data, and the like.

The operation of various programs will be described below.
These programs are actually executed by the CPU 905. In explaining the operation, as an example, consider that an object 201 as shown in FIG. 2 is displayed with a shadow added thereto. Each program and data stored in the main memory 912 will be described.

The shape creation program 906 performs three-dimensional modeling of an object. An object 201 as shown in FIG. 2 is expressed as a set of triangular or quadrangular polygons as shown by the modeled object 301 in FIG. 3 (called mesh division). Here, as an example, modeling using a quadrilateral polygon is taken up. The modeled object 301 corresponds to the first stereo model 151 in FIG. Shape creation program 90
Many of 6 are currently being developed, but a typical one is to interactively create a model by operating a mouse or the like while looking at the display screen. The present embodiment also assumes the use of such an existing program. The shape creation program 906 outputs the data of the modeled object 301 as object shape data 908.

The object shape data 908 may have various formats, but in the present embodiment, FIG.
It has a format as shown in (b). As shown in FIG. 8A, each object is divided into finer objects having a plurality of hierarchies constituting the object (908-
1), the lowest layer object describes the IDs of the polygons that compose it. Then, as shown in FIG.
Describe the coordinate value of each vertex of the polygon (908-
2).

The objects are hierarchized in this manner by, for example, disassembling an object such as a person into objects such as a hand and a body, and then forming a shape in which only the hand is moved or the whole body while walking. This is because it is possible to easily create a model that moves. Coordinates can be described in the absolute coordinate system, but in consideration of the movement of the object, the coordinates will be described in the relative coordinate system. In the actual CG, other data such as attribute data (color, material, etc.) of the object is also described, but the description is omitted because it does not particularly affect the present invention.

Next, the approximate model creation program 907 will be described. The approximate model creation program 907 is
In order to define the modeled object 301 created by the shape creation program 906 as a shield (creating a shadow), it is approximated as a set of solids such as an ellipsoid and a rectangular parallelepiped. In this embodiment, the approximation is performed as a set of ellipsoids. As shown in FIG. 4, an approximate model 401 approximated by a set of only a few to a few tens of ellipsoids is created so that the outline of the object 201 is almost the same. This corresponds to the second stereo model in FIG. 1, and the approximate model creating program 907 corresponds to the approximate model generating means 161.
At this time, you can ignore the overlap of each ellipsoid,
If each part of the object 201 is connected,
Avoid being separated by the ellipsoidal approximation.

The approximate model creation program 907 in this embodiment controls a graphical user interface and the like, and the approximate model 4 is interactively operated by a user operation.
01 is supported. For example, by displaying the object model 201 viewed from an arbitrary direction and the approximate model 401 in an overlapping manner, and allowing the operator (the game creator in the above example) to correct the approximate model in the direction in which the difference becomes large, Create an approximate model.

FIG. 12 shows an example of the editing screen 550 displayed on the display 903, which is displayed on the entire screen or in one window. The approximate model creation program 907 allows the user to input a direction instruction interface 55.
A two-dimensional image in which the modeled object 301 and the ellipsoid 562 viewed from an arbitrary position specified in 3 overlap each other is displayed in the editing window 560.

Then, the ellipsoid 5 is displayed in the edit window 560.
The ellipse shape definition control point 563 of 62 is displayed, and the user drags this with the mouse 901 to adjust the size and position of the ellipsoid. Such an operation is performed from various viewpoints, and the approximation model 401 is completed and defined when the difference between the modeled object 301 and the approximation model 401 is minimized in any direction. At the same time, when the approximate model 401 is three-dimensionally displayed on the reference window 570 by perspective projection, the approximate model 401 can be referred to during modeling.

The above-described process proceeds in a completely interactive manner as in the present embodiment, and, for example, a condition that the sum of squares of the deviation between the approximate model 401 and the modeled object 301 is minimized. It is also possible to automatically ask for it by setting such as.

The ellipsoid is represented by a total of 9 variables including 3 variables as the center coordinates of the ellipsoid, 3 variables as the axial length of the ellipsoid, and 3 variables as the axial direction of the ellipsoid. The approximate model creation program 907 obtains these nine variables by the number of ellipsoids forming the approximate model 401 and stores them as approximate model data 909. Approximate model data 90
Reference numeral 9 describes the correspondence 981 between the nine variables 982 of the ellipsoid shown in FIG. 9B and the ellipsoid shown in FIG. 9A and the original object shape model.

As described above, the shape creation program 906
Then, the object shape data 908 and the approximate model data 909 output by the approximate model creation program 907 form a pair, and become the CG model data in this embodiment. The created data is stored in the external storage device such as the hard disk 910 or the floppy disk 911.

