JP6199101B2 - Drawing method, drawing apparatus, and drawing program - Google Patents

Description

  The present invention relates to a drawing method, a drawing apparatus, and a drawing program.

  Conventionally, a three-dimensional image is drawn on a display, a three-dimensional image drawn on a display is enlarged or reduced, or a three-dimensional image drawn on a display is changed with a line-of-sight direction. Things have been done. In addition, there is a technique in which drawing of a three-dimensional image is partially omitted in order to suppress a load on drawing processing.

  As related technologies, for example, the object is drawn as an original three-dimensional shape, drawn into a planar shape, drawn into a line segment shape, or drawn (or drawn as a point). There is something that decides what to do. Specifically, the computer calculates the maximum number of dots in the x, y, and z directions when each object is drawn on the screen, and the predetermined reference values Lx, Ly corresponding to the respective objects are calculated. , Lz, and how to draw is determined.

JP 2002-216164 A

  However, in the above-described prior art, when drawing a three-dimensional image on a display in order to reduce the load on the drawing process in order to partially draw the three-dimensional image, the portion characterizing the shape of the three-dimensional image Drawing may be omitted and the shape of the three-dimensional image may be greatly collapsed. For example, even if an object has a small size in a three-dimensional image, if the object forms a portion characterizing the shape of the three-dimensional image, if the drawing of the object is omitted, the shape of the three-dimensional image is greatly collapsed.

  In one aspect, an object of the present invention is to provide a drawing method, a drawing apparatus, and a drawing program capable of maintaining the shape of a three-dimensional image while partially omitting drawing of the three-dimensional image. .

  According to one aspect of the present invention, the thinning process is performed on the mesh according to a thinning level that is set for a mesh forming a three-dimensional image and indicates a degree of deletion of a plurality of vertex data representing the mesh. A drawing method, a drawing device, and a drawing program for performing drawing processing of the three-dimensional image based on the processed vertex data of the mesh are proposed.

  According to one aspect of the present invention, there is an effect that the shape of a three-dimensional image can be maintained while partially omitting drawing of the three-dimensional image.

FIG. 1 is an explanatory diagram illustrating a specific example of the drawing process of the drawing apparatus 100. FIG. 2 is a block diagram illustrating a hardware configuration example of the drawing apparatus 100 according to the embodiment. FIG. 3 is an explanatory diagram showing an example of the data structure of the drawing data 300. FIG. 4 is a block diagram illustrating a functional configuration example of the drawing apparatus 100. FIG. 5 is an explanatory diagram showing the contents of the drawing process of the drawing apparatus 100. FIG. 6 is a flowchart illustrating an example of a drawing processing procedure of the drawing apparatus 100. FIG. 7 is a flowchart illustrating an example of a thinning process procedure of the drawing apparatus 100. FIG. 8 is a flowchart illustrating an example of the surface deletion processing procedure of the drawing apparatus 100.

  Exemplary embodiments of a drawing method, a drawing apparatus, and a drawing program according to the present invention will be described below in detail with reference to the accompanying drawings.

(Specific example of drawing process of drawing apparatus 100)
FIG. 1 is an explanatory diagram illustrating a specific example of the drawing process of the drawing apparatus 100.

  In FIG. 1, a drawing apparatus 100 is a computer that has drawing data of a three-dimensional image, performs a thinning process on the drawing data, and draws a three-dimensional image based on the thinned drawing data. Here, the drawing data is data including a plurality of vertex data representing each of a plurality of meshes forming a three-dimensional image. A mesh is a set of one or more faces. The vertex data is data of the X coordinate value, the Y coordinate value, and the Z coordinate value of the vertex.

  The drawing data is data in which a thinning level of each of a plurality of meshes forming a three-dimensional image is set. The thinning level is data indicating the degree of deletion of vertex data. The thinning level is, for example, a level at which the mesh is not deleted, that is, a level at which the mesh is drawn as it is, a level at which the mesh is deleted, and a level at which the edge common to the two faces included in the mesh is deleted.

  In the following description, the level at which the mesh is not deleted, that is, the mesh is drawn as it is, may be referred to as “level 1”. In the following description, the level at which the mesh is deleted may be referred to as “level 2”. Here, the deletion of the mesh with level 2 set may be always performed, or may be performed only when the area of the mesh is smaller than the threshold value. When there are multiple meshes with level 2 set, all of the multiple meshes may be deleted, some of the multiple meshes may be selected and deleted, or randomly from multiple meshes The selected mesh may be deleted.

