Method for detecting self collision of flexible fabric based on quad bounding box tree

Abstract

The invention relates to a method for detecting self collision of a flexible fabric based on a quad bounding box tree. The method is characterized in that: the quad bounding box tree is built for fabric geometric primitives; triangle facets which are impossible to intersect in a coarse detection stage and a precise intersection stage are filtered by a normal vector cone method, a triangle facet gravity center detecting method and a planar ipsilateral filtering method based on the quad bounding box tree respectively so as to greatly reduce the computation of intersection tests. The method comprises the following steps: (1) building the quad bounding box tree with a compact structure by using a space position relation of the fabric geometric primitives; (2) excluding triangle facet pairs impossible to intersect based on the quad bounding box tree by the normal vector cone method; (3) filtering the triangle facets of which the distance is larger than a preset threshold value according to the distance between the gravity centers of two triangle facets; and (4) filtering the unnecessary line planar intersection by the precise detection among basic geometrical elements and the planar ipsilateral filtering method.

Description

technical field [0001] The invention relates to a flexible fabric self-collision detection method based on a quadrilateral bounding box tree, and belongs to the technical field of flexible fabric simulation collision detection. Background technique [0002] Collision processing includes two parts: collision detection and collision response. The goal of collision detection is to find and report collisions; collision response is to make the collided objects take correct actions according to the collision point and other parameters after the collision occurs, so as to reflect the real dynamic effect. [0003] The existing space-based collision detection algorithms can be roughly divided into two categories: space decomposition method (Space Decomposition) and hierarchical bounding box method (Hierarchical Bounding Volumes). The main idea of ​​these two types of algorithms is to reduce the number of measured elements to improve algorithm efficiency. [0004] The space decompos...

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Problems solved by technology

[0010] (1) Establish a hierarchical bounding box tree in the form of a binary tree, and the leaf node contains only one primitive. Although this method is easy to understand and implement, when the number of leaf nodes is large, the height of the tree will increase rapidly. On the one hand, this makes the memory usage large, on the other hand, it reduces the efficiency of the algorithm.

[0011] (2) The traditional method does not consider the spatial position relationship of geometric primitives in the process of building the bounding box tree from the bottom up, which will lead to a loose hierarchical bounding box structure to a certain extent, thus affecting the efficiency of collision detection

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