建筑信息模型的Web端重建与三维交互方法研究

在BIM技术的背景下,针对现有的BIM服务器多为C/S架构,对电脑软硬件有较高要求、无法跨平台等问题,实现BIM模型在Web端的重建,并实现了对模型的拾取,获取其属性。其方法主要分为两部分,第一部分实现BIM模型从Revit软件中的导出,第二部实现对其导出的模型信息在Web端的三维交互,具有良好的用户体验。     

三维可视化技术在城市燃气数字化治理的应用

通过分析游戏引擎、WebGL、三维GIS三维可视化技术的特点,从数据类型、成本投入、项目特点、应用需求方面研究城市燃气三维数字化治理方案的技术路线,给出3个城市燃气三维数字化治理方案的典型案例。     

Web端快速加载BIM模型的方法研究

为了在新冠疫情期间减少人员接触,并鼓励开发企业利用互联网、虚拟现实(VR)和直播售楼等非接触方式开展线上楼盘展示,提出了以BIM模型为基础,将BIM模型的IFC标准转换为适用于网络传输的3D Tiles标准。该方法主要分为IFC-OBJ、OBJ-glTF和glTF-3D Tiles三个步骤,并选用开源平台Cesium作为加载BIM模型的框架。实现了BIM模型在Web端的快速加载,并且减少了几何信息和属性信息丢失的情况,为开发企业提供新的营销方案。     

基于Unity引擎的土木工程专业Web3D模型开发

介绍了基于Unity引擎的土木工程专业Web3D模型的开发流程,阐述了Web3D模型的主要功能与实现方法,并说明了已开发的Web3D模型的特点及其作用,指出采用Web3D模型克服了传统教学媒体的不足,取得了良好的效果,具有广阔的应用前景。     

基于DirectX的三维地理信息引擎设计与实现

通过分析国内外三维地理信息系统技术现状,提出了基于DirectX实现三维地理信息引擎的架构设计,并在此基础上自主开发了三维地理信息引擎Spatial3D,并成功应用于沙盘展示、应急演练、GPS跟踪等多个业务领域.     

基于城市设计的三维地理信息系统研究

计算机技术和虚拟现实技术的飞速发展,促进了三维数字技术在城市规划中的广泛应用。利用三维地理信息系统进行城市规划已经成为我国城市规划信息化的主流发展方向。本文针对三维场景建模的要素和构建方法进行了较为详细的介绍,并就三维地理信息系统及其功能的设计进行了阐述,以期为科学的城市规划提供有效的借鉴。     

基于A3航空摄影系统和Smart3d软件快速进行实景影像三维模型生产

当今社会,数字城市建设飞速发展,对城市实景影像三维建模需求越来越多,A3数字航摄仪以其独特的优势能快速辅助城市实景影像三维模型生产。本文以天津重点区域为例,利用先进的A3数字航摄仪,结合Smart3D软件,详细阐述了从数据获取到实景影像三维模型制作的过程。     

“数字合肥三维城市景观系统”的建设与应用

三维地理信息系统的应用越来越广泛和深入,本文介绍了“数字合肥三维城市景观系统”的建设情况,并就系统在城市规划管理中的应用进行了探讨。     

基于激光扫描技术的室内外三维场景构建方法

由于各种大规模室内活动场所的建立,传统二维地图的导航定位已不可能完全满足人们的需求,且室内定位技术的研究与发展对室内外一体化高精度三维地图的制作提出了更高的要求。本文以河北野三坡服务区主楼为例,探讨性提出了一种针对室内外导航定位的三维场景快速构建方法。首先布设室内外一体化高精度坐标控制网,其次利用三维激光扫描技术获取实际地理坐标的高精度点云数据,运用3DMax软件对主楼室内外精细建模,并融合周边DOM、DEM等数据在Skyline软件中构建可交互式操作的可视化三维场景进行发布。结果表明,该方法可快速准确获得室内外全景环境及任意处的位置坐标。     

一种三维城市场景的快速裁切算法

为了便于城市三维数据的分发与应用,通常需要根据用户的需求提取指定范围的三维场景.目前,三维GIS领域缺少针对城市大范围三维场景的快速裁切算法.本文在对三维场景进行分层分块组织的基础上,提出了一种图层过滤、分块筛选、模型裁剪的快速裁切算法.多个城市的应用实践证明,该算法准确、高效,适用于城市大范围三维场景的快速裁切.     

