Key Techniques Of Visualization Models System On Military Simulation Entities

Visual data models(VDM) on military simulation entities was an important part of military simulation display system, which was the basis of 3D display system of battlefield situation, military simulation system and Command Automation System, providing the support of data and models for the weapon system evaluation and computer generated forces (CGF). The models gave an impulse to make use of information technology and the conception of NCW(Network Centric Warfare), developed the joint C~4ISR architecture and realize combat capability based on visual full spectrum.With concerns of visual data models on military simulation entities, the paper discussed the role of VDM in military simulation system .By analyzing the processes, management and application of VDM modeling, the general frame and functions of VDM on military simulation entities were established. Finally, the practical projects were presented.1. Categorization and hierarchical architecture of visual data model on military simulation entities was presented.According to the requirement of visualization in military simulation system, categorization methods of VDM on military simulation entities were proposed. VDM were classified by 4 kinds of models, such as combat entities, command entities, synthetic natural environment and military topology, which offered convenience of the creation, management and use of VDM. By analyzing the processes, management and application of VDM modeling, the overall structure and functions of VDM on military simulation entities were constructed. It comprised 8 layers of geometry and data: panorama level, integrated level, object level, surface level, vertex level, topological relations level, attribute level and action level, and analyzed characteristic and function for each level in order to improve VDM storage management. To facilitate of the application of various VDM, cut down repetitive works, and speed up the display and rendering pace, model-rules on grouping, multiresolution, grades of damage and texture rules were constituted. By adopting categorization methods and hierarchical architecture of VDM, it was helpful to implement fast rendering in three-dimensional scene, and it also could identify information about levels of military simulation entities quickly. Hierarchical architecture of VDM could control the dynamic display level of models by the management of hierarchical details. The problems of aggregation and disaggregation in military situation expression initially were solved as well.2. The architecture of VDM management system on military simulation entities was proposed.According to the concept of modern software engineering and the importance of VDM and data management in military simulation system, the architecture of VDM management system on military simulation entities was proposed. The techniques involving special database and relational database were synthesized to build the data storage and maintenance framework .Furthermore, the data storage structures for each level architecture were constructed, and, the algorithm for reconstructing VDM was designed and realized as well. The organization and management of established models was used during three phases: modeling, post-processing, and application. The visual process of data acquirement, modeling, disposal and its application was implemented. Hereby, these models could satisfy the requirement of VDM in the military simulation system. By VDM data management system, database storage technology was realized. The experiment showed it can solve compatibility and data exchanging issues between different entities. To describe the relationship during attributes, mutual entities or other factors, the VDM database should be established consistently and integrally. The system included modular and hierarchical design and VDM' s database establishment, maintenance, display, transfer, dynamic control and visual display .The models not only had many advantages, such as real 3D environment, clearer logic-tier and high resolution, but also could analyze parameters of tactical guide for combat entities, which can be embedded generically in military simulation system to improve the reusability of models.3. The technology of creating multiresolution was discussed about large-Scale battlefield terrain environment.According to the character of synthetic element in the battlefield terrain environment, such as large quantity of data, the complicated terrain, irregularly shape, multiresolution, considering the concept of restricted quad-tree and progressive meshes, an algorithm of real-time dynamic triangulation based on restricted quad-tree for large scale terrain visualization was discussed. In terms of view-port抯 position of and the directions of sight, an algorithm similar to prototype for mesh dynamic Simplification could come true by deleting little important vertexes and triangles or inserting more important vertexes and triangles . Propose a method of progressive meshes based on restricted quadtree between blocks of different resolution, and the real-time dynamic triangulation controlled by giving view dependent error come true. The method could speed up the speed of 3D scene roaming and solve such problems which can抰 be satisfied the demand of terrain visualization based on RMI. The experiments showed that this algorithm was less network costs and overleaped data structure and operation details. Furthermore, it was very good of the real-time LoD controlling for large scale terrain visualization and also for the real-time rendering.4. A real-time Simplification technology of VDM on military simulation entities was researched.This research analyzed VDM抯 function on military simulation system and the characteristic of VDM of action entities. To preserve the topology structure and attribute features of the model, it summarized the simplification algorithm with attribute feature of models oriented action entities, and proposed the simplification method based on half-edge collapse operation and local error tolerance, which constructed multi-resolution models. Three factors of geometric error metrics, including the length and dihedral angle of the collapse edge, the distance between vertex and adjacent plane were referred in this algorithm. By introducing the weight of attribute feature, the total error with geometric errors and attribute errors combined was simplified, and the validity for the simplification quality was examined.Attribute information such as model抯texture had been preserved, and solved the display problem about 3D visual scene in military simulation system initially, in order to achieve the purpose of reality and fluency.Compared the algorithm with other typical simplification method by average error, max error, simplification of time, and the characteristic of geometry and attribute preservation, test demonstrated that the algorithm was efficient for the geometric and attribute feature of the model maintenance, and played an important role in improving fidelity and fluency of 3D scenes.