KR101551741B1 - Method for Configuring Vertex of Three-dimensional Object Model - Google Patents

Abstract

The present invention relates to a method for configuring vertices of a three-dimensional object model and, more particularly to a method for configuring vertices of a three-dimensional object model which is performed by a three-dimensional rendering processing device for expressing three-dimensional object data including buildings on a three-dimensional map. The present invention may include the steps of: modeling three-dimensional object data existing on a three-dimensional map as at least one polygon; by analyzing the polygons with respect to the three-dimensional object data, extracting vertex information including spatial coordinates configuring the shape of the polygons or index information including the order required for the polygon expression of the vertex, and storing the information as vertex-index information; calculating the three-dimensional distance between vertices based on the index information, and determining multiple vertices, whose three-dimensional distance is equal to or less than a reference distance, as overlapped vertices; and modifying the index information with respect to one vertex among the overlapped vertices, and removing the pertinent vertex from the vertex-index information. Therefore, the present invention can express the three-dimensional object data with a minimum of vertices by removing the overlapped vertices when configuring the vertices of the three-dimensional object data and by using the vertex-index information with the minimized vertices; and can reduce screen processing time, storage capacity, and network transmission speed of the data by minimizing the data while maintaining the shape of the three-dimensional object data with the optimized vertices.

Description

A method for constructing a vertex of a three-dimensional object model {Method for Configuring Vertex of Three-dimensional Object Model}

The present invention relates to a method of constructing a vertex of a three-dimensional object model, and more particularly, to a method of constructing a vertex of a three-dimensional object model by using vertex-index information minimizing overlapping vertices when authoring three- And to a method for constructing a vertex of an object model.

Most car and portable navigation devices rely on a two-dimensional navigation map to visualize key features, such as buildings, in 2D, but a three-dimensional vehicle navigation system is emerging. Most of these 3D navigation systems use photorealistic rendering techniques to visualize 3D building data.

This visualization technique based on realistic rendering requires accurate geometric models and detailed realistic building textures, and it is necessary to match the rendered 3D buildings, roads or other objects with actual buildings, roads or other objects as closely as possible have.

A three-dimensional mesh (Mesh) refers to a bundle of data, such as a point, a plane, used to represent an object in three dimensions on a graphical basis. These three-dimensional meshes are widely applied to various applications representing three-dimensional objects. The three-dimensional mesh consists of triangles made up of vertices and three vertices, and these triangles are gathered to complete one complete mesh.

In real life, in order to express a building in three dimensions, the information of a triangle is connected to one another in a complicated shape. At this time, in the case of a building in which a three-dimensional object is shielded from an inner space and an outer space, at least one vertex of a triangle formed by three vertices overlaps with another vertex of another triangle.

Therefore, when a building or other object is simply represented by a triangle on a three-dimensional map, the number of vertices is fixed at three times the number of triangles because no overlapping vertex is considered.

1 is a block diagram illustrating a basic data format for vertices of three-dimensional building data.

Referring to FIG. 1, one vertex in 3D building data is composed of 20 bytes, which is a floating-point format having 4 bytes (Byte), and includes position coordinate information of x, y and z and texture coordinate information of u and v , And the index information is composed of 2 bytes.

For example, when three-dimensional building data consists of 10,000 triangles, in order to represent the building data as a triangle, the capacity of the entire vertex is 20 bytes (one vertex capacity) × 3 × 1 (the number of triangles) That is, 600,000 bytes are required.

As a prior art data, a method of encoding and decoding connection information of a 3D data implemented in a mesh model disclosed in Korean Patent Laid-Open No. 10-2009-0097057 uses a distance characteristic of vertices included in a polygon, .

To this end, in the prior art, a gate including first and second vertices serving as a reference for connection information of a polygon to be encoded is selected based on vertex information included in the geometric data, The method comprising the steps of: acquiring information about a distance relation between a point included in a gate and at least one candidate point after setting at least one point around the point as a candidate point; And the connection information of the points of < RTI ID = 0.0 >

That is, the prior art compresses and encodes the connection information included in the three-dimensional data represented by the mesh model, and the connection information and the geometry data are separately compressed by a general three-dimensional compression algorithm. At this time, the geometric data is compressed using a high correlation between positions of adjacent vertices according to the coding order determined by the coding of the connection information. That is, most geometric compression schemes follow quantization of vertex positions, prediction of quantized positions, and entropy coding of prediction residues.