  In the following description, a level at which a ridge line common to two surfaces included in a mesh is deleted may be referred to as “level 3”. Here, the deletion of the ridgeline in the mesh for which level 3 is set may be always performed, or may be performed only when the area of the mesh is smaller than the threshold value. When there are multiple meshes with level 3 set, the ridgeline may be deleted from all of the multiple meshes, or a part of the plurality of meshes may be selected and the ridgeline may be deleted. You may delete the edge of the mesh chosen at random from the mesh. Deleting the edge line common to the two faces included in the mesh is called Edge Collapse.

  In the example of FIG. 1, the drawing apparatus 100 performs a thinning process on each of a plurality of meshes forming the three-dimensional image “apple” based on the drawing data of the three-dimensional image “apple”. Here, in order to maintain the shape of the mesh that forms the portion characterizing the shape of the three-dimensional image, the mesh that forms the “leaf” portion of the three-dimensional image “apple” is created by the creator of the drawing data. Level 1 is set as the thinning level.

  In addition, the drawing data creator omits drawing on the mesh that forms the “body” portion of the “apple” in the 3D image in order to omit drawing of the portion that does not characterize the shape of the 3D image. Level 3 is set as the level. Also, level 2 is set as the thinning level for the mesh that forms the “bottom” portion of the three-dimensional image “apple” by the creator of the drawing data.

  For example, the drawing apparatus 100 performs a thinning process on a mesh forming a “leaf” portion of the three-dimensional image “apple”. In this case, the drawing apparatus 100 does not delete the vertex data representing the mesh, since level 1 is set as the mesh thinning level.

  In addition, the drawing apparatus 100 performs, for example, a thinning process on a mesh that forms a “body” portion of the three-dimensional image “apple”. In this case, since the level 3 is set as the thinning level of the mesh, the drawing apparatus 100 deletes the ridge line common to the two surfaces included in the mesh. Here, the drawing apparatus 100 deletes the ridgeline V1-V2 common to the surface C and the surface G. Specifically, the drawing apparatus 100 deletes the vertex data of the vertex V1 and the vertex data of the vertex V2, and adds the vertex data of the intermediate vertex V between the vertex V1 and the vertex V2.

  In addition, the drawing apparatus 100 performs a thinning process on the mesh forming the “bottom surface” portion of the three-dimensional image “apple”. In this case, since level 2 is set as the thinning level of the mesh, the drawing apparatus 100 deletes a plurality of vertex data representing the mesh when the area of the mesh on the display is equal to or smaller than the threshold value.

  As a result, the drawing apparatus 100 can reduce the number of vertex data when drawing the three-dimensional image while maintaining the shape of the three-dimensional image, and improve the drawing efficiency of the three-dimensional image. For this reason, the drawing apparatus 100 can reduce the processing load required for drawing a three-dimensional image and reduce the time required for drawing the three-dimensional image. As a result, the viewer of the three-dimensional image can browse the three-dimensional image without feeling uncomfortable. The drawing apparatus 100 maintains the shape of the 3D image based on the thinning level set for each mesh by the creator of the drawing data of the 3D image. Drawing efficiency can be improved.

  Although the case where the thinning level is set for all the meshes forming the three-dimensional image has been described here, the present invention is not limited to this. For example, there may be a mesh for which a thinning level is not set among meshes forming a three-dimensional image. In this case, for example, the drawing apparatus 100 may treat a mesh for which the thinning level is not set as a mesh for which the thinning level is set to level 1.

  Although the case where the thinning-out level is the level 1 to level 3 described above has been described here, the present invention is not limited to this. For example, the thinning level may include a level for drawing a mesh as a point, that is, a level for leaving one vertex data representing the mesh and deleting other vertex data. The thinning level may include a level for drawing the mesh as a line, that is, a level for deleting other vertex data while leaving two vertex data representing the mesh.

(Hardware configuration example of drawing apparatus 100)
FIG. 2 is a block diagram illustrating a hardware configuration example of the drawing apparatus 100 according to the embodiment. In FIG. 2, a drawing apparatus 100 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, a graphics subsystem (Graphics Subsystem) 204, and a display 205. Have. Each component is connected by a bus 200.

