University of Trás-os-Montes e Alto Douro Albert EinsteinTo my family and friends To my soulmate Dércia vii UNIVERSITY OF TRÁS-OS-MONTES E ALTO DOURO PhD in Computer ScienceThe members of the jury recommend to the University of Trás-os-Montes e Alto Douro the acceptance of the thesis entitled "Ontology-based Procedural Modelling of Traversable Buildings Composed by Arbitrary Shapes"accomplished by Telmo Miguel Oliveira Adão in partial fulfillment of the requirements for the degree of Doctor Philosophy. December 2015Jury President:Professor Abstract -3D virtual models of buildings are commonly used in areas such as architecture and video games to preview a house project and to populate a virtual scenario, respectively. Traditionally, the production of these models requires highly skilled manpower and a considerable amount of time. To address this issue, many researchers have developed semi-automatic techniques to produce virtual models expeditiously. These procedural techniques provide different ways of generating buildings, including interiors and outer facades, to serve several purposes (e.g., content generation for video games or archaeological reconstruction). However, the existing techniques focusing on building interiors usually only support the generation of floor plans constrained by regular shapes or contour polygons obtained from rectangles sets. At the same time, the possibility of modelling interior rooms through the specification of its constraint walls remains poorly explored. Moreover, most of the existing procedural generation solutions are guided by complex grammars concerned with geometrical aspects or semantic structures that fit specific project requirements, apparently disregarding the established standards for virtual urban environments, specifically, CityGML.To overcome the noted issues, a novel procedural modelling methodology is proposed in this thesis, one that produces virtual models of buildings, including exteriors outlined by arbitrary shapes and interiors formed by convex polygons. Methodology's regulation is provided by a building ontology -a CityGML-based knowledge structure, planned to be extensible to specific architecture styles -through several guiding data structures such as structured XML and ontology-based grammar. Regarding the supporting process, a treemap approach is used to subdivide the building layout into floor plan areas. During the development of this work, several improvements were progressively made to the treemap in order to enable the subdivision of different constraint polygon types which range from rectangles to arbitrary shapes. Moreover, in the most mature work stage, a method concerning inner room walls adaptation is addressed. Next, a set of operations is performed, from the marking transitions step to the extrusion process that provides the 3D aspect. In addition, an experimental stochastic approach is proposed to automate the production of random buildings using this procedural modelling methodology.A set of tests was made to demonstrate the capabilitie...