In this way, according to the prior art, since data is compressed using the distance characteristic of the vertexes constituting the polygon, some of the vertices of the polygon may overlap with each other depending on automation or skill of the operator, There is a problem in that data capacity for compressing increases and data transfer, data storage and data throughput increase as the number of three-dimensional buildings to be expressed on a three-dimensional map increases.

Therefore, unless the phenomenon that the vertexes of the polygons overlap each other in the representation of the three-dimensional object data is removed, the data capacity to be processed in real time is increased as much as the number of overlapping points, and the amount of memory for the three- There is a problem that time required for three-dimensional object representation and data can be wasted because complex calculation process is required in compression and restoration as well as a large amount of data processing is required.

Korean Patent Laid-Open No. 10-2009-0097057 entitled " Coding and Decoding Method of Connection Information of 3D Data Implemented by Mesh Model "

The present invention constitutes vertex-index information which is obtained by optimizing vertices by eliminating overlapping vertexes when constructing vertexes of three-dimensional object data. In addition, And provides a vertex construction method of a three-dimensional object model that can lighten data while retaining the appearance of the three-dimensional object data at the minimum vertex.

Among the embodiments, a vertex construction method of a three-dimensional object model includes a vertex construction method of a three-dimensional object model performed by a three-dimensional rendering processor for representing three-dimensional object data including a building on a three-dimensional map Modeling the three-dimensional object data existing on the three-dimensional map into at least one polygon; And extracting index information including vertex information including a spatial coordinate point constituting the shape of the polygon and order necessary for polygon representation of the vertex through analysis of polygons with respect to the 3D object data, Storing information as information; Calculating a three-dimensional distance between the vertices based on the index information, and determining the plurality of vertices corresponding to the three-dimensional distance less than the reference distance as overlapping vertices; And removing the corresponding vertex from the vertex-index information after modifying the index information of any of the vertices of the overlapping vertex.

The vertex information is characterized by inserting characteristic information including at least one of color information of a vertex, normal information of a vertex, texture information of a vertex, auxiliary texture information of a vertex, and tangent information of a vertex.

Wherein the step of calculating the three-dimensional distance between the vertices based on the index information and determining the plurality of vertices having the three-dimensional distance equal to or less than the reference distance as the overlapped vertices comprises: One vertex is selected as a reference point according to a storage order of the index information, and a vertex corresponding to the next order of the selected vertex is designated as a comparison point.

Wherein the step of removing the vertex from the vertex-index information after modifying the index information of the vertex corresponding to the overlapped vertex is performed by changing the index information of the comparison point to the index information of the reference point, And the vertex information and the index information corresponding to the comparison point are removed from the index information.

The method of constructing a vertex of a three-dimensional object model of the present invention can represent three-dimensional object data as a minimum vertex by using vertex-index information that is obtained by removing vertices that are overlapped when constructing vertices of three-dimensional object data , It is possible to reduce the network transmission speed, the storage capacity, and the screen processing time of the data by making the data lightweight while maintaining the appearance of the three-dimensional object data at the minimum vertex.

In addition, the present invention can quickly render vertex-index information from which redundant vertices have been removed, optimize vertex-related data that is wasted by authoring automation of the 3D object data or skill or error of the operator, The load of the system using the object data can be reduced.

1 is a block diagram illustrating a basic data format for vertices of three-dimensional building data.
2 is a block diagram illustrating a 3D rendering processor according to an embodiment of the present invention.
3 is a flowchart illustrating a method of constructing a vertex of a 3D object model according to an embodiment of the present invention.
FIG. 4 is a diagram for explaining an expanded state of a polygon model for three-dimensional object data according to an embodiment of the present invention.
5 is a view for explaining vertex information and index information in FIG.
FIG. 6 is a view for explaining a process of determining the overlapped vertex position among the vertices of the polygon of FIG.
FIG. 7 is a view for explaining a list of all vertices for overlapping vertices identified by FIG. 6. FIG.
FIG. 8 is a diagram for explaining a process of removing vertices and correcting index information for the overlapping vertices of FIG. 7. FIG.
FIG. 9 is a diagram for comparing a list of pre-removal vertices of redundant vertices and a list of vertices after duplicate vertex removal according to an embodiment of the present invention.
10 is a diagram for explaining an expanded state of a polygon model after eliminating overlapping vertexes according to an embodiment of the present invention.