  Here, the CPU 201 controls the entire drawing apparatus 100. The ROM 202 stores a program such as a boot program. The ROM 202 stores three-dimensional image drawing data. The RAM 203 is used as a work area for the CPU 201.

  The graphics subsystem 204 is a series of systems for displaying images on the display 205. The graphics subsystem 204 includes a three-dimensional engine (Three-Dimensional Engine) 206, a VRAM 207, and a display controller (Display Controller) 208.

  The three-dimensional engine 206 converts drawing data of the three-dimensional image into display data for the display 205 and stores it in the VRAM 207. The VRAM 207 stores display data for the display 205. The display controller 208 reads display data from the VRAM 207, converts it into a video signal, and supplies it to the display 205.

  The display 205 displays a three-dimensional image. The display 205 displays data such as a document, an image, and function information as well as a cursor, an icon, or a tool box. As the display 205, for example, a liquid crystal display, a plasma display, or the like can be adopted. The drawing apparatus 100 may further include at least one of a magnetic disk drive, a keyboard, a mouse, a scanner, and a printer.

(Data structure of drawing data 300)
Next, an example of the data structure of the drawing data 300 will be described with reference to FIG. The drawing data 300 is stored in, for example, the RAM 203 shown in FIG. A specific example of the drawing data 300 will be described later with reference to FIG.

  FIG. 3 is an explanatory diagram showing an example of the data structure of the drawing data 300. As shown in FIG. 3, the drawing data 300 includes data 301 for the maximum number of meshes. Here, the maximum number of meshes is the number of meshes that form a three-dimensional image. In addition, the drawing data 300 includes as many mesh data as the number of meshes. The mesh data includes data 302 on the number of vertices in the mesh. Here, the number of vertices in the mesh is the number of vertices representing the mesh. Further, the mesh data includes thinning level data 303.

  Further, the mesh data has vertex data corresponding to the number of vertices. The vertex data includes X coordinate value data 304, Y coordinate value data 305, and Z coordinate value data 306. Here, the X coordinate value is the coordinate value of the X axis among the coordinate values of the vertices representing the mesh. The Y coordinate value is the coordinate value of the Y axis among the coordinate values of the vertices representing the mesh. The Z coordinate value is a coordinate value of the Z axis among the coordinate values of the vertices representing the mesh.

(Functional configuration example of the drawing apparatus 100)
Next, a functional configuration example of the drawing apparatus 100 will be described with reference to FIG. FIG. 4 is a block diagram illustrating a functional configuration example of the drawing apparatus 100. The drawing apparatus 100 includes a thinning unit 401 and a drawing unit 402. The thinning unit 401 and the drawing unit 402 realize their functions by causing the CPU 201 to execute a program stored in a storage device such as the ROM 202 and the RAM 203 illustrated in FIG.

  The thinning unit 401 performs a thinning process on the mesh according to a thinning level that is set for the mesh forming the three-dimensional image and indicates the degree of deletion of a plurality of vertex data representing the mesh. The thinning unit 401 performs thinning processing on the mesh depending on, for example, whether the mesh thinning level is the level 1, level 2, or level 3 described above.

  As described above, level 1 is a level at which a mesh is drawn as it is without deleting a plurality of vertex data representing the mesh. Level 2 is a level at which a plurality of vertex data representing a mesh is deleted as described above. Level 3 is a level at which a ridge line common to two surfaces included in the mesh is deleted as described above.

  In the following description, the thinning process performed on the mesh when the mesh thinning level is the level 1 described above may be referred to as “first thinning process”. In the following description, the thinning process performed on the mesh when the mesh thinning level is the level 2 described above may be referred to as “second thinning process”. In the following description, the thinning process performed on the mesh when the mesh thinning level is the level 3 described above may be referred to as “third thinning process”.

<First thinning process>
When the mesh thinning level is level 1, the thinning unit 401 leaves a plurality of vertex data representing the mesh. For example, the thinning unit 401 reads the drawing data 300 from the ROM 202, and the data of the number of vertices in the mesh, the data of the X coordinate value, the data of the Y coordinate value, and the Z coordinate value of the duplicate data of the read drawing data 300 Keep the data. Thereby, the thinning unit 401 can maintain the shape of the three-dimensional image.

