作物可视化中的碰撞检测及响应研究

Collision Detection and Response in Crop Visualization

将碰撞检测与响应技术引入作物可视化生长模拟,针对以NURBS曲面表示的作物叶片,提出了一种基于曲面分割技术及混合层次包围盒实现作物叶片间碰撞检测的方法。首先采用节点插入技术分割叶片曲面,然后为分割后的叶片曲面建立轴向包围盒(AABB)与固定方向凸包(FDH)的混合层次包围盒树:根节点采用AABB包围盒,以快速排除不可能相交的叶片;其它层节点采用FDH包围盒,以保证精确地判定距离较近的叶片间碰撞状态。在此基础上,根据作物叶片形态变化规律,提出了较合理、有效的冲突响应机制。实例分析表明,所建立的算法可有效地应用于作物叶片碰撞的模拟实现。

Adopting the collision detection and response methodology into the field of crop growth visualization,an algorithm used for collision detection between leaves defined by NURBS（Non Uniform Rational B-Spline）surfaces was proposed based on the techniques of surface subdivision and hybrid hierarchical bounding volume（HHBV）.Firstly,the leaf surface was subdivided by using the technique of inserting node.Secondly,a HHBV tree for the subdivided leaf based on AABB（Axis-Aligned Bounding Box） and FDH（Fixed Direction Hull） was developed.The HHBV tree used AABB as its root node for fast overlap test,and used FDH as other nodes for accurately determine the contact status between leaves in closer proximity.Finally,based on leaf morphological architecture,reasonable and efficient solutions for collision response were presented.Further results proved that the algorithm was efficient for realizing leaves collision simulation.