Lightweight Research Of Revit Model

From the generation of BIM technology to the continuous promotion,more and more building practitioners learn and apply it.Revit software has been favored by many architects as the main modeling software of BIM technology.However,new problems are also generated in the process of applying it,such as requiring ultra-high computer configuration,system crash when opening a large amount of Revit model,unable to meet non-designer’s view of model details.The idea of lightening these problems has emerged.In this context,this paper expands the lightweight research of the Revit model.With the development of WebGL technology,most major browsers support WebGL,which makes it possible for the model to display on the browser side.This paper combines Revit secondary development technology with WebGL technology to develop a Revit lightweight model display platform.The difficulty of the research lies in the transformation of the geometry of the Revit model and the rendering optimization of the model.main tasks as follows:(1)Model lightweight processing and data structure transformation.The Revit model is used to develop the Revit model as an IFC model file.Quantize the data structure of the model and JSON format file,and use the model data export interface function to redevelop the Revit software to realize the export of the model data and the conversion of the Revit model data structure to the JSON data structure.(2)Realize the geometric transformation and lightweight display of the Revit model.Through the research of WebGL rendering framework,choose Three.js as the rendering framework of Revit model.The ObjectLoder function is used to convert the model into a triangular patch to realize the geometric transformation of the Revit model.Combining the WebGL technology and the Three.js rendering framework,the Revit model is rendered on the browser side for lightweight display.(3)Realize the 3D interaction of Revit model and the query of attribute information.Study the principle of the trackball and design the mouse click event to realize the three-dimensional interaction of the model through the TrackballControls.js trackball.The basic principle design of the ray intersection method is designed to realize the query of the model attribute information.(4)Implement rendering optimization for the Revit model.Aiming at the contradiction between limited computer resources and large-scale Revit model with massive data,the linear octree algorithm and LOD algorithm design OcLOD rendering optimization algorithm are studied to improve the rendering rate without affecting the accuracy of the model.Through the testing of the lightweight platform,the Revit model lightweight display platform developed in this paper not only has good effects but also has a good three-dimensional interactive experience,which has engineering significance and practical value.