基于分块策略的虚拟场景建模算法的研究
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摘要
近几年来，随着各种计算机技术的飞速发展，虚拟现实得到了越来越多的应用。Internet网络走进千家万户，更是推动了分布式虚拟现实的发展。分布式虚拟场景的实时显示在虚拟现实中具有重要的地位，也是虚拟现实研究的重点和难点。而虚拟场景的建模和分块策略对场景的实时显示具有很大的影响，因此，虚拟场景的建模和分块策略成为虚拟现实研究的重要内容。本文重点对场景建模和场景分块的一些算法做了研究，并取得以下成果：
首先，对虚拟场景的各种主要建模方法做了研究。虚拟环境的建模是整个虚拟现实系统建立的基础，主要包括几何建模、运动建模、物理建模、对象特征建模等方法，每种方法各有优缺点。本文拟采用几种建模方法相结合的策略，对场景中逼真度要求比较高的对象，侧重于几何建模；场景中运动方式比较多的对象，侧重于运动建模等。这样产生的结果是：不要求在
太原理工大学硕士研究生学位论文
某些方面特性突出，但可弥补采用单一建模方法产生的沉浸感
弱等缺陷。
其次，对现有的场景分块策略作了详细的研究，现有的场
景分块策略是建立在规整的正四边形基础之上的。因此，它的
调度策略是当视点移动时，采用1+8+16策略。在蜂窝式电话服
务网络的启发下，本文对现有的算法做了改进，提出了基于正
六边形的场景分块策略，当视点移动时，与当前可见区相邻的
6块最有可能成为下一个可见区，而外层的12个区是当前可见
区的下一可见区的预可见区。所以在显示当前可见区时，保证
对应的6个预可见区的场景数据信息己经处理完毕并与当前可
见区的场景一起存放在内存中。而这同时并行处理12块将来预
可见区的数据。本文也就称这种策略为卜6+l2策略，即:显示
1块，调入6块，计算12块。优点是:场景显示时，空间复杂
度明显降低了。提高了场景显示的实时性和沉浸感。
再次，场景采用一维数组链表存储。本文提出的X+Y存储
算法，是对现有二维数组存储方式的一种改进。相当于在原来
的基础上加了一级索引。提高了场景块的查找速度，提高了定
位的速率。增强了实时性。
太原理工大学硕士研究生学位论文
最后，本文对单块场景的建模也提出了一点改进。
Recently, with the rapid development of the computer technology, virtual reality has been used in more and more fields, and with the popularization of Internet, the evolution of the distributed virtual reality has been accelerated. As the emphases and the difficulty of the research about the virtual reality, to display the scene of the distributed virtual environment in time plays an important role, and the modeling and partition strategy of the virtual scene can affect the real-time display of the scene largely, so they are main content of the research of the virtual reality, we stress some arithmetics about the modeling and partition strategy, and we get some achievements as follows:
Firstly, the research of main modeling method in virtual scene has been given. Usually, the existing modeling method is based on
the use of the single or some of the modeling methods, such as geometrical modeling, motorial modeling, physical modeling and object character modeling. So the result is: the characteristic of one side for the scene is prominent, but the other side is very poor. In this thesis, we use all these modeling methods, geometrical modeling to objects which need high realistic, motorial modeling to which require more movements. Then the result will be better: no prominent on one side, but the limitation of the method we mentioned is improved.
Secondly, we research the partition strategy to the existing scene in detail which is based on the regular quadrangle. So its attempering strategy is to adopt "1+8+16"strategy when the viewpoint moves. Under the elicitation of honeycomb telephone service net, we ameliorate the existing arithmetic, propose a partition strategy based on regular hexagon. When viewpoint moves, there are six blocks near to the current visible area may be the next one, while the outer 12 blocks may be the pre-visible area of the next visible area. So while displaying the current visible area,
we should make sure that the scene data information of the corresponding 6 pre-visible areas has been operated, and they have been saved into memory together with that of the current visible area. Meanwhile, the data of 12 pre-visible areas been operated parallelly. This strategy can be called "1+6+12" strategy in this thesis. That is: to display 1 block , fold 6 blocks, compute 12 blocks. Its merit is the special complexity has been reduced evidently when the scene displayed , and the real-time ability and immersion has been improved.