<Second thinning process>
When the mesh thinning level is level 2, the thinning unit 401 deletes a plurality of vertex data. For example, the thinning unit 401 reads the drawing data 300 from the ROM 202, and the data of the number of vertices in the mesh, the data of the X coordinate value, the data of the Y coordinate value, and the Z coordinate value of the duplicate data of the read drawing data 300 Delete the data. Thereby, the thinning-out part 401 can reduce the number of vertex data at the time of drawing a three-dimensional image, and can improve the drawing efficiency of a three-dimensional image.

  Further, the thinning unit 401 may calculate the area of the mesh on the display screen, and when the area is equal to or smaller than the threshold and the mesh thinning level is level 2, the plurality of vertex data may be deleted. The thinning unit 401 calculates the area of the mesh on the display screen. If the area is not equal to or less than the threshold and the mesh thinning level is level 2, the plurality of vertex data is not deleted. Thereby, the thinning-out part 401 can reduce the number of vertex data at the time of drawing a three-dimensional image, and can improve the drawing efficiency of a three-dimensional image.

<Third decimation process>
When the mesh thinning level is level 3, the thinning unit 401 deletes two vertex data serving as end points of the ridge line among the plurality of vertex data, and adds vertex data indicating the middle of the two vertex data. For example, the thinning unit 401 reads the drawing data 300 from the ROM 202, calculates the average value of the coordinate values of the two vertex data serving as the end points of the ridge line in the copied data of the read drawing data 300, and creates a new value. Create and add vertex data. Also, the thinning unit 401 deletes the two vertex data. Thereby, the thinning-out part 401 can reduce the number of vertex data at the time of drawing a three-dimensional image, and can improve the drawing efficiency of a three-dimensional image. The thinned vertex data is stored in a storage area such as the RAM 203, for example.

  The drawing unit 402 performs a three-dimensional image drawing process based on the vertex data of the thinned mesh. The drawing unit 402 uses the graphics subsystem 204 to draw a three-dimensional image on the display 205 based on the thinned three-dimensional image drawing data 300. Accordingly, the drawing unit 402 can draw a three-dimensional image on the display 205 and allow the viewer to view the three-dimensional image.

(Contents of drawing process of drawing apparatus 100)
Next, the contents of the drawing process of the drawing apparatus 100 will be described with reference to FIG.

  FIG. 5 is an explanatory diagram showing the contents of the drawing process of the drawing apparatus 100. In FIG. 5, the drawing apparatus 100 reads the drawing data 300 before the thinning process from the ROM 202. Here, the original drawing data 300 remains in the ROM 202.

  In the example of FIG. 5, copy data of the read drawing data 300 is set as drawing data 501 before the thinning process. The drawing data 501 before the thinning process includes mesh 1 data, mesh 2 data, and mesh 3 data.

  The data of mesh 1 includes a thinning level “level 2”. Further, the data of mesh 1 includes three vertex data. The three vertex data of the mesh 1 are data indicating coordinate values (−0.9, 0.6928, 0), data indicating coordinate values (−0.9, −0.6928, 0), and coordinate values. This is data indicating (-1, 0, 0).

  The data of the mesh 2 includes a thinning level “level 1”. Further, the data of mesh 2 includes three vertex data. The three vertex data of the mesh 2 are data indicating coordinate values (−0.8, 0.6928, 0), data indicating coordinate values (−0.8, −0.6928, 0), and coordinate values. Data indicating (0.6, 0, 0).

  The data of the mesh 3 includes a thinning level “level 3”. The data of mesh 3 includes 10 vertex data. Ten vertex data of the mesh 3 are data indicating coordinate values (0.928, −0.04754,0), data indicating coordinate values (0.679, −0.17241,0),... And coordinate values (0.973, −0.61348, 0).

  The drawing apparatus 100 deletes the data of the mesh 1 because the thinning level of the mesh 1 is level 2. The drawing apparatus 100 does not delete the data of the mesh 2 because the thinning level is level 1 for the mesh 2.

  Since the thinning level is level 3 for the mesh 3, the drawing apparatus 100 identifies two vertex data that are the end points of the ridge line among the ten vertex data. Here, the drawing apparatus 100 uses, as two vertex data, data indicating the coordinate value (0.948, −0.2894, 0) on the end side and the coordinate value (0.973, −0.61348, 0). And data indicating that.

  Next, the drawing apparatus 100 calculates an average value of each coordinate value of the specified data, creates vertex data (0.96, −0.45144, 0) indicating the middle, and adds it. In this manner, the drawing apparatus converts the drawing data 501 before the thinning process into the drawing data 502 after the thinning process.

