Three-dimensional model boundary line extraction method based on VRML technique

Abstract

The invention provides a three-dimensional model boundary line extraction method based on a VRML technique. The boundary line extraction method includes the following steps of (1) reading a VRML file, recognizing text data through a regular expression and then storing the data in an array in a certain form, (2) setting a normal vector mutation threshold value T which is called a threshold value T for short by a user, wherein the value depends on the largest curvature value on a three-dimensional model, and the larger the curvature value is, the larger the threshold value is, (3) subtracting normal vectors in a unit normal vector array two by two to obtain a vector module, comparing the vector module with the threshold value T, and deleting diagonal lines and repeated boundary lines according to a comparison result, (4) arranging a remaining line segment to obtain a boundary line array, writing the boundary line array and a coordinate array into a data form document, and storing the data form document in a disk of a computer. The method is wide in application range and can be used for processing any three-dimensional model with complicated appearance.

Description

technical field [0001] The invention relates to the field of computer graphics, and relates to a method for extracting boundary lines of three-dimensional models based on VRML technology. Background technique [0002] At present, the research on the boundary line extraction of 3D models mainly includes the following two aspects: (1) From the perspective of the two-dimensional image, some image processing methods are used to extract the boundary line, and the extraction result is another picture. Obviously, this method cannot contain The analytical formula of each boundary line in three dimensions; (2) Starting from the real object, the point cloud is obtained by scanning or measuring, and then the points belonging to the boundary line are obtained through a search algorithm, and finally the reverse modeling is performed on the computer. The second method can obtain the analytical expression of the boundary line in 3D, can handle dense point cloud data, and is generally used ...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that the model boundary line data cannot be obtained directly from the 3D modeling software, the present invention starts from the 3D model and provides a method for extracting the boundary line of the 3D model based on VRML technology. This method has a wide range of applications and can handle arbitrary complex shapes. 3D model of appearance

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