Research And Implementation Of Visual Platform Of Three Dimension Bridge Based On WebGL

Following the continuous advancements in science and technology and the constant expansion of bridge design and construction scale in recent years,the number of bridge projects executed by adopting information collaborative management to synergize the entire life cycle of the project has also increased.A 3D bridgevisualization platform can provide technical support for information sharing among different management levels in bridge engineering and more intuitive and detailed 3D information design on bridge construction,which will effectively improve the quality and efficiency of bridge engineering.This thesis leverages the Web Graphics Library(WebGL)technology and the open-source engine three.js,employing the programmable rendering pipeline provided by WebGL,the 3D displaying function of three.js,and the geographic information function of Cesium to develop a 3D bridge visualization platform that achieves the following: the 3D parametric modeling of a bridge;the 3D geographic environment drawing of a bridge;and the 3D visualization of bridge construction.The main contributions of this thesis are summarized as follows:(1)3D parametric modeling of bridges.The thesis applies point-cloud modeling and three.js to construct the geometry modeling method.First,the main key points of the bridge section are obtained according to the bridge section parameters.Second,the point-cloud information of the bridge section is calculated based on the main key points and leveraged to realize the control of the bridge.Finally,the cross section of the bridge is swept along the bridge axis to complete the 3D parametric modeling of the bridge.(2)3D geographic environment drawing of bridges.The thesis uses the level of detail(LOD)technology to draw a 3D virtual earth.The terrain of a bridge is drawn using the LOD model algorithm and the LOD model selection algorithm.Ultimately,the 3D geographic environment drawing of the bridge is completed by combining the terrain cache mechanism based on Quadtree.(3)3D visualization of bridge construction.Following the design of the extra-large bridge in Zhengwan Railway Zhaohe Town across the south-to-north water Diversion canal,the selection of the bridge model is realized using a collision detection algorithm.The quaternion matrix is used to update the construction status of the bridge,and the 3D visualization of virtual bridge construction is achieved.(4)Using the interactive function module and visualization function module,the 3D bridge visualization platform,the virtual earth image,and the 3D bridge model are realized.Based on the cross-platform feature of Java,the 3D bridge visualization platform is operated across different operating systems,and the functional modules of the platform are tested and verified on a computer and mobile phone.