Practical Research On 3D Scene Editing Technology

3D scene editing is not only an important researching content but also a researching hotspot and nodus in Virtual Reality, Computer Animation, and Computer Graphics. And it has an expansive application foreground in 3D Games, Movies, Specially Multimedia Production, and so on.3D scene editing includes two major parts. One is 3D scene modeling and the other is real-time rendering. Scene modeling is mostly composed of painting, producing, editing, storing, and managing of 3D virtual scene. The aim of all the above items is to provide a system with high-level scene editing function. Rendering refers to display the virtual scene which has been constructed, especially in the interactive fields that require quick responses.Since the complex scene has large data and needs real-time response, now the low rendering speed is a huge obstacle to 3D scene editing. There are two effective ways to enhance the rendering speed greatly. One is preprocessing the model representing the scene during the modeling period through the expanse of the structure of the scene graph. The other is making use of effective strategy and GPU which has perfect speed in solving the problem related to data-parallel computation during the rendering period.This thesis researches on the 3D scene editing, especially on the techniques related to rapid modeling, visibility culling based effective rendering and collision detection for the compounding and preview of scene. The detailed methods are shown as follow:(1) Utilize BSP tree to reorganize the scene graph. Decompose the leaf nodes of the scene graph from simple geometrical body into triangle meshes and store all of the mesh string in a set. Although this preprocessing brings more meshes more complex structure, it also facilitates the hided surface culling processing. The random algorithm employed in the generation of the BSP tree enables the establishment of the BSP tree of scene in an expected time.(2) Implement a front-to-back algorithm based on occluder replacement. The algorithm predefine the occluder, which is the object of an occlusion tree, and render the scene based on BSP tree from the near to the distant. On this basis, realize an incremental approach applied in the dynamic scene rendering.(3) During the 3D scene editing process, customer will want to adjust and view the 3D scene real time. Especially during the late tailor process, some operations such as compounding scenes or animation generation basing on key frame interpolation, must detect collision according to the possible paths which objects may use to move along. This thesis proposes two methods for collision detection. One is a basic collision detection method basing on BSP tree, the other is a collision detection method basing on optimized BSP tree.The main shortage of this thesis is the lack of a good interactive operation method. During the 3D scene editing, customer deals with the model via the matrix operation of the exchange nodes. This may be an extortionate requirement for the customer, so it is necessary to design a good interactive operation mode to make the custom use the scene editor more conveniently and easily. For more, this scene editor also should include apparent generation of In-Between Frames. All of these will be further worked on.