FloodingDriven Modifications of a Hierarchical and Irregular Navigation Grid Structure for Large Virtual Terrains used in Simulation Systems Simulation systems are important tools for the development of training tasks in different application domains. The use of military simulated problems (MSPs) in simulation systems allows the introduction of challenging decision making situations to military trainees so that they can exercise their skills. To support the implementation of such MSPs in an artillery battery simulator, this work investigates how to compute dynamic changes, such as floodingdriven modifications, into the hierarchical and irregular navigation grid structure expressing the environmental characteristics of large virtual terrain scenarios. The paper describes an efficient mechanism to process these modifications during simulation runtime, without affecting the overall system response time, thus the user interaction with simulations. Experimental results show that the proposed techniques are able to handle timeconstrained modifications of large virtual terrain scenarios.

Research and implementation of multiscale dynamic terrain In the realtime rendering phase of terrain, there is the possibility of dynamic deformation of terrain, such as dynamic of surface elevation and color texture. In order to better effect the surface appearance, we use higher resolution to reflect the terrain deformation. This results in multiscale dynamic deformation in the terrain. In view of this situation, the maximum change region, namely the deformation region, is determined after the accuracy is improved. Then, we establish our own binary tree and DAG structure in the deformation region. Furthermore, the nested sphere of error metric is used to avoid the generation of crack and Tconnection. Finally, in order to give priority to the deformation region, the radius of nested sphere of error metric is used to constrain the error radius. The experiment proves that the algorithm can well reflect the deformation effect of the deformation area and meet the requirements of realtime terrain rendering after the local region has multiscale dynamic deformation.