  As a result, the drawing apparatus 100 can reduce the number of vertex data when drawing the three-dimensional image while maintaining the shape of the three-dimensional image, and improve the drawing efficiency of the three-dimensional image. For this reason, the drawing apparatus 100 can reduce the processing load required for drawing a three-dimensional image and reduce the time required for drawing the three-dimensional image. As a result, the viewer of the three-dimensional image can browse the three-dimensional image without feeling uncomfortable. The drawing apparatus 100 maintains the shape of the 3D image based on the thinning level set for each mesh by the creator of the drawing data of the 3D image. Drawing efficiency can be improved.

(Example of drawing processing procedure of drawing apparatus 100)
Next, an example of a drawing process procedure of the drawing apparatus 100 will be described with reference to FIG.

  FIG. 6 is a flowchart illustrating an example of a drawing processing procedure of the drawing apparatus 100. As illustrated in FIG. 6, the drawing apparatus 100 reads the drawing data 300 stored in the ROM 202, and extracts the maximum number of meshes from the read drawing data 300 (step S601).

  Next, the drawing apparatus 100 substitutes the extracted maximum number of meshes for the variable MESH_MAX, and substitutes the extracted maximum number of meshes for the variable NEW_MESH_MAX (step S602). Then, the drawing apparatus 100 substitutes 1 for the variable n (step S603).

  Next, the drawing apparatus 100 extracts an nth mesh thinning level from the read drawing data 300 (step S604). Then, the drawing apparatus 100 performs a thinning process which will be described later with reference to FIG. 7 (step S605).

  Next, the drawing apparatus 100 substitutes n + 1 for the variable n (step S606). Then, the drawing apparatus 100 determines whether n is larger than MESH_MAX (step S607). Here, when it is equal to or less than MESH_MAX (step S607: No), the drawing apparatus 100 returns to the process of step S604.

  On the other hand, when larger than MESH_MAX (step S607: Yes), the drawing apparatus 100 overwrites NEW_MESH_MAX with the maximum number of meshes of the drawing data 300 subjected to the thinning process (step S608).

  Next, the drawing apparatus 100 substitutes 1 for the variable n (step S609). Then, the drawing apparatus 100 draws the n-th mesh of the thinned drawing data 300 (step S610). Next, the drawing apparatus 100 substitutes n + 1 for the variable n (step S611). Then, the drawing apparatus 100 determines whether n is larger than NEW_MESH_MAX (step S612). Here, when it is below NEW_MESH_MAX (step S612: No), the drawing apparatus 100 returns to the process of step S610.

  On the other hand, when larger than NEW_MESH_MAX (step S612: Yes), the drawing apparatus 100 ends the drawing process. Accordingly, the drawing unit 402 can draw a three-dimensional image on the display 205 and allow the viewer to view the three-dimensional image.

(Example of thinning process procedure of the drawing apparatus 100)
Next, an example of the thinning process procedure of the drawing apparatus 100 shown in step S605 will be described with reference to FIG.

  FIG. 7 is a flowchart illustrating an example of a thinning process procedure of the drawing apparatus 100. As shown in FIG. 7, the drawing apparatus 100 determines some thinning levels (step S701). If the thinning level is level 1 (step S701: level 1), the drawing apparatus 100 stores the mesh data as it is in the RAM 203 (step S702), and ends the thinning process.

  On the other hand, when the thinning level is level 2 (step S701: level 2), the drawing apparatus 100 calculates the area of the mesh (step S703). Next, the drawing apparatus 100 determines whether or not the area is equal to or less than the threshold value (step S704).

  Here, when larger than a threshold value (step S704: No), the drawing apparatus 100 transfers to the process of step S702. On the other hand, if it is equal to or less than the threshold (step S704: Yes), the drawing apparatus 100 does not store the mesh data in the RAM 203 (step S705), and substitutes NEW_MESH_MAX-1 for the variable NEW_MESH_MAX (step S706). Then, the drawing apparatus 100 ends the thinning process.

  In step S701, when the thinning level is level 3 (step S701: level 3), the drawing apparatus 100 performs a surface deletion process, which will be described later with reference to FIG. 8 (step S707), and ends the thinning process. As a result, the drawing apparatus 100 can reduce the number of vertex data when drawing the three-dimensional image while maintaining the shape of the three-dimensional image, and improve the drawing efficiency of the three-dimensional image.

