Print Email Facebook Twitter Modeling a 3D City Model and Its Levels of Detail as a True 4D Model Title Modeling a 3D City Model and Its Levels of Detail as a True 4D Model Author Arroyo Ohori, G.A.K. Ledoux, H. Biljecki, F. Stoter, J.E. Faculty Architecture and The Built Environment Department Urbanism Date 2015-07-02 Abstract The various levels of detail (LODs) of a 3D city model are often stored independently, without links between the representations of the same object, causing inconsistencies, as well as update and maintenance problems. One solution to this problem is to model the LOD as an extra geometric dimension perpendicular to the three spatial ones, resulting in a true 4D model in which a single 4D object (a polychoron) represents a 3D polyhedral object (e.g., a building) at all of its LODs and a multiple-LOD 3D city model is modeled as a 4D cell complex. While such an approach has been discussed before at a conceptual level, our objective in this paper is to describe how it can be realized by appropriately linking existing 3D models of the same object at different LODs. We first present our general methodology to construct such a 4D model, which consists of three steps: (1) finding corresponding 0D–3D cells; (2) creating 1D–4D cells connecting them; and (3) constructing the 4D model. Because of the complex relationships between the objects in different LODs, the creation of the connecting cells can become difficult. We therefore describe four different alternatives to do this, and we discuss the advantages and disadvantages of each in terms of their feasibility in practice and the properties that the resulting 4D model has. We show how the different linking schemes result in objects with different characteristics in several use cases. We also show how our linking method works in practice by implementing the linking of matching cells to construct a 4D model. Subject level of detail (LOD)4Dmulti-dimensional GIS4D data structureOA-Fund TU Delft To reference this document use: http://resolver.tudelft.nl/uuid:56801199-977f-491a-a209-6fb967137451 Publisher MDPI ISSN 2220-9964 Source https://doi.org/10.3390/ijgi4031055 Source ISPRS International Journal of Geo-Information, 4 (3), 2015 Part of collection Institutional Repository Document type journal article Rights (c) 2015 The Author(s)This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Files PDF ArroyoOhori_2015.pdf 237.82 KB Close viewer /islandora/object/uuid:56801199-977f-491a-a209-6fb967137451/datastream/OBJ/view