Next, FIG. 7 will be described. Execution device 95
0 is an input device 951 such as a mouse or a joystick
And a display 9 including an input / output control unit 955 for controlling it, a rendering unit, a three-dimensional processing unit, and a shadow processing unit.
A graphic board 954 for controlling 53, a processor (hereinafter, referred to as CPU) 95 for executing a program
6, hard disk 962 and floppy disk 963
And an external storage device such as a main memory 964 for storing programs and data. Also, as in the case of the editing device 900, the various programs whose operations are described are actually executed by the CPU 956.

First, as a preprocessing, the user moves the model data from the editing device to the execution device. As a moving means, a replaceable storage medium such as a floppy disk or an optical disk may be used, and it may also be transferred via a network or the like. The object shape data 908 and the approximate model data 909 are read into the main memory of the execution device.

Next, the object operation control program 957 and the light source operation control 9 stored in the main memory 964.
The 58 program will be described. These programs are generally called scenarios, and give various movements to an object or a light source according to a user's input or the passage of time. Generally, this program is often created in advance by a dedicated editor called a scenario editor.

When the CPU 956 executes the object motion control program 957, the user (the game player in the above example) uses the input device 951 at the time of execution (when the game is executed) to determine the position and direction of the object on the screen. Can be changed freely. Also, the object can be set to automatically move according to a certain rule. Specifically, the user's input event and a timer are monitored, and when the event is received, the position of the object is changed. Changing the position of the object means giving a movement calculation or a rotation calculation to the coordinate values of the object shape data 908 and the approximate model data 909.

The light source operation control program 958 has light source data inside, and when the CPU 956 executes this program, the timer (not shown) of the execution unit 950 is monitored and the position of the light source is automatically detected. Control so that it changes.

Next, the rendering process of drawing this object on the screen will be described. CPU965 is
The occluding surface calculation program 959 is executed to perform preprocessing for simplifying the calculation of the shadow in the general rendering process. Specifically, first, for all the ellipsoids of the approximate model data 909 created by the editing device 900,
Using the light source direction data (hereinafter referred to as light source parameter) passed from the light source operation control program 958, a shading surface that produces the same shadow as the shadow produced by the ellipsoid is obtained. Since the ellipsoid is an ellipse from any direction, this blocking surface is an elliptical plane. This process will be described with reference to FIG.

FIG. 10 (a) shows an ellipsoid and its shadow, and FIG. 10 (b) shows the ellipsoidal plane which is the shielding surface of the ellipsoid of FIG. 10 (a) and its shadow. There is. The ellipsoid whose center is at the origin of the coordinates (Equation 1)

[0040]

[Equation 1]

When illuminating with parallel light from the above (p, q, r) toward the origin of the coordinates, first, (Equation 2) is obtained.

[0042]

[Equation 2]

Using this result, the shielding surface of this ellipsoid becomes an elliptical plane as in (Equation 3). Note that θ is the inclination of the ellipsoidal plane when the y direction of the coordinates of the ellipsoid is the upward direction.

[0044]

(Equation 3)

This elliptical plane is polygon-approximated as shown in FIG. 10C to obtain polygon-approximate shielding surface data 960.

As shown in this figure, it can be seen that the shadow of this polygon and the shadow of the original ellipsoid roughly match. In the polygon approximation, the polygon is divided into triangular and quadrangular polygons as shown in FIG. In this embodiment, the polygon is divided into several polygons, but the number of polygons to be divided is adjusted depending on the relationship between accuracy and processing speed. As a means of polygon approximation, for example, the deviation between the generated polygon and the ellipse is automatically calculated so as to be the minimum.

After performing this process for all ellipsoids, the shielding surface calculation program 959 is the object shape data 908 and the polygon approximate shielding surface data 960.
To the graphic board. Graphic board 95
Reference numeral 4 is for adding each of the objects described in the object shape data 908 with a shadow created from the approximate polygonal shading surface data 960 obtained in the above process, coloring the surface realistically, and performing 3 such as perspective projection. Dimensional processing is performed and the result is displayed on the screen of the display 953. This process is performed by hardware by a conventionally known method (two-step method, shadow volume, etc.) which is generally used at present.

Since the approximate model data 909 is used only for obtaining an object that forms a shadow, it is not necessary to pass the processing for creating a shadow to the graphic board. FIG. 13 is a flowchart summarizing the above processing in the execution device 950. First, the object shape data 908 and the approximate model data 909 created by the editing device 900 are read (1010).

Object motion control program 957
Changes the coordinate value of the moving object shape data 908 based on a predetermined motion or a motion according to an event (1030) from the user (1020, 1035). This is equivalent to, for example, that the airplane, which is an example of the object 201, performs a predetermined flight motion, and that the user controls the airplane. After that, the object shape data 9
The coordinate value of each ellipsoid of the approximate model data 909 corresponding to 08 is changed (1040). If there is no change in the coordinates of the object shape data 908, this step may be omitted.

