Research And Realization On Key Technologies For 3D Model Services Based On GlTF

With the development of HTML5,the realization of interactive 3D geography applications which are across devices,cross-platform and plug-free has a good foundation.However,with the rapid development of 3D model acquisition technology such as 3D modeling technology and 3D scanner,the number of 3D models shows a trend of geometric growth.Due to the complex structure and various types of 3D models,the 3D model hasn't have a standard format.A large number of existing 3D model formats are flawed in terms of content integrity,coding performance and openness,and are difficult to convert each other,which seriously affects the sharing and reuse of 3D assets.There are also many problems in 3D city models.For example,due to the complexity of models' structure,and the high demand of network transmission,the visualization of 3D city models still lacks a corresponding solution.In view of the above problems,this dissertation puts forward a solution,which selects gl TF as standard 3D format and constructs 3D tiles pyramid based on gl TF.The work done in this dissertation is as follows.(1)Various elements in gl TF are studied.And an optimization scheme to reduce gl TF file footprint is proposed.(2)An approach to achieve the conversion from other model formats to gl TF is proposed,which uses Collada as the intermediate model format.The software that converts Collada to gl TF is designed and implemented.Functions,completeness and processing efficiency of the software are tested.(3)A scheme that realizes the visualization and management of gl TF is proposed.A OSG plugin that visualizes gl TF and a gl TF assets manager based on Three.js are designed and implemented.The functions of plugin and assets manager are tested.(4)A technology called 3D tiles that merges gl TF assets and attributes is proposed.The software that realizes main data porcessing steps from gl TF to 3D tiles is designed and implemented.All functions of the software are tested.(5)A scheme for organizing and managing 3D tiles is proposed.The structure of 3D tiles pyramid is designed.The construction and visualization of 3D tiles pyramid are implemented and tested.In summary,this dissertation constructs 3D model services of processing,management and visualization based on gl TF,designs the structure of 3D tiles pyramid and implements the construction and visualization of 3D tiles pyramid.The content of this dissertation has great reference significance for reusing,managing and visualizing 3D city models.