The Research And Design Of Dynamic Forest Growth Simulation System Based On HLA

The simulation of virtual forest aims at reflecting the real ecosystem, adopting virtual reality techniques to simulate the evolvement of forest zoology, and the outcome of the simulation can be used as a guide to the management of forestry production. While traditional forest simulation system favors the visual effect of the forest scene, there are two main problems in the design of system architecture and simulaiton entity modality: firstly, the faulty architecture neither supported the integrative simalation of entity modeling and functioning, nor the communication between different types of forest entity. Secondly, the granularity of forest entity was devided fallaciously. The modeling function layer and communication function layer were tightly coupled, which brought inconvenience on the design of physiology mathematical communication interface.To address the above issues, this thesis does its research work from three aspects as followed:Firstly, a dynamic-forest-simulaiton oriented architecture composed of simualtion application layer, communicaiton entity layer and grid infrastructure layer is presented, which adpots the combination of modularization and level-abstraction to integrate both the entity modeling and functioning.Secondly, different modality modeling algorithms are chosen for different forest entity model layer: trees are odeled by fraction and view-dependent muti-resolution model; terrains are simulated by regular square grid and view-dependent multi-resolution algorithms; sky is designed by skybox, skydome and skyplane algorithms and the water is created by time-based texture-mapping algorithm. Besides, the thesis makes further improvement on the realizaiton methods, and unifies the data-exchange interface between models.Thirdly, High Level Architecture (HLA) techniques are applied to provide the forest entity model with bio-mathematics communication interface, through which forest simulation entities could communicate with each other.As a result,the dynamic growing effect of a forest is reflected.Finally, the thesis analyses the limitation factors of forest simulation scale, and do some research on the application of open grid service architecture (OGSA) in the distribution design of communication entity.As the test result shows, the system presented by this thesis is efficient in simulating the dynamic forest-growing effect.