基于AR的互动式3D电子书的研发与实现

增强现实(Augmented Reality,AR)电子书是在传统纸质书籍的基础上,将计算机处理过的虚拟信息叠加在真实场景上,并借助感知和显示设备,将虚实信息融为一体,在显示静态模型的同时播放声音,从而显示虚拟三维景象的电子图书。本文阐述了使用ARTool Kit开发包和Open GL进行3D电子书的开发过程,在完成基本功能的同时改变模型加载方式,扩展了标识图的单一识别功能,展现了一个多样化的增强现实的发展和应用。系统使用不同的建模软件建立模型,并进行渲染加载,完成声音展示,使其更加生动贴近现实,提高了阅读者的阅读兴趣。该互动式3D电子书弥补了传统图书的不足,体现了增强现实电子书的独特优势,是增强现实在教育领域的一种有益应用,具有极大的市场价值和科研价值。     

基于XML的Web信息采集系统设计与实现

设计基于XML的Web信息采集系统,抽取出HTML页面中半结构化数据后,将清洗、解析后的数据置入My SQL数据库中。通过将类型相似页面的节点信息和字段描述配置于XML文件中,改进了网页对应独立抽取模板的方法,有效地提高了Web信息采集的效率和准确性。实验结果表明,基于XML的Web信息采集系统能够满足信息抽取的需求。     

Multi-view stereo for weakly textured indoor 3D reconstruction

A 3D reconstruction enables an effective geometric representation to support various applications. Recently, learning-based multi-view stereo (MVS) algorithms have emerged, replacing conventional hand-crafted features with convolutional neural network-encoded deep representation to reduce feature matching ambiguity, leading to a more complete scene recovery from imagery data. However, the state-of-the-art architectures are not designed for an indoor environment with abundant weakly textured or textureless objects. This paper proposes AttentionSPP-PatchmatchNet, a deep learning-based MVS algorithm designed for indoor 3D reconstruction. The algorithm integrates multi-scale feature sampling to produce global-context-aware feature maps and recalibrates the weight of essential features to tackle challenges posed by indoor environments. A new dataset designed exclusively for indoor environments is presented to verify the performance of the proposed network. Experimental results show that AttentionSPP-PatchmatchNet outperforms state-of-the-art algorithms with relative 132.87% and 163.55% improvements at the 10 and 2 mm threshold, respectively, making it suitable for accurate and complete indoor 3D reconstruction.     

某列车送风系统及车室内气流组织优化研究

应用理论定性分析、CFD模拟和实验研究3种方法研究了某高速列车送风系统送风的均匀性及车室内的气流组织情况.首先,依据列车实现均匀送风的原理及方法,对列车的送风系统进行定性分析,提出在列车内加调节板的具体实施方法.其次,将定性分析的结果应用于CFD模拟,通过对调节板高度和调节板位置的数次仿真调整,最终使列车送风系统的送风不均匀系数明显下降,列车车室内的速度场和温度场符合铁标TB 1951—87中要求.最后根据列车实际尺寸搭建原型实验台,将实测值与模拟值进行对比分析,并用不均匀系数和空气分布特性指标对改进工况下的实验值及模拟值进行评价.     

基于Web3D的倾斜三维实景模型漫游系统实现

针对目前倾斜三维实景的展示,只能局限在本机中浏览特定存储的场景及受众面窄等问题,在分析三维实景可视化关键技术的基础上,将倾斜摄影测量采集并重建的安徽财经大学三维实景模型,利用Cesium平台实现在浏览器上漫游和查询倾斜三维实景模型以及相关信息。该系统构建简单,使用户脱离专业设备和软件的限制,浏览查询更加方便,提高了倾斜三维实景模型的使用率。     

Door detection in 3D coloured point clouds of indoor environments

Door detection is becoming an increasingly important subject in building indoor modelling owing to its value in scan-to-BIM processes. This paper presents an original approach that detects open, semi-open and closed doors in 3D laser scanned data of indoor environments. The proposed technique is unique in that it integrates the information regarding both the geometry (i.e. XYZ coordinates) and colour (i.e. RGB or HSV) provided by a calibrated set of 3D laser scanner and a colour camera. In other words, our technique is developed in a 6D-space framework. The geometry-colour integration and other characteristics of our method make it robust to occlusion and variations in colours resulting from varying lighting conditions at each scanning location (e.g. specular highlights) and from different scanning locations. In addition to this paper, the authors also contribute a public dataset of real scenes along with an annotated ground truth. The dataset has varying levels of challenges and will help to assess the performance of new and existing contributions in the field. The approach proposed in this paper is tested against that dataset, yielding encouraging results.     