(An example of the surface deletion processing procedure of the drawing apparatus 100)
Next, an example of the surface deletion processing procedure of the drawing apparatus 100 shown in step S707 will be described with reference to FIG.

  FIG. 8 is a flowchart illustrating an example of the surface deletion processing procedure of the drawing apparatus 100. As illustrated in FIG. 8, the drawing apparatus 100 registers edge points of ridge lines as vertex pairs to which a QEM (Quadric Error Metrics) method is applied (step S801). Since the QEM technique is a conventional technique, a detailed description thereof will be omitted.

  Next, the drawing apparatus 100 calculates a 4 × 4 matrix from the polygons that share the registered vertex pairs (step S802). Then, the drawing apparatus 100 calculates a cost for each vertex pair based on the matrix (step S803).

  Next, the drawing apparatus 100 calculates the coordinate value of the degenerated vertex obtained by degenerating the vertex pair (step S804). Then, the drawing apparatus 100 deletes the vertex pair having the minimum cost, and adds the coordinate value of the degenerate vertex calculated for the vertex pair having the minimum cost (step S805).

  Next, the drawing apparatus 100 determines whether or not the number of faces included in the mesh is equal to or less than a predetermined number (step S806). Here, when larger than the predetermined number (step S806: No), the drawing apparatus 100 specifies the vertex pair after adding the coordinate value of the degenerate vertex, calculates the cost of the vertex pair (step S807), and step The process returns to S805.

  On the other hand, if the number is equal to or less than the predetermined number (step S806: Yes), the drawing apparatus 100 stores the data of the mesh to which the coordinate value of the degenerate vertex is added in the RAM 203 (step S808), and ends the surface deletion process.

  As described above, according to the drawing method, it is possible to perform the thinning process on the mesh according to the thinning level set for the mesh forming the three-dimensional image. Thereby, the drawing method can reduce the number of vertex data when drawing the 3D image while maintaining the shape of the 3D image, and can improve the drawing efficiency of the 3D image. For this reason, the drawing apparatus 100 can reduce the processing load required for drawing a three-dimensional image and reduce the time required for drawing the three-dimensional image. As a result, the viewer of the three-dimensional image can browse the three-dimensional image without feeling uncomfortable. The drawing apparatus 100 maintains the shape of the 3D image based on the thinning level set for each mesh by the creator of the drawing data of the 3D image. Drawing efficiency can be improved.

  Also, according to the drawing method, when the drawing level is level 2, a plurality of vertex data representing the mesh can be deleted. Thereby, the drawing method can reduce the number of vertex data when drawing the 3D image while maintaining the shape of the 3D image, and can improve the drawing efficiency of the 3D image.

  Further, according to the drawing method, when the mesh area is equal to or smaller than the threshold and the drawing level is level 2, a plurality of vertex data representing the mesh can be deleted. As a result, the drawing method can draw the mesh when the area of the mesh is large and the viewer can feel uncomfortable without drawing the mesh. On the other hand, if the drawing method does not give the viewer a sense of incongruity even if the mesh is not drawn because the mesh area is small, the vertex when drawing the 3D image while maintaining the shape of the 3D image It is possible to reduce the number of data and improve the drawing efficiency of the three-dimensional image.

  Also, according to the drawing method, when the drawing level is level 3, the vertex data between the two vertex data that are the end points of the ridgeline common to the two faces included in the mesh is created, and the two vertex data are deleted can do. Thereby, the drawing method can reduce the number of vertex data when drawing the 3D image while maintaining the shape of the 3D image, and can improve the drawing efficiency of the 3D image.

  The drawing method described in the present embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. The drawing program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The drawing program may be distributed through a network such as the Internet.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1)
According to the thinning level indicating the degree of deletion of a plurality of vertex data representing the mesh set in the mesh forming the three-dimensional image, the thinning process is performed on the mesh,
Based on the vertex data of the mesh subjected to the thinning process, the three-dimensional image is drawn.
A drawing method characterized by executing processing.

(Supplementary note 2) In the supplementary note 1, the process of performing the thinning process deletes the plurality of vertex data when the mesh thinning level is a level indicating that the plurality of vertex data is deleted. The drawing method described.

(Supplementary note 3)
Execute the process of calculating the area of the mesh on the display screen,
The thinning process is a level indicating that the mesh thinning level is to delete the plurality of vertex data, and when the area is equal to or less than a threshold value, the plurality of vertex data is deleted. The drawing method according to Appendix 2.

