The Research On Computer Simulation Method Of Artificial Sky Hemisphere

With the development of economy and technology, people are paying more and more attention to the building environment, among which insulations environment is more closely bound up with people's life. As an important way of day-lighting research and education, the artificial sky hemisphere has been widely used in many colleges and institutes, because it is free from the influence of outdoor climate and can simulates the conditions of the real sky in some way. Further more people can research the shadow and solar energy utilization within or between building models under reduced scale by putting them under the hemisphere.But there are several problems in the artificial sky hemisphere when it is used as a sky model. Firstly, the brightness of inner surface of artificial sky hemisphere can not accurately reflect the true distribution of the real sky while lighting resources are installed along the lower edge of the hemisphere. Secondly, it is hard to simulate the immediately change of light-color in the sky within the artificial sky hemisphere because the lamps constant. Thirdly, because the large equipment needs regular daily maintenance, occupies huge indoor space and needs exact building model, it is not so convenience and cheep enough to be equipped easily.In the paper a three dimensional virtual sky hemisphere on computer is established and a set of building model based on AutoCAD or 3DS MAX is put into the sky model, and a calculating program is given in computer combined with light-environmental, geographical, meteorological, and many other data. The program has been developed from Autodesk 3ds max, and used 3D virtual technology to achieve a real sky, solved geographical choice, light-climatic choice and light color changes at the same time. The system also adopts multi-angle and multi-directional effect export in order to improve the experimental results of visualization. Meanwhile, the system not only applies the powerful modeling capability of 3DS MAX, but also provides users with a more convenient and efficient modeling methods.This simulation system of artificial sky hemisphere gives a new way to enhance the education and research work efficiently.