CN114565718B - BIM model face reduction method based on vertex normal angle calculation - Google Patents
BIM model face reduction method based on vertex normal angle calculation Download PDFInfo
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Abstract
The invention discloses a BIM model face reduction method based on vertex normal angle calculation, which optimizes triangular patch data and vertex data of a general BIM model through a mathematical algorithm, fundamentally reduces the triangular patch number and the vertex number of the BIM model and completes light-weight processing of the BIM model data. The invention has the advantages that: the method can calculate and distinguish effective and ineffective surface patches from vertex data according to the BIM model original vertex and the surface patch data and according to the light weight level, and automatically reasonably process the effective and ineffective surface patches and the vertex data, so that the ineffective model primitives are removed, the number of geometric elements of the model is reduced, and the method has the advantages of high automation degree, difficulty in mistakes, high processing speed and the like.
Description
Technical Field
The invention belongs to the technical field of BIM, and particularly relates to a BIM model face reduction method based on vertex normal angle calculation.
Background
With the application and advancement of BIM technology, more and more mass engineering projects use BIM in the whole life cycle to promote the fine management of projects, but due to the limitation of software and hardware resources, the rapid loading and application of mass engineering BIM models is always an industry pain point. Therefore, those skilled in the art have urgent need for a method capable of rapidly loading a BIM model and completing light-weight processing of model data.
Disclosure of Invention
According to the defects of the prior art, the invention provides the BIM model face reduction method based on vertex normal angle calculation, which optimizes triangular patch data and vertex data of a large amount of BIM models through a mathematical algorithm, fundamentally reduces the triangular patch number and the vertex number of the BIM models and completes light-weight processing of the BIM model data.
The invention is realized by the following technical scheme:
the BIM model face reduction method based on vertex normal angle calculation is characterized by comprising the following steps of:
(1) Analyzing and extracting data of the BIM model to obtain geometric basic data of the BIM model, wherein the geometric basic data comprise a vertex array and a triangular patch index array of the BIM model;
(2) Determining a corresponding triangular patch according to the vertex of the BIM model and the triangular patch index, and calculating the normal v of the triangular patch n The calculation method is as follows:
wherein:
v 1 a vector, x, representing one of the edges of the triangular patch 1 、y 1 、z 1 Is vector v 1 Components of (2);
v 2 a vector, x, representing the other edge of the triangular patch 2 、y 2 、z 2 Is vector v 2 Components of (2);
(3) Normal v n Vertex vertexes on the triangular surface patch corresponding to the vertex vertexes m Mapping to obtain the following mapping relation and storing:
wherein: m is 1,2,3, … n;
traversing each vertex on the BIM model m Calculated in vertex m The included angle theta between the triangular patches of the vertex is the included angle set P:
P＝｛θ|θ＝degree(v i ，v j ），v i ∈f -1 (vertex m )，v j ∈f -1 (vertex m )}；
wherein: v i 、v j Is vertex m Normal vector of the triangular patch;
(4) Calculating an included angle threshold epsilon of the triangular patches according to the light weight degree requirement of the BIM model, and screening all included angle sets P' smaller than the included angle threshold epsilon from the included angle sets P:
P′＝{θ′|θ′＜ε}；
(5) Deleting data of triangular patches in the included angle set P', and generating a new vertex array and a triangular patch index array;
(6) Repeating the steps (2) - (5) to finish the face reduction operation of the BIM model.
In step (5), the repeated vertex arrays in the included angle set P' are regenerated into corresponding triangular patch index arrays, and the normal v of each triangular patch is used n The index of the vertex is deduplicated.
The invention has the advantages that: the method can calculate and distinguish effective and ineffective surface patches from vertex data according to the BIM model original vertex and surface patch data and the light weight level, and automatically remove and decrement the effective and ineffective surface patches from vertex data, so that the ineffective model primitives are removed, the number of geometric elements of the model is reduced, and the method has the advantages of high automation degree, difficulty in error, high processing speed and the like.
Drawings
FIG. 1 is a schematic diagram of a BIM model in accordance with the present invention;
FIG. 2 is a schematic diagram of the vertices and normals on a triangular patch according to the present invention;
FIG. 3 is a schematic diagram showing the steps of the BIM model face-subtracting method of the present invention.
Detailed Description
The features of the present invention and other related features are described in further detail below by way of example in conjunction with the following drawings, to facilitate understanding by those skilled in the art:
examples: as shown in fig. 1,2 and 3, the present embodiment specifically relates to a face-subtracting method of a BIM model based on vertex normal angle calculation, and the face-subtracting method of the BIM model optimizes triangular patch data and vertex data of a substantial amount of BIM models through a mathematical algorithm, thereby fundamentally reducing the number of triangular patches and the number of vertices of the BIM models and completing the light-weight processing of the BIM model data, and specifically includes the following steps:
(1) Through each BIM software disclosure API, data analysis and extraction of the BIM model are carried out by using a unified method, bottom data of the BIM model are obtained, the bottom data comprise non-geometric data and geometric data, wherein the non-geometric data comprise project information, attribute information, mapping information and the like, the geometric data comprise vertex array and triangular patch index array data, and the geometric basic data of the BIM model are formed in the form of the vertex array and the triangular patch index array.
(2) On the basis of BIM model geometric basic data, determining a corresponding triangular patch according to a vertex array and a triangular patch index array of the BIM model, and calculating a normal v of the triangular patch n The calculation method is as follows:
wherein:
v 1 vector x representing one of the edges of a triangular patch where the vertex is located 1 、y 1 、z 1 Is vector v 1 Components of (2);
v 2 vector, x, representing the other edge of the triangular patch where the vertex is located 2 、y 2 、z 2 Is vector v 2 Is a component of (a).
