Virtual Plant Modeling Based on Mutual Feedback of Function-structure

[Objective] To study virtual plant modeling based on mutual feedback of function-structure.[Method] With the analysis of the shortcomings of current virtual plant modeling method,the modeling with the idea of function-structure mutual feedback was put forward,and the steps of this modeling were elaborated,including the determination of morphological structure model,biomass production model,biomass allocation model,organ reconstruction model,and the integration method of function model and morphological structure model.[Results] The breakthrough of function-structure mutual feedback based mechanism from the boundaries of physiological ecology model and morphological structure model can solve the difficulty of data transmission between the two models and build an integrated model from the two,which can effectively reflect the incidence relation between plant morphology and function,and more suitable for the growth mechanisms of plants.This modeling approach has significant advantages in the dynamic simulation of plant growth.[Conclusion] The virtual plant modeling based on function-structure mutual feedback provides basis for the simulation of plant growth status in the next stage,and has important significance for the accurate simulation of the dynamic growth process of plant.

Approach to Modeling and Virtual-reality-based Simulation for Plant Canopy Lighting

Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ecol- ogy and remote sensing. As many biological processes are driven by light, it is the key for virtual plant to estimate the light absorbed by each organ. This paper presents the radiance equation suitable for calculating sun and sky light intercepted by plant organs based on the principles of the interaction between light and plant canopy firstly; analyzes the process principles of plant canopy primary lighting based on ray casting and projection secondly; describes the multiple scattering of plant lighting based on Monte Carlo ray tracing method and on the radiosity method thirdly; and confirms the research with 3D visualization based on Virtual Reality Modeling Language (VRML) finally. The research is the primary work of digital agriculture, and important for monitoring and estimating corn growth in Northeast China.

WEB-BASED VIRTUAL CNC MACHINE MODELING AND OPERATION

A CNC simulation system based on intemet for operation training of manufacturing facility and manufacturing process simulation is proposed. Firstly, the system framework and a rapid modeling method of CNC machine tool are studied under the virtual environment based on PolyTrans and CAD software. Then, a new method is proposed to enhance and expand the interactive ability of virtual reality modeling language（VRML） by attaining communication among VRML, JavaApplet, JavaScript and Html so as to realize the virtual operation for CNC machine tool. Moreover, the algorithm of material removed simulation based on VRML Z-map is presented. The advantages of this algorithm include less memory requirement and much higher computation. Lastly, the CNC milling machine is taken as an illustrative example for the prototype development in order to validate the feasibility of the proposed approach.

A physics-based approach to motion capture data processing for virtual plant modeling and simulation

Dynamic virtual plant simulation is an attractive research issue in both botany and computer graphics.Data-driven method is an efficient way for motion analysis and animation synthesis.As a widely used tool,motion capture has been used in plant motion data acquisition and analysis.The most prominent and important problem in motion capture for plants is primary data processing such as missing markers reconstruction.This paper presents a novel physics-based approach to motion capture data processing of plants.Firstly,a physics-based mechanics model is found by Lagrangian mechanics for a motion captured plant organ such as a leaf,and then its dynamic mechanical properties are analyzed and relevant model parameters are evaluated.Further,by using the physical model with evaluated parameters,we can calculate the next positions of a maker to reconstruct the missing makers in motion capture sequence.We take an example of a maize leaf and pachira leaf to examine the proposed approach,and the results show that the physics-based method is feasible and effective for plant motion data processing.

Science Letters:Dynamic concision for three-dimensional reconstruction of human organ built with virtual reality modelling language (VRML)

This research studies the process of 3D reconstruction and dynamic concision based on 2D medical digital images using virtual reality modelling language (VRML) and JavaScript language, with a focus on how to realize the dynamic concision of 3D medical model with script node and sensor node in VRML. The 3D reconstruction and concision of body internal organs can be built with such high quality that they are better than those obtained from the traditional methods. With the function of dynamic concision, the VRML browser can offer better windows for man-computer interaction in real-time environment than ever before. 3D reconstruction and dynamic concision with VRML can be used to meet the requirement for the medical observation of 3D reconstruction and have a promising prospect in the fields of medical imaging.

基于VRML的虚拟环境生成工具的研究

虚拟现实建模语言ＶＲＭＬ可应用Ｉｎｔｅｒｎｅｔ网上构造第二代ＷＷＷ。但由于自身的繁杂性，直接构造三维虚拟空间较为困难，若能设计ＶＲＭＬ生成工具，这就大大提高工作效率。本文主要讨论创建ＶＲＭＬ生成工具的基本方法，最后我们利用生成工具完成一个应用实例。

基于VRML的虚拟校园中的三维景观建模

以建筑物和树为例 ,介绍了在基于VRML的虚拟校园建立过程中所涉及到的三维景观建模技术。

基于VRML和VRMLScript的虚拟现实仿真研究

提出了一种使用VRMLScript构建仿真器直接驱动VRML场景的新机制,较好地解决了以往仿真控制中存在的场景抖动、易产生仿真逻辑错误的问题。给出了利用基本三维实体实现场景仿真建模的新方法,使得场景更易于控制和修改,开发了基于VRML的飞机部件装配虚拟现实仿真系统,验证了机制的有效性。

