The Design And Implementation Of 3D Building Model Visualization System Based On WebGL

With the development of the Internet and the arrival of the intelligent era,various industries and fields have gradually become informatization,industrialization,and intelligence.The construction industry has been low in the level of industrialization due to the involvement of multiple professional fields,the need for collaborative work,and large engineering volume.At the same time,Chinese aging problem is serious,and the demographic dividend disappears.The government has begun to push the prefabricated building.In the process of accelerating the development of the assembly-building industry,the three-dimensional building information model is an important product to improve the level of informationization in the construction industry and serve the entire life cycle of the building.The high precision and high information direction of the 3D building model also bring new challenges to the display of architectural models,so a lightweight way is needed to realize the model display.So far,the industry has designed some solutions for building model display problems,but these solutions still have the disadvantages of requiring plug-ins,poor compatibility,low rendering efficiency,and poor interaction.Therefore,in order to solve the problem that the architectural model format is not uniform,the lightweight of BIM and cross-platform visual interaction issues without plugins,and improve the sharing of 3D building models,this thesis uses WebGL technology with open source,cross-platform,hardware acceleration and other related technologies to complete the design and implementation of 3D building model visualization system based on WebGL.The main work content has the following four aspects:1)Storage of building information model: Since the format of complex architectural models is not uniform,WebGL cannot directly load and render.Therefore,this thesis uses a multi-document file format for storage.In the process of extraction,different information is stored in different files or databases.2)Lightweight of building model: The building model is large in volume and contains a lot of redundant and non-rendering information.Therefore,the thesis is used to deal with it,at the same time,it is observed that the model contains a large number of components with different positions but the same model type,this thesis adopts the method of storing the unique components and other relative transformation matrices to remove the duplicated components and realize the lightweight processing of the model.3)Design and implementation of modular rendering framework: The process is more cumbersome for developing programs directly with WebGL,so this thesis uses Three.js,the existing open source library based on WebGL,on the basis of which,the modular idea is used to design and implement the rendering framework of the building model,which completes the loading and rendering of the model and facilitates the later expansion work.4)Document permissions: There are different models in different projects,and there are different people in the same project.In order to improve the security and sharing of the building model,the user's document permissions are designed and implemented,and the user's operations are strictly restricted.The 3D building model visualization system designed and implemented in this thesis has been integrated into the assembly collaborative platform for the actual project operation.The actual application results show that the system solves the cross-platform sharing of the building model and visual interaction problem.