Thirdly , the scene is saved in the array linking list in one-dimension, we bring forward X+Y saving-arithmetic which is an improvement for the existing array in two_dimension. That is to say we add the first-refrence on the base of the former , which quickens up the lookup for the scene block , improves the speed of the orientation and boosts up the real-time ability.
Lastly, we put forward a little improving advice for modeling to the single block sence in this thesis.
首先，对虚拟场景的各种主要建模方法做了研究。虚拟环境的建模是整个虚拟现实系统建立的基础，主要包括几何建模、运动建模、物理建模、对象特征建模等方法，每种方法各有优缺点。本文拟采用几种建模方法相结合的策略，对场景中逼真度要求比较高的对象，侧重于几何建模；场景中运动方式比较多的对象，侧重于运动建模等。这样产生的结果是：不要求在
太原理工大学硕士研究生学位论文
某些方面特性突出，但可弥补采用单一建模方法产生的沉浸感
弱等缺陷。
其次，对现有的场景分块策略作了详细的研究，现有的场
景分块策略是建立在规整的正四边形基础之上的。因此，它的
调度策略是当视点移动时，采用1+8+16策略。在蜂窝式电话服
务网络的启发下，本文对现有的算法做了改进，提出了基于正
六边形的场景分块策略，当视点移动时，与当前可见区相邻的
6块最有可能成为下一个可见区，而外层的12个区是当前可见
区的下一可见区的预可见区。所以在显示当前可见区时，保证
对应的6个预可见区的场景数据信息己经处理完毕并与当前可
见区的场景一起存放在内存中。而这同时并行处理12块将来预
可见区的数据。本文也就称这种策略为卜6+l2策略，即:显示
1块，调入6块，计算12块。优点是:场景显示时，空间复杂
度明显降低了。提高了场景显示的实时性和沉浸感。
再次，场景采用一维数组链表存储。本文提出的X+Y存储
算法，是对现有二维数组存储方式的一种改进。相当于在原来
的基础上加了一级索引。提高了场景块的查找速度，提高了定
位的速率。增强了实时性。
太原理工大学硕士研究生学位论文
最后，本文对单块场景的建模也提出了一点改进。
Recently, with the rapid development of the computer technology, virtual reality has been used in more and more fields, and with the popularization of Internet, the evolution of the distributed virtual reality has been accelerated. As the emphases and the difficulty of the research about the virtual reality, to display the scene of the distributed virtual environment in time plays an important role, and the modeling and partition strategy of the virtual scene can affect the real-time display of the scene largely, so they are main content of the research of the virtual reality, we stress some arithmetics about the modeling and partition strategy, and we get some achievements as follows:
Firstly, the research of main modeling method in virtual scene has been given. Usually, the existing modeling method is based on
the use of the single or some of the modeling methods, such as geometrical modeling, motorial modeling, physical modeling and object character modeling. So the result is: the characteristic of one side for the scene is prominent, but the other side is very poor. In this thesis, we use all these modeling methods, geometrical modeling to objects which need high realistic, motorial modeling to which require more movements. Then the result will be better: no prominent on one side, but the limitation of the method we mentioned is improved.
Secondly, we research the partition strategy to the existing scene in detail which is based on the regular quadrangle. So its attempering strategy is to adopt "1+8+16"strategy when the viewpoint moves. Under the elicitation of honeycomb telephone service net, we ameliorate the existing arithmetic, propose a partition strategy based on regular hexagon. When viewpoint moves, there are six blocks near to the current visible area may be the next one, while the outer 12 blocks may be the pre-visible area of the next visible area. So while displaying the current visible area,
we should make sure that the scene data information of the corresponding 6 pre-visible areas has been operated, and they have been saved into memory together with that of the current visible area. Meanwhile, the data of 12 pre-visible areas been operated parallelly. This strategy can be called "1+6+12" strategy in this thesis. That is: to display 1 block , fold 6 blocks, compute 12 blocks. Its merit is the special complexity has been reduced evidently when the scene displayed , and the real-time ability and immersion has been improved.
Thirdly , the scene is saved in the array linking list in one-dimension, we bring forward X+Y saving-arithmetic which is an improvement for the existing array in two_dimension. That is to say we add the first-refrence on the base of the former , which quickens up the lookup for the scene block , improves the speed of the orientation and boosts up the real-time ability.
Lastly, we put forward a little improving advice for modeling to the single block sence in this thesis.
