scholarly journals The Dual Half-Edge—A Topological Primal/Dual Data Structure and Construction Operators for Modelling and Manipulating Cell Complexes

2016 ◽  
Vol 5 (2) ◽  
pp. 19 ◽  
Author(s):  
Pawel Boguslawski ◽  
Christopher Gold
Keyword(s):  
Data Structure ◽  
Cell Complexes ◽  
Primal Dual

scholarly journals SPATIAL ADJACENCY ANALYSIS OF CITYGML BUILDINGS VIA 3D TOPOLOGICAL DATA STRUCTURE

2019 ◽  
Vol XLII-4/W16 ◽  
pp. 573-579
Author(s):  
S. Salleh ◽  
U. Ujang ◽  
S. Azri ◽  
T. L. Choon
Keyword(s):  
Data Structure ◽  
3D Models ◽  
3D Navigation ◽  
Topological Information ◽  
Cell Complexes ◽  
Connectivity Information ◽  
Different Dimensions ◽  
3D Topology ◽  
Topological Data Structure ◽  
Topological Data

Abstract. Adjacencies between objects provides the most basic connectivity information of objects. This connectivity information provides support for more complex 3D spatial analysis such as 3D navigation, nearest neighbour and others. In 3D models, the connectivity information is maintained by building a comprehensive 3D topology. As the international standard for 3D city models, CityGML employs a simple XML links mechanism that references related entities to each other as a means of maintaining topological information. This method fulfils the purpose of relating connected entities but, it does not describe how the entities are related or in other words its adjacencies. In this study, a 3D topological data structure was utilised to preserve topological primitives and maintain connectivity information for CityGML datasets of buildings in LoD2. The adjacencies tested in this study were based on the topological links maintained by the Compact Abstract Cell Complexes 3D topological data structure. Four types of adjacencies were tested which are Point-to-Line, Line-to-Surface, Surface-to-Surface and Volume-to-Volume adjacency. As a result, all adjacencies were able to be executed for both datasets which consisted of two connected buildings and disjointed buildings. It was found that the ability of the 3D topological data structure to preserve topological primitives and build topological links supported the maintenance of connectivity information between buildings. The maintenance of connectivity information was also not limited to objects of the same dimension and could extend to connectivity between building elements in different dimensions.

scholarly journals Modelling and analysing 3D buildings with a primal/dual data structure

2011 ◽  
Vol 66 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Pawel Boguslawski ◽  
Christopher M. Gold ◽  
Hugo Ledoux
Keyword(s):  
Data Structure ◽  
Primal Dual

scholarly journals Primal/Dual Mesh with Application to Triangular/Simplex Mesh and Delaunay/Voronoi

2012 ◽  
Author(s):  
Humayun Irshad ◽  
Stephane Rigaud ◽  
Alexandre Gouaillard
Keyword(s):  
Data Structure ◽  
Source Code ◽  
Primal Dual ◽  
Primal And Dual ◽  
Dual Mesh ◽  
As If

This document describes an extension of ITK to handle both primal and dual meshes simultaneously. This paper describe in particular the data structure, an extension of itk::QuadEdgeMesh, a filter to compute and add to the the structure the dual of an existing mesh, and an adaptor which let a down- ward pipeline process the dual mesh as if it was a native itk::QuadEdgeMesh. The new data structure, itk::QuadEdgeMeshWithDual, is an extension of the already existing itk::QuadEdgeMesh, which already included by default the due topology, to handle dual geometry as well. Two types of primal meshes have been specifically illustrated: triangular / simplex meshes and Voronoi / Delaunay. A functor mechanism has been implemented to allow for different kind of computation of the dual geometry. This paper is accompanied with the source code and examples.

scholarly journals Abstract Topological Data Structure for 3D Spatial Objects

2019 ◽  
Vol 8 (3) ◽  
pp. 102 ◽  
Author(s):  
Uznir Ujang ◽  
Francesc Anton Castro ◽  
Suhaibah Azri
Keyword(s):  
Data Structure ◽  
Data Structures ◽  
Main Idea ◽  
Visual Aids ◽  
Topological Information ◽  
Cell Cycles ◽  
Cell Complexes ◽  
Spatial Objects ◽  
Topological Data Structure ◽  
Topological Data

In spatial science, the relationship between spatial objects is considered to be a vital element. Currently, 3D objects are often used for visual aids, improving human insight, spatial observations, and spatial planning. This scenario involves 3D geometrical data handling without the need for topological information. Nevertheless, in the near future, users will shift to more complex queries corresponding to the existing 2D spatial approaches. Therefore, having 3D spatial objects without having these relationships or topology is impractical for 3D spatial analysis queries. In this paper, we present a new method for creating topological information that we call the Compact Abstract Cell Complexes (CACC) data structure for 3D spatial objects. The idea is to express in the most compact way the topology of a model in 3D (or more generally in nD) without requiring the topological space to be discrete or geometric. This is achieved by storing all the atomic cycles through the models (null combinatorial homotopy classes). The main idea here is to store the atomic paths through the models as an ant experiences topology: each time the ant perceives a previous trace of pheromone, it knows it has completed a cycle. The main advantage of this combinatorial topological data structure over abstract simplicial complexes is that the storage size of the abstract cell cycles required to represent the geometric topology of a model is far lower than that for any of the existing topological data structures (including abstract simplicial cell cycles) required to represent the geometric decomposition of the same model into abstract simplicial cells. We provide a thorough comparative analysis of the storage sizes for the different topological data structures to sustain this.

scholarly journals 3D Topological Validation of Compact Abstract Cell Complexes (CACC) Data Structure for Buildings in CityGML

2020 ◽  
Vol 7 (2) ◽  
pp. 25-32
Author(s):  
Syahiirah Salleh ◽  
Uznir Ujang ◽  
Suhaibah Azri ◽  
Tan Liat Choon
Keyword(s):  
Data Structure ◽  
Directed Graphs ◽  
3D Models ◽  
Full Potential ◽  
Topological Information ◽  
Cell Complexes ◽  
Adjacency Matrices ◽  
3D Topology ◽  
Topological Data Structure ◽  
Topological Data

3D models without the preservation of 3D topological information hinders the ability of 3D models to serve its full potential in terms of 3D analyses. The support of 3D topology is crucial for analyses that requires information regarding adjacencies and connectivity. One of the ways to maintain topological information is by implementing a topological data structure such as the Compact Abstract Cell Complexes (CACC) topological data structure. This paper demonstrates the topological validation for the implementation of the CACC topological data structure implemented for buildings in LoD2 CityGML. Directed graphs and adjacency matrices were constructed for the test datasets of buildings in CityGML. The in-degree and out-degree for all vertices were calculated based on the adjacency matrices. Based on the “Hand-shaking” theorem, the number of α₀-cycles of the CACC topological data structure which connects points to form 1D topological links was compared to the number of directed edges of the constructed directed graphs. Therefore, the implementation of the CACC topological data structure for buildings in LoD2 CityGML was found to be topologically sound.

Distributed Modeling Of Building Systems Through Cyber-Physical Integration

2019 ◽  
pp. 12-17
Keyword(s):  
Data Structure ◽  
Operating Conditions ◽  
Physical Models ◽  
Distributed Model ◽  
Physical Processes ◽  
Distributed Modeling ◽  
Distributed Models ◽  
Operating Modes ◽  
Building Systems ◽  
Important Practical Application

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.

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