(Additional remark 4) The process which performs the said thinning-out process is a level which shows that the said thinning-out level of the mesh deletes these several vertex data, However, When the said area is not below a threshold value, the said several vertex data are not deleted The drawing method according to Supplementary Note 3, wherein

(Additional remark 5) When the process which performs the said thinning-out process is a level which shows deleting the ridgeline common to two surfaces contained in the said mesh, the said thinning-out process WHEREIN: Of the said some vertex data The drawing method according to any one of appendices 1 to 4, wherein two vertex data serving as end points of the ridge line are deleted, and vertex data indicating an intermediate point between the two vertex data is added.

(Additional remark 6) The process which performs the said thinning process WHEREIN: When the said thinning-out level is a level which shows not deleting the said several vertex data, the said several vertex data are not deleted 6. The drawing method according to any one of 5 above.

(Additional remark 7) The process which performs the said thinning process performs the thinning process with respect to the said mesh according to the thinning level which shows the deletion degree of the some vertex data showing the said mesh set for every mesh which forms the three-dimensional image. Done
The drawing processing according to any one of appendices 1 to 6, wherein the drawing processing performs drawing processing of the three-dimensional image based on the vertex data for each mesh subjected to the thinning processing. Method.

(Supplementary Note 8) A thinning unit that performs a thinning process on the mesh according to a thinning level that is set for a mesh that forms a three-dimensional image and indicates a degree of deletion of a plurality of vertex data representing the mesh;
A drawing unit that performs drawing processing of the three-dimensional image based on the vertex data of the mesh subjected to the thinning-out process;
A drawing apparatus comprising:

(Appendix 9)
According to the thinning level indicating the degree of deletion of a plurality of vertex data representing the mesh set in the mesh forming the three-dimensional image, the thinning process is performed on the mesh,
Based on the vertex data of the mesh subjected to the thinning process, the three-dimensional image is drawn.
A drawing program for executing a process.

DESCRIPTION OF SYMBOLS 100 Drawing apparatus 401 Thinning part 402 Drawing part

Claims (8)

Computer
A three-dimensional image is set in mesh form, a decimation level indicating deletion degree of a plurality of vertex data representing the mesh, depending on the area of the mesh on the display screen, a plurality of vertex data representing the mesh Thinning out
Based on the vertex data of the mesh subjected to the thinning process, the three-dimensional image is drawn.
A drawing method characterized by executing processing.   The drawing according to claim 1, wherein the thinning process deletes the plurality of vertex data when the thinning level of the mesh is a level indicating that the plurality of vertex data is deleted. Method. The computer is
Execute the process of calculating the area of the mesh on the display screen,
The thinning process is a level indicating that the mesh thinning level is to delete the plurality of vertex data, and when the area is equal to or less than a threshold value, the plurality of vertex data is deleted. The drawing method according to claim 2.   The thinning process is a level indicating that the mesh thinning level is to delete the plurality of vertex data, but the plurality of vertex data is not deleted if the area is not equal to or less than a threshold value. The drawing method according to claim 3.   When the thinning level of the mesh is a level indicating that a ridge line common to two faces included in the mesh is deleted, the process of performing the thinning process includes the end point of the ridge line of the plurality of vertex data, 5. The drawing method according to claim 1, wherein the two vertex data are deleted and vertex data indicating an intermediate point between the two vertex data is added.   The process of performing the thinning-out process does not delete the plurality of vertex data when the thinning-out level of the mesh is a level indicating that the plurality of vertex data is not deleted. The drawing method as described in one. A three-dimensional image is set in mesh form, a decimation level indicating deletion degree of a plurality of vertex data representing the mesh, depending on the area of the mesh on the display screen, a plurality of vertex data representing the mesh A thinning unit for performing a thinning process on
A drawing unit that performs drawing processing of the three-dimensional image based on the vertex data of the mesh subjected to the thinning-out process;
A drawing apparatus comprising: On the computer,
A three-dimensional image is set in mesh form, a decimation level indicating deletion degree of a plurality of vertex data representing the mesh, depending on the area of the mesh on the display screen, a plurality of vertex data representing the mesh Thinning out
Based on the vertex data of the mesh subjected to the thinning process, the three-dimensional image is drawn.
A drawing program for executing a process.

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