虚拟树木生长建模及可视化研究综述

虚拟树木,就是应用计算机模拟树木在三维空间中的生长发育状况,近年来已成为植物学、农林业、环境科学和计算机领域的研究热点.生长模型和可视化技术是它的核心内容.虚拟树木生长模型包括形态结构模型、功能模型和结构-功能模型等,其中结构-功能模型可以模拟树木与环境间的相互关系,其结果为树木的三维结构,因此它最为接近现实树木的生长,是虚拟树木生长模型的发展方向.树木形态的复杂性与计算时间和空间的矛盾一直是可视化研究中的难点.树木可视化还有不同于其他物体的特性,如多级分枝、枝条的弯曲、自相似、向光性、树木分枝间的光滑与非光滑连接等.树木可视化软件可分为2类:纯图形学软件和基于结构-功能模型的软件,其应用已涉及娱乐、商业、计算机辅助景观设计、教育、科研和林业生产等方面;但在树木构筑型数据的采集和管理、结构-功能模型的建立、树木可视化技术的研究及面向林业生产等方面仍需要大量的工作.

A Review on Growth Modelling and Visualization for Virtual Trees

Virtual trees are models that describe the growth and development of a tree in 3D space by computer simulation.The study of virtual plants has been more and more popular in botany,agriculture,forestry,environmental sciences and computer.Growth modelling and visualization techniques are essential parts of virtual plants.Growth models of virtual trees include morphological structural models,functional models and functional-structural models.Functional-structural models may simulate the interaction between trees and its environment,whose outputs are 3D structure of trees.Therefore,functional-structural models are more close to realistic tree growth process and lead the trend of tree growth modelling.One of the major difficulties in tree visualization is the contradiction of between computer time and memory occupation and tree morphological structure complexity.Specific features different from normal objects for visualization cover self-similarity,ramification,branch bending,phototaxy,smoothly and un-smoothly blending branching etc.Tree visualization software is based on either pure graphics or functional-structural models,which has been applied in games,commerce,computer-assistant landscape design and forestry education,research and practice.Further work should be done in the collection and management of tree architecture data,the development of functional-structural models,the visualization techniques and forestry-oriented application.