Ontology-based Procedural Modelling of Traversable Buildings Composed by Arbitrary Shapes
Telmo Adão, Luís Magalhães, Emanuel Peres
SpringerBriefs in Computer Science
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
... ors 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 capabilities of the proposed methodology xi in producing distinct building formats (buildings constrained by convex and nonconvex shapes, houses with specific room constraint walls) and different architectonic structures (general purpose houses, roman domus) in short time periods. Moreover, the effectiveness of the treemap approach in subdividing random layouts is shown, along with a generic stochastic process for automatic building generation and also some computational performance measurements.