引文
[1]周晓琪。虚拟现实技术。电信科学。1996，12(7)，47-50
[2]曾芬芳，解洪成。虚拟现实技术及其应用。华东船舶工业学院学报。1995，9(1)，80-84
[3]赵沁平．《DVENET分布式虚拟环境》．北京：科学出版社 2002，7-19
[4]黄心渊．《虚拟现实技术与应用》．北京：科学出版社 1999，5-41
[5]杨宝民 朱一宁．《分布式虚拟现实技术及其应用》．北京：科学出版社 2000，4-34
[6]杨孟洲等．分布式虚拟现实系统体系结构．计算机应用研究，2000，7：1．3．
[7]张国宣等．基于VR的多模式多代理人机交互接口．计算机应用研究，2000，10：91-94．
[8]杨孟洲等．多用户分布式虚拟环境系统MUDVE的实现技术．计算机辅助设计与图形学学报，2001，13(2)：173-178．
[9]郑援等．虚拟实体对象的行为建模方法研究．国防科技大学学报，1998，20(1)：78-81．
[14]刘锦德、敬万钧，关于虚拟现实一核心概念与工作定义，计算机应用，1997，03
[10]马小虎 潘志庚 石教英，虚拟现实系统的体系结构和软件开发工具，计算机工程与应用，[16]1997，08
[11]张云勇，白中建，敬万钧，虚拟现实系统的建立，计算机应用，2000，S1
[12]王汝传，陈丹伟，顾翔，虚拟现实技术及其实现研究，计算机工程，2000，12
[13]胡忠东，樊爱华，虚拟现实工具，计算机仿真，1997，03
[14]赵沁平，怀进鹏，李波等，虚拟现实研究概况，计算机研究与发展，1996，7
[15]陈小武，何红梅，段作义，基于多平台的虚拟视景生成计算机研究与发展，1998，12
[16]郑援，李思昆，胡成军，彭宇行，虚拟实体对象建模语言SCPL计算机学报，1999，3
[17]赵沁平，怀进鹏，李波，沈旭昆，虚拟现实研究概况，计算机研究与发展，1996，7
[18]杨键，耿卫东，潘云鹤，李明，基于图像的虚拟景观漫游，计算机辅助设计与图形学学报 2001，3
[19]王兆其，赵沁平，汪成为，虚拟环境中物体物理特性的表示与处理，计算机研究与发展，1998，2
[20]孙立新，诸昌铃，分布式虚拟环境中基于同步控制的预测研究，计算机仿真，2001，5
[21]张哲，杨世兴，徐敦滋，STAGE软件在潜艇作战系统支撑环境中的应用研究，西北工业大学工程硕士学位论文，2001，5
[22]范哲，顾毓清，分布式虚拟环境技术的一些研究，中国科学院软件研究所，硕士论文，2001，5
[23]罗亚波，基于Internet的图像与建模相结合的虚拟现实关键技术研究，武汉理工大学硕士论文，2001，10
[24]刘华峰，金士尧，基于web的分布式虚拟环境预研及原型设计，国防科学技术大学硕士论文，2002，1
[25]Bernard P.Zeigler, Herbert Praehofer, Tag Gon Kim. Theory of Modeling and Simulation. New York, Academic Pr,2000
[26]Roy Chan, Urban Simulation, A Revolutionary Tool for Participatory Planning. Available online at
[27]http://www.multigen.com/support/dc_files/Urban_Sim_White_Paper_participate.doc.2000
[28] http://www.web3d.org
[29] http://www.shout3d.com
[30] Fishwick P. A. Web-Based Simulation. Some Persnal Observations. Proceedings of the 1996 Winter Simulation Conference.772-779,1996.12
[31] Steve Pettifer, Jon Cook,James Marsh and Adrian West,DEVA3: Architecture for a large-scale distributed virtual reality system.
[32] Paul Sharkey, Steve Benford and Kevin Warwick, Large scale real time multi-user Virtual reality CASE FOR SUPPORT.October 4,1995
[33] http://www.cai.com/cosmo
[34] Tulio Sulbaran and Nelson Baker, A Study of Engineering Students Interaction With Distributed Virtual Reality in the Classroom. 2000 ASEE Southeast Section Conference.
[35] Department of Computer Science, The University of Nottingham, Nottingham, NG72RD,UK.MASSIVE: a Distributed Virtual Reality System Incorporating Spatial Trading.
[36] A Mobile Distributed Meeting Service based on Virtual Reality techniques. http://www.cyclovision.com.Feb.99.