VRML模型创建工具中可视化交互操作的设计和实现

虚拟现实模型语言VRML可用于构建基于Web的虚拟现实,由于直接用传统的文本编辑加浏览器验证的构建方法,未能提供所见即所得的建模手段和可视化的交互操作模式,不便于VRML虚拟场景的创建。鉴于此,在研究VRML现有规范的基础上,用VisualC++6.0作为系统开发平台,用目前通用的3D图形API标准OpenGL实现模型的真实感显示和动态预览,建立了一个VRML模型创建工具,并提供了可视化的交互操作模式,使得用户无须直接接触VRML代码,即可建立基于Web的虚拟场景。

基于VRML的可视化工具的研究

随着网络技术和硬件设施的飞速发展,虚拟现实建模语言(VRML)被广泛用于在因特网上构建虚拟境界。由于VRML语言自身的特点,虚拟现实的制作十分繁琐。如何使用辅助工具来提高开发的效率,具有很重要的意义。本文分析和讨论了几种基于VRML的可视化工具。

基于VRML的虚拟秦汉博物馆的研究与实现

为了保护现有的秦汉文化遗产和提高人们参观博物馆的便捷程度,提出了通过构建虚拟秦汉博物馆网站来达到这双重目的的方法。对开发过程中使用到的物体几何建模、用户交互行为、场景导航图等关键技术进行了研究。重点分析了VRML中虚拟场景交互实现所采用的非编程和编程两种实现方法,并给出了两种交互方案的详细案例。提出了一套适用于VRML虚拟博物馆的虚拟场景优化方案,该方案在保证用户流畅漫游本系统的同时有效地解决了博物馆展品的细节显示问题。最后在网上建立起一个功能比较完善的虚拟秦汉博物馆。

VRML技术在工程类远程教育中的应用

该文集中阐述了利用VRML技术开发远程教育网络课程的优势,讨论了它们的最佳结合方式,并给出了一个具体制作VRML文件的方法。

基于X-VRML的虚拟现实场景建模的研究

基于VRML/X3D的虚拟现实场景建模不能灵活地修改场景的各种内容,缺乏可定制性、可重用性和可扩展性。文章在分析了X-VRML的特点和语法的基础上,研究了基于X-VRML的建模方法,并设计了基于X-VRML的场景模型的浏览结构。

基于VRML与Java3D的交互式虚拟物流系统

为实现虚拟物流系统的实时交互,研究Java3D与VRML的结合方法。通过3D软件建立物流设备图,由VrmlPad导入文件并进行优化,再由Loader接口将VRML造型文件导入到Java3D场景中。借助数据库和Java语言的事件处理器模型以及Java3D的Behavior类,实现人机交互、虚拟漫游以及虚拟场景动西与库存的双向驱动。通过虚拟物流系统实例验证了该方案的有效性。

基于VRML-Java的虚拟装配系统开发

在讨论虚拟装配技术内涵的基础上,提出基于VRML-Java的虚拟装配系统体系结构,该系统实现了装配模型与显示模型的分离,以及系统的平台无关性。分析了虚拟装配环境的构建方法,论述了产品装/拆运动的表示及变换、虚拟装配过程控制策略、虚拟装配中的碰撞检测方法,以及Java与VRML的通信等系统实施的关键技术。开发了虚拟装配仿真软件,以球阀为例进行了验证。

虚拟作物生长VRML实现方法

讨论了基于VRML的虚拟作物的三维建模技术和动态生长显示技术 .

基于VRML的金属材料与热处理虚拟实验系统

研究开发了基于VRML的金属材料与热处理虚拟实验系统 ,在软件内容上以金属材料与热处理的相关典型实验为主 ,既适用于高等院校的实验教学和科研 ,也可为工程技术人员提供功能强大的技术参考和支持。在系统设计上采用B/S结构的网络模式 ,运用数据库、虚拟现实和多媒体技术实现了模拟实验的功能 ,具有交互性好、实验沉浸感强的特点。该实验系统涵盖内容广泛 ,适用性好 ,经过试用取得了较好的效果。

基于SolidWorks-VRML实现虚拟现实的精确建模

研究了在SolidWorks基础上,通过虚拟现实建模语言(VRML)实现虚拟现实精确建模的方法。由于虚拟设备建模精确,可大大节省虚拟现实系统开发中建模的工作量。在以设备为主要仿真对象的虚拟现实系统中,可以优先考虑此种建模方法。最后给出了虚拟工业机器人的精确模型实例。

基于VRML的虚拟模型的构建和交互

介绍了VRML建模的常规方法,比较了现行建模方法的特点,总结了基于语义的描述建模方法,详述了模型开发过程中的建模、转换、装饰、动画和交互等关键技术,最后通过实例展示了运动车床的虚拟模型。

基于VRML的动物解剖虚拟实验的交互设计

动物解剖学教学过程中,由于教学条件不足和标本有刺鼻气味等问题,影响了教学的效果,采用虚拟现实技术对动物解剖学中所需的标本和实验过程进行仿真,可以很好地解决这些问题,因此开发了基于VRML的动物解剖虚拟实验系统。文中对VRML的技术特征进行了介绍。交互设计是虚拟实验构建中的一个重要环节,文中详细阐述了动物解剖虚拟实验中的简单交互设计和扩展交互设计。将该虚拟实验系统用于实际教学中可达到预期的教学效果。