(3) The calculated normal v n Vertex vertexes on the triangular surface patch corresponding to the vertex vertexes m Mapping to obtain the following mapping relation and storing:
wherein: m is 1,2,3, … n; here vertex m Respectively three vertexes on the triangular surface patch shown in fig. 2, vertex 1 、vertex 2 、vertex 3 。
Traversing each vertex on BIM model m Calculated in vertex m The included angle theta between the triangular patches of the vertex is the included angle set P:
P＝{θ|θ＝degree(v i ，v j )，v i ∈f -1 (vertex m )，v j ∈f -1 (vertex m )}；
wherein: v i 、v j Is vertex m Normal vector of the triangular patch; .
(4) Calculating an included angle threshold epsilon of the triangular patches according to the light weight degree requirement of the BIM model, and screening all included angle sets P' smaller than the included angle threshold epsilon from the included angle sets P:
P′＝{θ′|θ′＜ε}。
(5) And deleting the data of the triangular patches in the included angle set P', and generating a new vertex array and a new triangular index array.
As shown in fig. 3, the foregoing specific operation of deleting data of the triangular patches in the included angle set P', that is, removing the weight of the vertex normals, the Unity drawing requires that the lengths of the triangular patch index array and the vertex array must be identical, meaning that the normal line of each vertex must be generated according to the triangular patch index, which results in the vertex being repeatedly created, so that the corresponding triangular patch index needs to be regenerated according to the repeated vertex array and the weight of the vertex index needs to be removed according to the angle of each normal line in the process.
(6) Repeating the steps (2) - (5) of the exemption algorithm to finish the face reduction and light weight operation of the BIM model.
The beneficial effects of this embodiment lie in: the method can calculate and distinguish effective and ineffective surface patches from vertex data according to the BIM model original vertex and surface patch data and the light weight level, and automatically remove and decrement the effective and ineffective surface patches from vertex data, so that the ineffective model primitives are removed, the number of geometric elements of the model is reduced, and the method has the advantages of high automation degree, difficulty in error, high processing speed and the like.
Claims (2)
1. The BIM model face reduction method based on vertex normal angle calculation is characterized by comprising the following steps of:
(1) Analyzing and extracting data of the BIM model to obtain geometric basic data of the BIM model, wherein the geometric basic data comprise a vertex array and a triangular patch index array of the BIM model;
(2) Determining a corresponding triangular patch according to the vertex of the BIM model and the triangular patch index, and calculating the normal v of the triangular patch n The calculation method is as follows:
wherein:
v 1 a vector, x, representing one of the edges of the triangular patch 1 、y 1 、z 1 Is vector v 1 Components of (2);
v 2 a vector, x, representing the other edge of the triangular patch 2 、y 2 、z 2 Is vector v 2 Components of (2);
(3) Normal v n Vertex vertexes on the triangular surface patch corresponding to the vertex vertexes m Mapping to obtain the following mapping relation and storing:
wherein: m is 1,2,3, … n;
traversing each vertex on the BIM model m Calculated in vertex m The included angle theta between the triangular patches of the vertex is the included angle set P:
P＝{θ|θ＝degree(v i ，v j )，v i ∈f -1 (vertex m )，v j ∈f -1 (vertex m )}；
wherein: v i 、v j Is vertex m Normal vector of the triangular patch;
(4) Calculating an included angle threshold epsilon of the triangular patches according to the light weight degree requirement of the BIM model, and screening all included angle sets P' smaller than the included angle threshold epsilon from the included angle sets P:
P′＝{θ′|θ′＜ε}；
(5) Deleting data of triangular patches in the included angle set P', and generating a new vertex array and a triangular patch index array;
(6) Repeating the steps (2) - (5) to finish the face reduction operation of the BIM model.
2. The method of face subtraction using BIM model based on vertex normal angle calculation as claimed in claim 1, wherein in step (5), the repeated vertex arrays in the included angle set P' are regenerated into corresponding triangular face index arrays, and each triangular face is based on each triangular faceNormal v of (2) n The index of the vertex is deduplicated.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108595858A (en) * | 2018-04-28 | 2018-09-28 | 成都希盟科技有限公司 | Lightweight advanced treating working method based on BIM |
| CN110414148A (en) * | 2019-07-30 | 2019-11-05 | 中北大学 | Cross-platform online visualization method of open BIM based on WebGL |
| CN110675508A (en) * | 2019-09-10 | 2020-01-10 | 长江勘测规划设计研究有限责任公司 | A BIM model geometry simplification method |
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| CN108595858A (en) * | 2018-04-28 | 2018-09-28 | 成都希盟科技有限公司 | Lightweight advanced treating working method based on BIM |
| CN110414148A (en) * | 2019-07-30 | 2019-11-05 | 中北大学 | Cross-platform online visualization method of open BIM based on WebGL |
| CN110675508A (en) * | 2019-09-10 | 2020-01-10 | 长江勘测规划设计研究有限责任公司 | A BIM model geometry simplification method |
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| Title |
|---|
| glTF在BIM模型轻量化中的应用;吕婧;金浩然;谭军;王鹏;;科技创新与应用;20200225(第06期);全文 * |
| 三维模型面片链码表示方法;魏巍;刘勇奎;段晓东;郭晨;;计算机辅助设计与图形学学报;20170315(第03期);全文 * |
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