[37] Roy Ladner, Larry Klos, Mahdi Abdelguerfi, Golden G.. Richard, A Distributed Virtual Reality Prototype for Real Time GPS Data
[38] J.M. Bishop. Virtual bodies and virtual spaces, http://www.emerald-librarv.com/ft.
[39] J.M.ZHENG, K.W.CHAN AND I.GIBSON. Desktop virtual reality interface for computer aided conceptual design using geometric techniques. J. ENG.DESIGN,2001, VOL. 12, NO.4,309-329.
[40] M.Iqbal,M.S.J.Hashmi. Design and analysis of a virtual factory layout. Journal of Materials Processing Technology 118(2001) 403-410.
[41] Randy S Haluck. Are Surgery Training Programs Ready for Virtual Reality?A
Survey of Program Direction in General Surgery. Haluck et al. Vol.193,No.6,December 2001 660-665.
[42] T.P.Grantcarov. Virtual reality computer simulation. Surgical Endoscopy(2001) 15: 242-244.
[43] By N. Okan, Metropolitan State University. Virtual Reality. Futurics Vol.25, No.3 & 4, 2001.
[44] M.Iqbal,M.S.J.Hashmi. Design and analysis of a virtual factory layout. Journal of Materials Processing Technology 118(2001) 403-410.
[45] T.P.Grantcarov. Virtual reality computer simulation. Surgical Endoscopy(2001) 15: 242-244.
[46] By N.Okan, Metropolitan State University. Virtual Reality. Futurics Vol.25,No.3 & 4, 2001.
[47] A Mobile Distributed Meeting Service based on Virtual Reality techniques. http://www.cyclovision.com.Feb.99.
[48] Roy Ladner, Larry Klos, Mahdi Abdelguerfi, Golden G.. Richard, A Distributed Virtual Reality Prototype for Real Time GPS Data
[49] 周廷美等．虚拟汽车风洞．系统仿真学报，2002，14(1)：107-109
[50] 娄渊胜，朱跃龙等．基于虚拟现实技术的实事漫游系统研究及实现．计算机工程，2001，27(6)：98-99．
[51] Department of Computer Science, The University of Nottingham, Nottingham, NG72RD, UK. MASSIVE: a Distributed Virtual Reality System Incorporating Spatial Trading.
[52] 赵沁平，沈旭昆，夏春和．DVENET：一个分布式虚拟环境．计算机研究与发展，1998，35(12)：1065-1068
[53] Randy S Haluck. Are Surgery Training Programs Ready for Virtual Reality? A Survey of Program Direction in General Surgery. Haluck et al. Vol. 193, No.6,December 2001 660-665.
[54] 何红梅，王兆其，陈小武．DVENET应用程序框架的设计与实现．计算机研究与发展，2000，36(12)：1070-1072
[55] 陈谊，赵敏哲，梁炳成。分布式虚拟现实及其在仿真中的应用。计算机仿真，2002，1月。文章编号：1006-9348(2002)01-0009-05
[2]曾芬芳，解洪成。虚拟现实技术及其应用。华东船舶工业学院学报。1995，9(1)，80-84
[3]赵沁平．《DVENET分布式虚拟环境》．北京：科学出版社 2002，7-19
[4]黄心渊．《虚拟现实技术与应用》．北京：科学出版社 1999，5-41
[5]杨宝民 朱一宁．《分布式虚拟现实技术及其应用》．北京：科学出版社 2000，4-34
[6]杨孟洲等．分布式虚拟现实系统体系结构．计算机应用研究，2000，7：1．3．
[7]张国宣等．基于VR的多模式多代理人机交互接口．计算机应用研究，2000，10：91-94．
[8]杨孟洲等．多用户分布式虚拟环境系统MUDVE的实现技术．计算机辅助设计与图形学学报，2001，13(2)：173-178．
[9]郑援等．虚拟实体对象的行为建模方法研究．国防科技大学学报，1998，20(1)：78-81．
[14]刘锦德、敬万钧，关于虚拟现实一核心概念与工作定义，计算机应用，1997，03
[10]马小虎 潘志庚 石教英，虚拟现实系统的体系结构和软件开发工具，计算机工程与应用，[16]1997，08
[11]张云勇，白中建，敬万钧，虚拟现实系统的建立，计算机应用，2000，S1
[12]王汝传，陈丹伟，顾翔，虚拟现实技术及其实现研究，计算机工程，2000，12
[13]胡忠东，樊爱华，虚拟现实工具，计算机仿真，1997，03
[14]赵沁平，怀进鹏，李波等，虚拟现实研究概况，计算机研究与发展，1996，7
[15]陈小武，何红梅，段作义，基于多平台的虚拟视景生成计算机研究与发展，1998，12