The description of the present invention is merely an example for structural or functional explanation, and the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, the embodiments are to be construed as being variously embodied and having various forms, so that the scope of the present invention should be understood to include equivalents capable of realizing technical ideas. Also, the purpose or effect of the present invention should not be construed as limiting the scope of the present invention, since it does not mean that a specific embodiment should include all or only such effect.

Meanwhile, the meaning of the terms described in the present invention should be understood as follows.

The terms "first "," second ", and the like are intended to distinguish one element from another, and the scope of the right should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element, but there may be other elements in between. On the other hand, when an element is referred to as being "directly connected" to another element, it should be understood that there are no other elements in between. On the other hand, other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

It should be understood that the singular " include "or" have "are to be construed as including a stated feature, number, step, operation, component, It is to be understood that the combination is intended to specify that it does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

In each step, the identification code (e.g., a, b, c, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, Unless otherwise stated, it may occur differently from the stated order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used predefined terms should be interpreted to be consistent with the meanings in the context of the related art and can not be interpreted as having ideal or overly formal meaning unless explicitly defined in the present invention.

2 is a block diagram illustrating a 3D rendering processor according to an embodiment of the present invention.

Referring to FIG. 2, a 3D rendering apparatus 100 for representing 3D object data including a building on a 3D map includes a mesh modeling module 110, a vertex optimization module 120, a rendering module 130, A control module 140 and a storage module 150.

The mesh modeling module 110 extracts a plurality of three-dimensional object data existing on the three-dimensional map, and models the triangular polygons for each three-dimensional object data.

 The vertex optimization module 120 extracts vertex information including a spatial coordinate point constituting the shape of the polygon and index information including a sequence necessary for the polygon representation of the vertices through the analysis of the polygons, , And the vertex optimization process is performed by comparing each vertex sequentially to check whether there is a redundant vertex.

The rendering module 130 aligns the plurality of polygons using the vertex-index information through the vertex optimization module 120, and sequentially renders the plurality of aligned polygons.

The control module 140 controls operations of the mesh modeling module 110, the vertex optimization module 120, and the rendering module 130 to reconstruct vertex-index information so that the vertices of the three-dimensional object data are optimized.

The storage module 150 stores three-dimensional object data, polygon modeling information for each three-dimensional object data, and vertex-index information required for vertex optimization.

Here, each of the modules 110 to 150 may be designed in the form of hardware or software, or may be designed by integrating hardware and software.

FIG. 3 is a flowchart for explaining a method of constructing a vertex of a 3D object model according to an embodiment of the present invention. FIG. 4 is a view for explaining a developed state of a polygon model for 3D object data according to an embodiment of the present invention FIG. 5 is a view for explaining the vertex information and the index information of FIG. 4, FIG. 6 is a view for explaining a process of identifying the overlapping vertex position among vertices of the polygon of FIG. 4, and FIG. FIG. 8 is a view for explaining a process of removing vertices and correcting index information for the overlapping vertices of FIG. 7, and FIG. 9 is a view for explaining a process of removing vertices and correcting index information according to an embodiment of the present invention. FIG. 10 is a view for explaining an expanded state of a polygon model after elimination of a duplicate vertex according to an embodiment of the present invention. FIG. A.

3 to 10, a vertex construction method of a three-dimensional object model includes extracting all three-dimensional object data existing on a three-dimensional map, extracting each three-dimensional object data from at least one Model with triangular polygons (S1 and S2)

The 3D rendering apparatus 100 extracts vertex information and index information through analysis of polygons of the 3D object data and stores the vertex information and the index information in the storage module 150 as vertex- S4)

Here, the vertex is a normalized spatial coordinate point constituting the shape of the polygon, and the index can be an order list drawn when the vertices are drawn on the polygon. At this time, the most basic position coordinate information is included in the vertex information, and the feature information can be further added to each vertex. The 3D rendering apparatus 100 has various effects depending on the feature information at the time of rendering.

The feature information includes color information of a vertex, normal or normal information of a vertex, texture (uv) coordinates corresponding to a vertex, auxiliary texture (uv2) coordinates mainly used in a light map texture, and tangent information of a vertex .

The normal or normal information of a vertex is used to determine the direction in which the vertex belongs. The texture coordinates are the texture maps to the polygons, and the tangential information of the vertices is information that specifies the tangential direction to the vertices. It is used to effect the surface in pixels by using auxiliary textures such as bump matching.

As shown in FIG. 4, the 3D rendering apparatus 100 may be developed into triangular polygon models A, B, C, D, E, and F with respect to specific three-dimensional object data.

