Study On Three-dimensional Terrain Scene System Based On OpenGVS

In order to cooperate the investigation of land and resources, China Aero Geophysical Survey & Remote Sensing Center for Land and Resources (AGRS) is taking the project of virtual simulation for the Three Gorges. The project is aimed to simulate three-dimensional scene and to study some relative problems, such as geological slide, ecology environment, geological disaster, pollution control, etc. This paper is the preview study of the task. The three-dimensional terrain scene system of this paper design is aimed to establish three-dimensional virtual environment, and to establish scene interactive roam effectively.Virtual Reality (VR) is one of important techniques in computer advanced skillful field. VR use computer's technique of solid vision, feeling feedback, virtual stereo to realistically simulate people's visual, audible, touching action in element environment. VR can serve for many fields, such as Spaceflight, Medicine, Special training, Campaign rehearsing, Shopping and Architecture, etc. Virtual Geographical Environment (VGE) is produced by the combination of Virtual Reality techniques and Geography. VGE is the virtual reality based on the geo-analysis models and geo-project, which describes geography systematic space distribution as well as the virtual information geography world of process phenomenon established by geographical worker according to observation experiment and theoretical assumption.Scene simulation is the most important expression form of virtual realistic technical, it is to make users feel being personally on the scene; realize users and this environment to directly carry out natural interaction. Scene simulation with computer graph image technology, the purpose of simulation and structure of the three-dimensional model or reappearance actual environment, reaches very lifelike simulation effect. It is divided into simulation environmental production and simulation drive. Simulation environmental production includes mainly: model design, scene structure, veins design production and special efficacy design, etc. It demands to structure lifelike three-dimensional model and produce lifelike veins andspecial efficacy; Simulation drive includes mainly: scene drive, model transfer handling, distribution interaction and the large terrain handling, it demands to reappear lifelike simulation environment in a high speed, real-timely respond to interactive operating etc.The three-dimensional terrain scene system this paper has established scene interactive roam effectively (observing scene with arbitrary way), making users survey three-dimensional terrain from every angle; Trough scene romance, it reaches lifelike scene show, as well as carry out basic space analysis function in three-dimensional scene. Scene system to solve problem has two aspects mainly, the first is the three-dimensional virtual scene of the establishment, and the second is design of scene driving program. In view of establishing three-dimensional virtual scene, we consider that the area is comparatively large. So manmade building model completely is impossible, building model with machine may be used. Building model with machine is realized by Terra Vista(advanced software being used in building three-dimensional terrain database) with DEM, airscapes with scale of 1:10000 and vector data.Considering scene driver, we mainly carry out programming under VC++ environment with the combination of API OpenGVS offers. There are some problems:(l) realizing scene roam: going forward freely in virtual scene, rising-falling, retreating, accelerating, slowdown, turn in left or right; (2)realizing some special effects on disposal of scene, for example, halation and sky background;(3) realizing the space analysis of three-dimensional scene; (4) windows conformity; (5) dynamic input.Since scene system mainly apply Terra Vista and OpenGVS to carry out programming, so this paper introduced Terra Vista and OpenGVS in detail, depicted the performance and module function etc about two softwares. We emphatically discussed the crucial technology of realization and the specific design using OpenGVS SDK under VC environment. We have realized in program to dynamically input terrain data, conform windows, imitate control flight and the space analysis of three-dimensional scene etc. Simulation based on MFC has become a new trend, especially in development of programs that use OpenGVS and Vega as their scene management API. It has many...