OpenFlight

Abstract: In the large-scale scene system based on scene management software, an efficient method was presented to render shadow with shadow volume algorithm. Approaches were discussed to convert scene model from openflight file to 3ds file. The data used to determine silhouette edge was obtained by accessing the simplest LOD of model A new method that reduced silhouette edge by removing redundant internal edge was provided. A new strategy of shadow rendering was presented: depending on model's position, shadows were rendered with z-pass algorithm utilizing CPU or z-fail algorithm within vertex shader. The method and strategy presented in this paper can be integrated directly into the large-scale scene system based on scene management software. The effect of shadow rendering meets the real-time and reality requirements of scene system.

Abstract: The present invention discloses an optimization view angle based ship production design drawing-inspection device implementation method. The method comprises the following steps: 1) on the basis of a principle drawing or installation drawing drawn by AUTOCAD and in combination with a tube part drawing and tube system coordinates, establishing a model in Tribo and converting a DWG file into a DXF file; 2) by interface conversion, directly converting the DXF file to an OpenFlight format, so as to obtain a tube system model that can be applied to a Creator or Vega virtual environment; 3) performing assessment on reliability and economy of the tube system model; 4) generating the tube system model in a drawing-inspection machine and a man-machine interaction observation feedback screen, so as to implement observing an internal structure of a ship body engine room tube system by a man-machine interaction function; 5) effectively discovering a problem during tube system construction by applying an optimization view angle method, and performing corresponding modification in a three-dimensional mode of a Pipe Modelling module of Tribon software after pointing out the model problem; and 6) completing modification, and obtaining a final ship engine room tube system. The method disclosed by the present invention is capable of optimizing ship tube system design, reducing ship design expenses and shortening the ship construction period.

Abstract: In order to satisfy the requirement of geometry modeling for virtual reality system, we process a modeling method based on CAD data. Firstly, the media file that is exported from the CAD data is parsed to gain the mesh data. And then the mesh data was simplified through the improved quadric error metrics algorithm, which makes better shape of triangle. At last, the mesh data is wrote to standard virtual reality model with lever of details via OpenFlight API. Ex- periments show that triangular mesh shape by our algorithm is more reasonable than QEM algorithm, but with higher quality of rendering. With large simplification, rendering frame rate and loading efficiency of model are high improved, and visualization of the virtual reality model almost have no change, which will be sufficient to meet the demand of virtu- al reality system.

Abstract: It is an important research topic to do the landscape design and evaluation, especially the pre-assessment, of high-speed passenger dedicated rail line effectively. This paper discusses the feasibility and necessity of using VR (virtual reality) technology to evaluate the high-speed railway landscape design comprehensively. For the rail line and ancillary facilities being the primary target of landscape design for high-speed railway, the building methods of them are studied in the first place. Based on an integrated analysis of the virtual landscape elements along high-speed rail line, a hierarchical structure of the landscape along the line is built, and a model database of ancillary facilities is established. Furthermore, with OpenFlight database, a standard data formats as a tool, the intelligent generation method of 3D rail track model is achieved. Then, using the Instances and External References and operating model data files through OpenFlight API's programming interface, the generation of ancillary facilities environment is accomplished.