国家自然科学基金(60833007, 60773030, 60973066); 国家高技术研究发展计划(863)(2008AA01Z301); 澳门大学研究基金
提出了一种应用物理学原理的树枝和雨滴交互作用的真实感动态仿真技术.树枝和叶柄被描述为一种方便由4 种弹簧控制的三棱柱弹簧模型(extended three-prism spring model,简称ETPSM).树枝、树叶的运动源于树枝系统与雨滴相互之间能量的双向转换.二者之间的交互作用可以通过一种高效的技术很好地模拟.该技术被专门设计用来模拟液体在具有亲水性的非刚体表面上运动.当雨滴撞击树枝后,树枝会发生震动与转动;雨滴会沿着树叶表面流动,合并成一个更大的雨滴或者悬挂在叶片边缘;当雨滴从树叶边缘落下后,树枝会弹起并恢复到原来的位置.实验结果表明,该技术能够高效、真实地仿真雨滴撞击树枝系统后的相互作用效果,同时可以简单而有效地模拟杆状物体在外力作用下的弹性形变,诸如旋转、震动等.
This paper presents an approach to animate realistic interactions between tree branches and raindrops, based on physical theory. Tree branches and petioles are represented by a model namely ETPSM (extended three-prism spring model) with three-prism structures, which can be flexibly controlled by four kinds of spring systems. The branches and leaves are animated due to the bidirectional transference of kinetic energy between raindrops and the branch system. The interactions between them can be well simulated by an efficient technique, specially designed for liquid motion on non-rigid objects with hydrophilic surfaces. When the branches are impacted by a raindrop, they will vibrate and twist, and the raindrops will flow along the leaf vein, merge into larger ones, or hang on the leaf apex, and the branch will rebound and vibrate for a while after the raindrop falls off the leaf, finally into a rest place. Experimental results show that this approach can be used to efficiently and realistically simulate these interactions between tree branches and raindrops; meanwhile, it can efficiently and easily simulate the elastic deformation of rod under the influence of external forces, such as rotation and vibration.