面向手机网页的大规模WebBIM场景轻量级实时漫游算法

Mobile web-based lightweight and real-time roaming algorithm for large-scale WebBIM scenes

当今,使用手机网页来访问大规模建筑环境逐渐被人们所追求.BIM(building information modeling)是新一代智能建造的核心技术.本文以其主流格式IFC(industry foundation classes)作为输入数据格式,提出一套面向手机网页的大规模Web BIM场景实时漫游算法.与图形学领域的可视化程序相比,该方法不只注重可视化渲染时的面片级处理,更是在遵从建筑语义的前提下,以建筑构件为单位,对大规模Web BIM场景进行轻量化处理.方法主要从构件实例冗余、构件及空间混合索引、多粒度数据动态装/卸载策略3方面对场景数据量、组织结构、动态数据管理进行优化,并集成到原型系统.实验表明本文方法的去冗比例达70%左右,原型系统的FPS能保持在30左右,内存损耗约400 MB,能较稳定、流畅地在手机网页上进行大规模Web BIM场景的实时漫游.

With the popularity of mobile terminals,including smart phones,there is a great push for users to share large-scale data on phone webpages.This study considers building information modeling（BIM） as the core smart construction technology and leverages,its classical data format — industry foundation classes（IFC） as the input data format,and presents a mobile web-based lightweight and real-time roaming algorithm for large-scale Web BIM scenes.To comply with the semantics information in IFC files and with a building＇s structure,our method focuses on creating a more lightweight product,by not relying exclusively on geometry faces as ordinary visualization programs do.Our main idea for optimizing mobile,web-based,lightweight and realtime roaming is threefold：reduce redundancies,generate an efficient hybrid data structure and design dynamic load/unload strategies.In the study,a prototype system was integrated and leveraged for experimentation.The final performance analysis shows that we can significantly reduce the redundancy to about 70 percent of the raw BIM scenes.Meanwhile,our method can maintain the FPS at around 30 and memory consumption at about 400 MB with an increasing scene scale.