The light source operation control program 958 changes the light source parameter and changes the position and direction of the light source according to the event (1050) from the user or the event (1060) from the timer (1055, 1).
065). This corresponds to, for example, the light source being controlled by the operation of the user, and the position of the sun changing with the passage of time.

The shielding surface calculation program 959 finds the shielding surface from the position and direction of the light source for all ellipsoids in the approximate model data 909 (107).
0), this shielding surface is polygon-approximated as an object that creates a shadow, and polygon approximate shielding surface data 960 is generated (1080). If there is no change in the coordinates of the object and no change in the position or direction of the light source, these steps may be omitted.

The CPU 956 transfers the object shape data 908, the approximate polygonal occluding surface data 960, and the light source parameter to the graphic board 954. The graphic board 954 renders and shades the target object and displays a three-dimensional image such as perspective projection (1090). Hereinafter, these processes are repeated.

In the shading process, when a certain object is focused on, when the object is composed of elements of, for example, several thousand polygons, the conventional method needs to process only this number of polygons, which is very time consuming. Was there. However, according to the present embodiment, since an object having a three-dimensionally complicated shape is approximated to several elliptic solids and this is replaced with an elliptic plane, the number of polygons to be processed is reduced to several tenths. Can be reduced. Two new processes are required: replacement with an ellipse solid cross section (elliptical plane) and ellipse polygon approximation. However, since the shape of a cross section with an ellipse solid can be easily obtained, this process is performed with shadowing. Few compared to the process. As a whole, the shadow processing time at the time of rendering can be significantly reduced.

The error due to approximation is (1) the shape of the shadow is
Except for special cases, it does not affect appearance even if it is not calculated very precisely. (2) The shape of a general object is easy to approximate to a set of elliptic solids. (3) The shielding object to be used finally is a plane ( Although it is an ellipsoidal plane, it can be made extremely inconspicuous due to the fact that it produces the same shading effect as when a solid (ellipsoid) is used.

As a result, it is impossible to display the shadow without delay when the displayed object moves or the light source changes due to the limitation of the hardware performance. This model can also be displayed in real time, that is, about several tens of seconds per second.

Further, in the present embodiment, the approximation is performed only with the ellipsoid, but it may be more appropriate to perform the approximation with another solid such as a polyhedron or a curved surface. In the case of a polyhedron, the shielding surface can be obtained from the coordinates of the vertices and the direction of the light source. In the case of a curved body, the shielding surface can be obtained from the equation and the direction of the light source.
In these cases, the shielding surface cannot be simply obtained as in the above-described ellipsoidal embodiment, but can be obtained by a smaller number of operations than directly obtained from the original polygon model.

In addition, these plural kinds of solids (ellipsoids,
Approximations based on polyhedrons and curved bodies may be arbitrarily mixed. Also, prepare multiple shielding surfaces in advance,
It is also possible to select a shading surface that best fits the ray when the ray hits it from a certain direction and obtain this shadow.
Although this method provides a rough approximation, the processing for obtaining the occluding surface can be omitted, so that the shadow addition processing time can be further shortened. At the time of rendering, select the data in the column closest to the direction of the ray and use it as the blocking surface.

Further, when the structure of the object for forming the shadow is composed of a plurality of ellipsoids as in the present embodiment, when the shadows are obtained for all the respective shielding surfaces, the overlapping parts as seen from the direction of the light source are detected. The calculation is repeated, which is redundant in terms of processing. Therefore, in the shading surface calculation program 959, the shape of the outermost contour of the shading surface forming the object when seen from the light source side is obtained and redefined as the shading surface.
You can also reduce the amount of calculation. Specifically, all the shielding surfaces (ellipsoidal planes approximated by polygons) are projected onto a certain plane, the inside is filled, and the operation of taking the logical sum of the respective shielding surfaces is performed. Then, find that contour line,
The polygon approximate shielding surface data 960 may be used.

Further, in this embodiment, even when the conventional object shape data having no corresponding approximate model data is input to the execution device 950, the object shape data is shielded from the object shape data without being replaced with the approximate model data. The shadow can be added by obtaining the surface. That is, the shadow can be displayed even for data created by another system, or for data for which it is not necessary to create an approximate model because the shape is simple.

In such a case, by adding header information indicating whether or not the object shape data has corresponding approximate model data to the object shape data, the execution device 950 can automatically distinguish and process. You can In this embodiment, the editing device 900 and the execution device 950 are different devices, but they can be built in the same device. In the present embodiment, it is assumed that the software performs the processing for obtaining the occluding surface and the graphic board performs the calculation and drawing of the shadow, but the process for obtaining the occluding surface is a formalized process, so it has a function on the board. In addition, the processing time can be shortened. On the contrary, if a high-speed CPU can be used, all the processes can be made into software.

