Improved method for calculating vertex normal of curved surface grid in grid division

Abstract

An improved method for curved surface grid vertex normal calculation in grid division comprises the steps: S1, judging whether the vertex of a given curved surface is a singular point or not: if yes,executing the step S2, and otherwise, executing the step S3; S2, based on the geometric parameters of the given curved surface, calculating the normal direction of the singular point, and entering S7;S3, solving a tangent vector in the UV direction at the vertex, judging whether the tangent vector is zero or not: if so, entering S4, and otherwise, entering S5; S4, calculating the normal directionof the vertex, judging whether the normal direction is a non-zero vector or not: if yes, entering S7, and otherwise, entering S6; S5, obtaining the normal direction through cross multiplication of the two tangent vectors, executing the step S7; S6, averaging the normal lines of all the triangular patches connected to the vertex to serve as a vertex normal line direction, and entering S7; S7, outputting a normal direction; S8, when a point set is generated based on the boundary of the triangular patch model, interpolating to generate the point set on the boundary according to the normal direction, and performing triangular mesh generation on a given curved surface.

Description

technical field [0001] The invention relates to an improved method for calculating the vertex normals of curved surface grids in grid division, which can be applied to the field of computer graphics, and particularly relates to the vertex normals of subdivided triangular facets contained in curved surface graphics. Background technique [0002] The normal direction of a point on a surface refers to the direction perpendicular to the surface at that point. For a plane, the normal direction of each point on the plane is the same. For a curved surface, the normal direction of each point is the same. Not the same. As an important attribute of the surface, the normal direction is widely used in the field of graphics, and its correctness has a direct impact on the lighting, shadow effects, texture effects, etc. in the graphics scene. Applying the normal information of the surface to the meshing process of CAE software can improve the quality of meshing. Usually, there are two wa...

AI Technical Summary

Problems solved by technology

[0009] Aiming at the problems and deficiencies in the prior art, the present invention provides an improved method for calculating the vertex normal of a surface mesh in mesh division, and solves the problem that the existing method is not widely applicable

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