虚拟森林环境中树木风致响应及其损伤的三维动态建模与仿真

项目名称： 虚拟森林环境中树木风致响应及其损伤的三维动态建模与仿真

项目编号： No.31200430

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 林学

项目作者： 林定

作者单位： 福州大学

项目金额： 22万元

中文摘要： 风是影响森林内部微环境和可在短时间内造成森林群落机械损伤的复杂自然因素之一。本项目以南方主要树种-杉木为例，以风-树之间复杂交互行为为研究主线，深入分析风-树之间交互作用的定量关系，探索树木风致振动以及机械损伤的机理模型。提取显著影响树木风致动力学响应特性的各种主要参数（树冠结构参数、材质力学参数等）用于指导虚拟树木动态建模，利用这些参数建立简化条件下基于悬臂梁的虚拟树木动态模拟物理模型。结合物理和几何模型，应用虚拟树木交互式修剪、粒子系统、动态纹理合成等模拟不同树冠特征的杉木在不同强度风荷载下的动态响应（摇曳/凋落/折断）。在场景相似性分析的基础上，综合利用多级实例化、凋落路径复用、物理变形复用、LOD、GPU等技术构建一个与风要素动态交互的虚拟森林环境，使人们能够在可视化环境下更有效地观察、理解与解释树木与风的交互作用过程及其生物力学性能特征，提高森林资源保护和应对森林风害的能力。

中文关键词： 风-树交互；风致振动；建模与仿真；落叶；虚拟植物

英文摘要： Wind is one of the complex natural factors which can affect forest internal microenvironment and may cause mechanical damage to forest community in a short time. Taking fir, a main species in south China as an example and the complex tree-wind interaction as the main subject, this research investigates in depth the quantitative relationship during the process of wind-trees interactions, then explores the principles of tree's wind-induced vibration and mechanical damage. All kinds of major parameters (canopy structural parameters, material mechanics parameters, etc.) that significantly influence tree's wind-induced dynamic response characteristics are extracted and used to guide the dynamic tree modeling process. These parameters are also used to create cantilever beam based physical dynamic tree simulation model under simplified conditions. We employ a number of techniques such as interactive virtual tree pruning, particle system, dynamic texture synthesis, etc., to simulate the dynamic process of Chinese fir with different crown characteristics in response to different wind loads (such as swaying, falling, fracturing). Based on the self-similarity analysis of scene, we integrate multi-level instancing, falling path reusing, physical deformation reusing, LOD, GPU techniques to construct a virtual forest environ

英文关键词： Wind-tree Interaction；wind-induced vibration；modeling & simulation；defoliation；virtual plant