基于AutoLISP的三维模型快速建立与精度分析

建筑物的三维模型是数字城市重建的重要组成部分,而建筑物高精度三维模型的快速建立一直是三维数字仿真亟待解决的问题。本文通过无协作目标电子全站仪采集建筑的三维坐标,基于AutoLISP实现了数据的导入、建筑物墙面的拟合、特征点的投影及门窗等构件的自动生成,从而快速生成建筑物的三维模型,并对生成的建筑模型进行精度分析。基于AutoLISP构建建筑物的三维模型,大大提高了建模速度;并能有效控制三维建筑模型的质量。     

Intelligent generation of indoor topology (i-GIT) for human indoor pathfinding based on IFC models and 3D GIS technology

Indoor topology is the basis for most indoor location-based services, such as wayfinding in shopping malls, escape route planning, and passenger transfer in transport stations. Currently, however, indoor networks for wayfinding by people have not yet been developed to a standardized representation as street maps have been, but many studies have attempted to develop indoor network models for indoor LBS.A complete indoor network includes both floor-level paths and non-level paths, such as stairs, elevators, escalators, ramps, and so on. Most existing studies, however, have explored floor-level paths; few studies have considered non-level paths. Many studies have used 3D building models based on Industry Foundation Classes (IFC) to develop algorithms for generating paths, but most of them require the IFC model to contain semantic elements for the spatial relationships among building components, which means extra efforts are needed when preparing the IFC Model from the original building model. Moreover, most algorithms dealing with floor-level paths use simplified floor plans as the input, which are different from the real data retrieved directly from IFC models. All of these requirements and assumptions add to the cost of producing an indoor network.In this study, we propose an approach called i-GIT to produce a graph-based indoor network including floor-level and non-level paths from IFC-based building models. i-GIT requires only the geometric information of IFC data models to automatically identify indoor space boundaries as well as to produce six categories of indoor paths. The innovation of this study is that it includes novel algorithms to produce non-level paths, and introduces the polygon regularization on indoor space boundaries to reduce the number of excessive nodes before applying Constrained Delaunay Triangulation to produce level paths.Three campus buildings and a Taiwan High Speed Rail (THSR) station were chosen to validate the proposed approach. Multiple OD pairs in one of test cases were randomly selected to find the shortest routes using the paths generated by i-GIT. Compared with paths manually drawn using the principles of Medial Axis Transform (MAT) and the route lengths from actual measurement, the average path availability is higher than 96%, while the average error of route lengths based on generated paths is approximately 5%. The results showed that i-GIT was able to accurately and effectively produce a complete indoor network.     

民初中日冲突事件中的共同调查:以昌黎事件为例

昌黎事件发生于1913年(大正二)年9月11日,是驻守昌黎车站的中国巡警与日本驻屯昌黎守备兵之间发生的冲突事件。该事件造成中国方面以巡长为首五名巡警被日本守备兵枪杀的严重后果。事件发生后,中国提出中日两国关于事件的共同调查请求,日本虽然积极应对,但两国调查委员不仅关于事件的报告检讨未能达成一致意见,在现场调查、证人证言等方面双方意见也完全相左。关于调查的结果,双方仅仅在车站内斗殴、日本守备队采取了行动这两点上形成共识,其余决定性的事实仍然无解。究其原因,显然与日本陆军一贯的强硬态度不无关系,而更深层原因一方面是:日本陆军及民间右翼势力所制造出的国内对华强硬的舆论压力;另一方面则是,山本内阁成立后,追随政友会及第二次西园寺公望内阁的内政外交政策,在处理国内外问题上,被舆论及陆军势力所左右。     

新型3D-SCADA系统的设计与实现

为提高消防水系统安全的可控性,降低管理和维护成本,并在火灾发生时提供及时的救援决策支持,提出并实现了一种用于消防水系统智能监控的3D-SCADA系统。在分析SCADA系统特殊性的基础上,建立系统构架。介绍远程终端单元和前置机的软硬件设计,并探讨3D-SCADA系统上位机软件功能、设计和实现。