Christopher M. Gold

Euler Operators and Navigation of Multi-shell Building Models

This work presents the Dual Half Edge (DHE) structure and the associated construction methods for 3D models. Three different concepts are developed and described with particular reference to the Euler operators. All of them allow for simultaneous maintenance of both the primal and dual graphs. They can be used to build cell complexes in 2D or 3D. They are general, and different cell shapes such as building interiors are possible. All cells are topologically connected and may be navigated directly with pointers. Our ideas may be used when maintenance of the dual structure is desired, for example for path planning, and the efficiency of computation or dynamic change of the structure is essential.

Rapid Indoor Data Acquisition Technique for Indoor Building Surveying for Cadastre Application

2D cadastre has been in existence for decades and most countries have found it convenient. However, in complex situations it has been found to be inadequate as ownership becomes difficult to realise. 3D cadastre data was previously not being collected, thus, making such data even more difficult to realise. 3D data collection for 3D cadastre is one of the main issues for practicing surveyors. Several ways of obtaining 3D data exist namely, traditional surveying, terrestrial laser scanning and from Computer Aided Design (CAD) sources. Various data sources have different data structure and a generalized data structure for 3D cadastre hardly reported. A simple and rapid method for indoor data acquisition is proposed. This seeks to determine if the dual half edge data structure is suitable for 3D cadastre. The dual half edge data structure is applied within a graphical user interface. The concept for indoor surveying or data acquisition within the LA_SpatialUnit of the Land Administration Domain Model (LADM) is presented and proposed. Results show inconsistency of Trimble LaserAce 1000 for distance below 5 m with wide and narrow angle of measurement in indoor environment.

Rapid Modelling of Complex Building Interiors

Great progress has been made on building exterior modelling in recent years, largely driven by the availability of laser scanning techniques. However, the complementary modelling of building interiors has been handicapped both by the limited availability of data and by the limited analytic ability of available 3D data structures. Earlier papers of ours have discussed our progress in developing an appropriate data structure: this paper reports our final results, and demonstrates their feasibility with the modelling of two complex, linked buildings at the University of Glamorgan.