In the case of polygon A, there are 20 bytes of A0, A1, and A2 vertices, and there are 2 bytes of indexes idx0, idx1, and idx2 for each vertex. 5, when vertex information and index information for three-dimensional object data are loaded, the vertex list needs 20 bytes x 24 vertices = 480 bytes, and the index list is composed of 2 bytes x 24 Index = 48 bytes is required.

As shown in FIG. 5, the 3D rendering apparatus 100 can check the positions of overlapping vertices by analyzing all the polygons of the 3D object data. That is, it can be seen that the vertices of A0-B0, B2-C0, C2-D2, D1-E2, E1-F1 and A2-B1-C1-D0-E0-F2 overlap.

That is, the 3D rendering apparatus 100 selects one vertex as a reference point (A0 (s, y, z) vertex) according to the index order of the index information or the order of storing vertex-index information, The vertex is selected as the comparison point B0 (x ', y', z '). (S5)

The 3D rendering apparatus 100 calculates the 3D distance D1 between the reference point and the comparison point as shown in FIG. 6, and when the 3D distance is less than the reference distance D _ref , (A0 = B0) where the vertex and the B vertex are located at the same position (S6, S7, S8). Here, the reference distance is set to 1 mm, but the reference distance can be adjusted by the operator.

The 3D rendering apparatus 100 replaces the index information idx3 of the B0 vertex, which is the comparison point, with the index information idx0 of the A0 vertex and removes the B0 vertex from the vertex-index information, as shown in FIG. Therefore, the A0 vertex is integrated with the information of the B0 vertex and updated to the P0 vertex (A0 = B0) (S9)

In this manner, the 3D rendering apparatus 100 performs a redundant vertex checking process for all vertices, modifies the index information when there is a redundant vertex, and detects any one of the redundant vertices as the vertex-index information Lt; / RTI >

When the duplicate vertex checking process is completed up to the 24th vertex, which is the last order, the vertex-index information from which the duplicate vertex is removed is output as the final result. That is, as shown in FIGS. 9 and 10, the 3D rendering apparatus 100 includes overlapping vertices A0-B0? P0, B2-C0? P2, C2-D2? P5, D1- , E1-F1? P7 and A2-B1-C1-D0-E0-F2? P3 so that 24 vertices can be represented by 8 vertices and the capacity of the vertices of the 3-dimensional object data is changed from 480 bytes to 160 Lt; / RTI > bytes.

As described above, the method of constructing a vertex of a three-dimensional object model according to an embodiment of the present invention includes vertically-vertex-optimized vertex- It is possible to render the 3-dimensional object data by the vertex-index information quickly, thereby reducing the amount of data required for the vertex construction by 1/3, so that the data transmission time, storage capacity, Can be reduced.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

110: mesh modeling module 120: vertex optimization module
130: rendering module 140: control module
150: storage module

Claims (4)

A method for constructing a vertex of a three-dimensional object model performed by a three-dimensional rendering processor for representing three-dimensional object data including a building on a three-dimensional map,
Dimensionally modeling three-dimensional object data existing on a three-dimensional map into at least one polygon;
And extracting index information including vertex information including a spatial coordinate point constituting the shape of the polygon and order necessary for polygon representation of the vertex through analysis of polygons with respect to the 3D object data, Storing information as information;
Calculating a three-dimensional distance between the vertices based on the index information, and determining the plurality of vertices corresponding to the three-dimensional distance less than the reference distance as overlapping vertices; And
And removing the vertex from the vertex-index information after modifying the index information of any one of the vertices of the overlapping vertex.
The method according to claim 1,
Wherein the vertex information includes at least one characteristic information including at least one of vertex color information, vertex normal information, vertex texture information, vertex auxiliary texture information, and vertex tangent information. How to construct vertices in an object model.
The method according to claim 1,
Calculating a three-dimensional distance between the vertices based on the index information, and determining the plurality of vertices having the three-dimensional distance equal to or less than the reference distance as the overlapped vertices,
And a vertex corresponding to a next vertex of the selected vertex is designated as a comparison point, wherein the vertex of the selected vertex is selected as a reference point according to the indexing order of the index information or the order of storing the vertex- .
The method of claim 3,
Wherein the step of removing the vertex from the vertex-index information after modifying the index information of the vertex corresponding to the overlapped vertex,
The vertex information of the vertices corresponding to the comparison point and the index information are removed from the vertex-index information by changing the index information of the comparison point to the index information of the reference point, .

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