Research On Lightweight Technology Of BIM Model On Web For Rail Transit

As a major innovation in the post-CAD construction field,BIM technology has played an important role in the construction industry,which is embodied in model visualization and simulated construction.In recent years,the development speed of rail transit has become faster and faster,and the use of BIM technology to accelerate the development has also become an inevitable trend.However,the traditional BIM visualization of rail transit only exists in modeling software,such as software such as Revit,which is a typical C/S mode,which does not meet the needs of construction personnel to quickly view the model and quickly interact with the model during actual construction.,Which hinders the development of the industry.Therefore,it has become particularly important to move the BIM model of rail transit from modeling software visualization to Web-side visualization,and to transform the traditional C/S visualization mode into B/S visualization mode.Based on the above requirements,the following work has been done:(1)Research on BIM lightweight and Webvisualization technology.Using the secondary development of Revit software,the surface model data of each professional BIM model in Revit is light-weighted and extracted,and the light-weighted data is saved in the JSON file format.At the same time,the FastDFS file server is selected to save the JSON file,and finally WebGL is used.Look for the data in the JSON file,and restore the BIM model on the Webbased on these data.(2)Research on the high-precision display method of BIM lightweight model.An optimization algorithm based on the Delunnary triangulation algorithm is proposed to calculate the lightweight geometric data(triangular patches)of the original BIM model to obtain a new set of triangles,and at the same time make the mesh average quality coefficient of the new set of triangles and The mesh correlation quality coefficients are better than the original triangle patch set,which improves the accuracy of the rendering model on the Web.(3)Research on collision detection method of BIM lightweight model.After rendering the model on the web side,because the pipelines in the professional BIM models are complex and prone to collisions,the automatic pipeline collision detection function is designed to help construction,and to solve the problem that Three.js does not support collision detection when roaming,it is based on Raycaster.The collision detection algorithm of the ray when roaming makes the actual experience when roaming.(4)Development of Weblightweight platform for rail transit BIM model.In response to the application requirements of the rail transit BIM model on the Webside,a detailed analysis,design,and implementation of a lightweight display platform for the BIM model on the Webside was implemented.After rendering on the web side,it meets the actual needs of on-site construction personnel for model viewing,rotating,selecting,viewing attributes,and roaming.