[16]郑援，李思昆，胡成军，彭宇行，虚拟实体对象建模语言SCPL计算机学报，1999，3
[17]赵沁平，怀进鹏，李波，沈旭昆，虚拟现实研究概况，计算机研究与发展，1996，7
[18]杨键，耿卫东，潘云鹤，李明，基于图像的虚拟景观漫游，计算机辅助设计与图形学学报 2001，3
[19]王兆其，赵沁平，汪成为，虚拟环境中物体物理特性的表示与处理，计算机研究与发展，1998，2
[20]孙立新，诸昌铃，分布式虚拟环境中基于同步控制的预测研究，计算机仿真，2001，5
[21]张哲，杨世兴，徐敦滋，STAGE软件在潜艇作战系统支撑环境中的应用研究，西北工业大学工程硕士学位论文，2001，5
[22]范哲，顾毓清，分布式虚拟环境技术的一些研究，中国科学院软件研究所，硕士论文，2001，5
[23]罗亚波，基于Internet的图像与建模相结合的虚拟现实关键技术研究，武汉理工大学硕士论文，2001，10
[24]刘华峰，金士尧，基于web的分布式虚拟环境预研及原型设计，国防科学技术大学硕士论文，2002，1
[25]Bernard P.Zeigler, Herbert Praehofer, Tag Gon Kim. Theory of Modeling and Simulation. New York, Academic Pr,2000
[26]Roy Chan, Urban Simulation, A Revolutionary Tool for Participatory Planning. Available online at
[27]http://www.multigen.com/support/dc_files/Urban_Sim_White_Paper_participate.doc.2000
[28] http://www.web3d.org
[29] http://www.shout3d.com
[30] Fishwick P. A. Web-Based Simulation. Some Persnal Observations. Proceedings of the 1996 Winter Simulation Conference.772-779,1996.12
[31] Steve Pettifer, Jon Cook,James Marsh and Adrian West,DEVA3: Architecture for a large-scale distributed virtual reality system.
[32] Paul Sharkey, Steve Benford and Kevin Warwick, Large scale real time multi-user Virtual reality CASE FOR SUPPORT.October 4,1995
[33] http://www.cai.com/cosmo
[34] Tulio Sulbaran and Nelson Baker, A Study of Engineering Students Interaction With Distributed Virtual Reality in the Classroom. 2000 ASEE Southeast Section Conference.
[35] Department of Computer Science, The University of Nottingham, Nottingham, NG72RD,UK.MASSIVE: a Distributed Virtual Reality System Incorporating Spatial Trading.
[36] A Mobile Distributed Meeting Service based on Virtual Reality techniques. http://www.cyclovision.com.Feb.99.
[37] Roy Ladner, Larry Klos, Mahdi Abdelguerfi, Golden G.. Richard, A Distributed Virtual Reality Prototype for Real Time GPS Data
[38] J.M. Bishop. Virtual bodies and virtual spaces, http://www.emerald-librarv.com/ft.
[39] J.M.ZHENG, K.W.CHAN AND I.GIBSON. Desktop virtual reality interface for computer aided conceptual design using geometric techniques. J. ENG.DESIGN,2001, VOL. 12, NO.4,309-329.
[40] M.Iqbal,M.S.J.Hashmi. Design and analysis of a virtual factory layout. Journal of Materials Processing Technology 118(2001) 403-410.
[41] Randy S Haluck. Are Surgery Training Programs Ready for Virtual Reality?A
Survey of Program Direction in General Surgery. Haluck et al. Vol.193,No.6,December 2001 660-665.
[42] T.P.Grantcarov. Virtual reality computer simulation. Surgical Endoscopy(2001) 15: 242-244.
[43] By N. Okan, Metropolitan State University. Virtual Reality. Futurics Vol.25, No.3 & 4, 2001.
[44] M.Iqbal,M.S.J.Hashmi. Design and analysis of a virtual factory layout. Journal of Materials Processing Technology 118(2001) 403-410.
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