中文摘要：

针对秋天树叶形变过程的仿真问题,在双层质点-弹簧模型的基础上,提出一种半过程半物理的树叶形变快速仿真算法.由于同时调节叶肉和叶脉弹簧系数会使得树叶形变不易控制,因此对叶脉和叶肉分开进行模拟：为叶脉设计一种目标形态,叶脉形变序列的中间形态可以通过对初态和终态的插值得到,叶肉会在叶脉形变引发的弹簧力的牵引下发生相应的形变,质点-弹簧系统会在阻尼的作用下趋于稳定,上述过程是一个不断循环迭代的过程;针对显式积分求解器求解时间过长和不稳定的缺点,采用大时间步长的隐式积分求解器以显著地提高系统的稳定性和求解效率.算法分析和实验结果表明,该算法可以稳定、快速、逼真地模拟秋天树叶老化过程中几何形态的变化过程.

英文摘要：

The paper proposes a fast leaves deformation simulation algorithm, which is built on the Double-Layered Model（DLM）. Adjusting venations and mesophylls＇ coefficients together makes the deformation difficult to control. In our system, mesophylls and venations are simulated separately. First, we set a target state for the venations, and the intermediate states of the venations will be achieved by interpolating between the initial state and the target state. Then the mesophylls will be driven to the proper positions by the spring forces caused by the venations＇ deformation. The stability of the mass-spring system is guaranteed by the damping forces. The original DLM is both numerical instable and time-consuming, so implicit integration is adopted for our mass-spring system. The experimental results show that the proposed techniques could efficiently simulate the deformation process of senescent leaves realistically.