3D Viewpoint Management and Navigation in Urban Planning: Application to the Exploratory Phase

Abstract

3D geovisualization is essential in urban planning as it assists the analysis of geospatial data and decision making in the design and development of land use and built environment. However, we noted that 3D geospatial models are commonly visualized arbitrarily as current 3D viewers often lack of design instructions to assist end users. This is especially the case for the occlusion management in most 3D environments where the high density and diversity of 3D data to be displayed require efficient visualization techniques for extracting all the geoinformation. In this paper, we propose a theoretical and operational solution to manage occlusion by automatically computing best viewpoints. Based on user’s parameters, a viewpoint management algorithm initially calculates optimal camera settings for visualizing a set of 3D objects of interest through parallel projections. Precomputed points of view are then integrated into a flythrough creation algorithm for producing an automatic navigation within the 3D geospatial model. The algorithm’s usability is illustrated within the scope of a fictive exploratory phase for the public transport services access in the European quarter of Brussels. Eventually, the proposed algorithms may also assist additional urban planning phases in achieving their purposes.

Identification of the Best 3D Viewpoint within the BIM Model: Application to Visual Tasks Related to Facility Management

“…Hence, we have designed and implemented a 3D viewpoint management algorithm in [16,17] which automates and supplies complete visibility of a set of 3D objects (extracted from spatial and/or semantical queries) within a 3D model. As a reminder, visualizing a 3D geometric object, i.e., any object located in a 3D universe (x,y,z) and built from one of the geometric primitives (point, curve, surface, and solid) defined within the spatial schema ISO 19107:2003 [18], requires a virtual camera, which acts as a real camera since it "converts electromagnetic radiation from an object into an image of that object and projects the image onto a surface" [19].…”

“…Finally, note that, in the case of computer animation combining multiple points of view, a vision time can be given to a 3D viewpoint. Figure 1 illustrates the previous parameters (from [17]).…”

“…A complete RESTful web application managing the 3D viewpoint. The 3D visualization process is carried out client-side (via WebGL) while the computation process is supplied server-side thanks to Node.js and three.js (from [17]).…”

“…A 3D viewpoint and its components: Camera position, orientation, focal length, and vision time (from[17]). …”

City Maker: Reconstruction of Cities from OpenStreetMap Data for Environmental Visualization and Simulations

“…Most often, 3D information is provided through hierarchical and semantically consistent formats [3,8]. Through such an arrangement, different applications, such as the ones for flooding [9][10][11] or urban development planning [12,13] can utilize the data according to their requirements. In addition, providing multiple layers and storing the data in a hierarchical structure, more details can be incorporated into city description, which is essential for realistic and complex scenarios.…”