[0061]

According to the present invention, a complex three-dimensional object that forms a shadow is approximated by several solids, and this is replaced with a plane that generates almost the same shadow, which is necessary for shadow generation. The number of polygons can be significantly reduced. In other words, by simplifying the object that creates the shadow, it is possible to significantly reduce the shadow processing time during rendering. Therefore, there is an excellent effect that real-time display is possible while performing realistic display such as shading.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the overall flow of the present invention.

FIG. 2 is a diagram illustrating a three-dimensional shaped object (object) to be displayed.

FIG. 3 is a diagram illustrating an example of mesh division of the three-dimensional shaped object shown in FIG.

FIG. 4 is a diagram illustrating an ellipsoidal approximation model of the mesh-divided three-dimensional shaped object shown in FIG. 3;

FIG. 5 is a diagram illustrating an example of a shaded image to be finally displayed.

FIG. 6 is a block diagram showing a configuration of an editing apparatus according to an embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of an execution device according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating a data structure of an object model.

FIG. 9 is a diagram illustrating a data structure of an ellipsoidal approximation model.

FIG. 10 is a diagram illustrating an ellipsoid, an ellipse plane, and a shadow of a polygon that approximates the ellipse plane.

FIG. 11 is a diagram exemplifying polygon approximation of an elliptical plane.

FIG. 12 is a diagram illustrating an operation screen of an ellipsoidal approximation model creation editor.

FIG. 13 is a diagram showing an operation flowchart of the execution device according to the embodiment of the present invention.

[Explanation of symbols]

201 ... Object, 301 ... Modeling object, 401 ... Approximation model, 906 ... Shape creation program, 907 ... Approximation model creation program, 908 ... Object shape data, 909 ... Approximation model data, 95
7 ... Object operation control program, 958 ... Light source operation control program, 959 ... Shielding surface calculation program,
960 ... Approximate polygon shielding surface data.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiyuki Yuasa 1099, Ozenji, Aso-ku, Kawasaki-shi, Kanagawa Stock Company Hitachi Systems Development Laboratory

Claims (8)

[Claims] 1. From the first three-dimensional model expressing a three-dimensional shaped object with m parameters, the three-dimensional shaped object is m>
The second model under the light generated by the light source is calculated from the approximation model creating means for creating a second three-dimensional model represented by n parameters, and the data about the light source and the second three-dimensional model. A shadow processing apparatus comprising: means for obtaining a shadow generation rule of a stereo model; and means for adding a shadow generated according to the shadow generation rule to an object on which the shadow appears as a shadow generated by the first stereo model. 2. A three-dimensional shaped object is expressed by m parameters from a first three-dimensional model that represents the three-dimensional shaped object by m>.
An approximate model creating apparatus comprising approximate model creating means for creating a second three-dimensional model represented by n parameters of n. 3. A second three-dimensional model representing a three-dimensional shaped object with n parameters and data concerning a light source,
A means for obtaining a shadow generation rule of the second three-dimensional model under the light generated by the light source; and a shadow generated according to the shadow generation rule with m parameters of m> n for the three-dimensional object. A shadow processing apparatus comprising means for adding a shadow generated by the first three-dimensional model to be expressed to an object on which the shadow is reflected. 4. A second three-dimensional model which represents a three-dimensional shaped object represented by a first three-dimensional model consisting of m parameters by a set of three-dimensional shaped objects consisting of n parameters satisfying m> n. And a means for obtaining a shadow generation rule of the second three-dimensional model under the light generated by the light source from the light source data and the second three-dimensional model. 5. From the first three-dimensional model expressing a three-dimensional shaped object with m parameters, the three-dimensional shaped object is m>
A second three-dimensional model represented by n parameters of n is created, and the shielding of the second three-dimensional model under the light generated by the light source from the data about the light source and the second three-dimensional model. A shadow processing method for obtaining a surface, approximating the obstructing surface to a polygon, and adding the shadow generated by the polygon to the object on which the shadow is reflected as the shadow generated by the first stereo model. 6. The shading processing method according to claim 5, wherein the second three-dimensional model is composed of a set of ellipsoids, and the shielding surface is an ellipsoidal plane. 7. The shadow processing method according to claim 5, wherein the second three-dimensional model is composed of a set of curved bodies, and the shielding surface is a curved surface. 8. A three-dimensional shaped object is expressed by m parameters, and the three-dimensional shaped object is m>
A second solid model expressed as a set of polyhedra expressed by n parameters of n is created, and the light source is generated from the data on the light source and the direction and shape of each of the polyhedra forming the second solid model. The polygons that form the occluding surface of each of the polyhedra under the light are obtained, and the shadows generated by the polygons are added to the object on which the shadows are reflected as the shadows generated by the first stereo model. Shading processing method.