A Virtual Cutting Method of Tetrahedral Mesh Based on Path Separation

Abstract

A tetrahedral mesh virtual cutting method based on route separation comprises the steps that 1, data of a tetrahedral mesh is read, and a surface triangular patch set of the tetrahedral mesh is obtained; 2, a collision detecting thread is started, and a thread from the surface triangular patch set to a screen is displayed; 3, after collision detection occurs, track discretization of a tool is started, feature point processing is carried out, and meanwhile selection of an optimal route is started; 4, a tetrahedron shared by two first points on the optimal route is separated; 5, the two points in the step 4 are deleted. In the cutting process, each colliding patch is evaluated through an evaluation function, the optimal point is selected to serve as a route of a cutting track, and then tetrahedron separation is carried out; due to the fact that only topological separation exists in the cutting process, and no pathological tetrahedrons are generated, the stability of finite element computing is improved, the number of the tetrahedrons is not increased, and the computing speed is kept.

Description

technical field [0001] The invention belongs to the technical field of computer science, and more specifically relates to a method for virtual cutting of tetrahedron grids based on path separation. Background technique [0002] The cutting of soft tissue is an important part of virtual surgery in the medical field. It not only needs to meet the fidelity, but also must follow the physical characteristics and real-time changes of biological tissues, which is a very challenging subject. [0003] At present, the soft tissue models at home and abroad are more representative of the mass-spring model and the finite element model. The mass point-spring model is simple and quick to calculate, and only needs to update the topology when cutting or resetting the mesh, which can easily simulate the cutting of objects, but its simple model determines that the accuracy of deformation cannot be guaranteed during the operation. The finite element model can accurately simulate the deformatio...

AI Technical Summary

Problems solved by technology

The mass point-spring model is simple and fast to calculate, and only needs to update the topology when cutting or resetting the mesh, which can easily simulate the cutting of objects, but its simple model determines that the accuracy of deformation cannot be guaranteed during the operation

The finite element model can accurately simulate the deformation with physical meaning, but the quantity and quality of the tetrahedral mesh will have a direct impact on the computational stability of the finite element

The speed and quality of cutting have a great impact on virtual surgery. The main task of cutting is to meet the change of model topology under cutting conditions. The simplest cutting method is the removal method. Although the calculation amount is small and the implementation is simple, However, the law of conservation of mass is violated, and the cutting boundary is jagged and aliased

The vertex copy needs to be accurately recorded and will produce irregular shapes due to the copied position, which will lead to subsequent reprocessing, making the steps complicated, easy to generate small meshes, and affecting finite element calculations

Similarly, the cutting method of subdividing tetrahedral grids is also prone to irregular grids. In order to eliminate irregular grids, it is necessary to split multiple times on a tetrahedral grid to generate multiple sub-tetrahedrons. Under continuous cutting, It is easy to slow down the finite element calculation, and due to the existence of small tetrahedron, it will lead to the instability of finite element calculation

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