Consistent Density Scanning and Information Extraction From Point Clouds of Building Interiors

Over the last decade, 3D range scanning systems have improved considerably enabling the designers to capture large and complex domains such as building interiors. The captured point cloud is processed to extract specific Building Information Models, where the main research challenge is to simultaneously handle huge and cohesive point clouds representing multiple objects, occluded features and vast geometric diversity. These domain characteristics increase the data complexities and thus make it difficult to extract accurate information models from the captured point clouds. The research work presented in this thesis improves the information extraction pipeline with the development of novel algorithms for consistent density scanning and information extraction automation for building interiors. A restricted density-based, scan planning methodology computes the number of scans to cover large linear domains while ensuring desired data density and reducing rigorous post-processing of data sets. The research work further develops effective algorithms to transform the captured data into information models in terms of domain features (layouts), meaningful data clusters (segmented data) and specific shape attributes (occluded boundaries) having better practical utility. Initially, a direct point-based simplification and layout extraction algorithm is presented that can handle the cohesive point clouds by adaptive simplification and an accurate layout extraction approach without generating an intermediate model. Further, three information extraction algorithms are presented that transforms point clouds into meaningful clusters. The novelty of these algorithms lies in the fact that they work directly on point clouds by exploiting their inherent characteristic. First a rapid data clustering algorithm is presented to quickly identify objects in the scanned scene using a robust hue, saturation and value (H S V) color model for better scene understanding. A hierarchical clustering algorithm is developed to handle the vast geometric diversity ranging from planar walls to complex freeform objects. The shape adaptive parameters help to segment planar as well as complex interiors whereas combining color and geometry based segmentation criterion improves clustering reliability and identifies unique clusters from geometrically similar regions. Finally, a progressive scan line based, side-ratio constraint algorithm is presented to identify occluded boundary data points by investigating their spatial discontinuity

Triangulation algorithms for generating as-Is floor plans

Precisely capturing context is a fundamental first step in dealing with built environments. Previous research has demonstrated that existing methods for generating as-is floor plans of non-orthogonal rooms by non-expert users do not produce geometrically accurate results. The present paper proposes the adaptation of empirical triangulation methods, traditionally used by architects and other building professionals in surveying building interiors, to the development of semi-automated workflow of room survey. A set of triangulation algorithms that automate the plan drawing stage are presented.info:eu-repo/semantics/acceptedVersio

REDISCOVERING CULTURAL HERITAGE SITES BY INTERACTIVE 3D EXPLORATION: A PRACTICAL REVIEW OF OPEN-SOURCE WEBGL TOOLS

Georeferenced reconstructions can help understand the dynamic evolution of the urban context surrounding a historical site, supporting decision-making processes in the field of urban planning. The development of web applications that allow the interaction between 2D and 3D products, as well as their exploration, can facilitate virtual inspections and foster collaboration in digitization of interventions and site evolutions over time. The article discusses how virtual scene reconstructions and visits can provide alternatives to traditional in-situ tourism promotion, through digital storytelling solutions for the exploration of sites. The article also describes how 3D storytelling technologies are currently being used for dissemination cultural heritage sites. The case study of the Castello Farnese, an old XVI century heritage site in Piacenza (Italy), test the adoption of two distinct free and open-source JavaScript WebGL, Potree and Cesium, for the rendering of photogrammetric and laser scanning georeferenced scaled products and for the integration of narrative features such as annotations, camera animations, texts, and other multimedia contents. Potentials and limitations of both tools are discussed in detail, highlighting how they can be implemented for enhancing user experience in virtual tour and exploration of 3D products. In order to guarantee replicability for other case studies, source code of the implemented application is shared on GitHub along with its documentation for contributions

Open reWall: Survey-to-production workflow for building renovation

A reabilitação de espaços interiores, num contexto de personalização em série, requer uma mudança na forma como os sistemas construtivos são desenhados, construídos e reutilizados. Recorrendo a plataformas digitais para a participação os arquitetos, em colaboração com outros atores na indústria AEC, podem desenvolver e oferecer soluções personalizadas e desmontáveis a utilizadores genéricos. Esta investigação propõe o uso de sistemas de construção personalizada em série (CPS) para fornecer sistemas de divisórias desmontáveis fabricadas digitalmente usando metodologias do levantamento à produção ligadas a configuradores online, em que os utilizadores co-projetam soluções para a reabilitação de espaços interiores. A metodologia de investigação socorre-se de pesquisa e análise teórica para definir critérios e objetivos a serem explorados em resolução de problemas de projeto. A partir destas experiências são sintetizados princípios e uma metodologia para a conceção de sistemas CPS de sistemas de divisórias personalizáveis e desmontáveis para a reabilitação. A metodologia clarifica os papeis dos atores, passos, e arquitetura do sistema para implementar um sistema CPS do levantamento à produção. A investigação demonstra que a metodologia de levantamento proposta é utilizável por utilizadores especialistas e não-especialistas, com os últimos a apresentarem em média melhores resultados, e que estes levantamentos têm precisão suficiente para processos do desenho à produção. Também se demonstra que a metodologia do levantamento à produção, a gramática genérica, e os critérios são úteis para os arquitetos conceberem sistemas de divisórias desmontáveis e personalizáveis para sistemas CPS abertos.Building renovation of interior spaces, in the context of mass customization, requires a shift in how construction systems are designed, built, and reused. Leveraging digital frameworks for user participation, architects in collaboration with other stakeholders in the AEC industry may design anddeliver customized and disassemble-able solutions to generic end-users. The research proposes mass customization construction (MCC) systems can deliver cost-effective digitally fabricated and disassemble-able construction systems using survey-to-production workflows deployed in web configurators for end-users to co-design solutions in building renovation. The research methodology uses theoretical inquiry and analysis to define criteria and objectives to be explored in design problem solving. From these experiments generalizable principles and a lowkey workflow for the design of MCC systems of customizable and disassemble-able partition wall construction systems for open building renovation are synthetized. The workflow clarifies stakeholder roles, steps, and system architecture to implement an MCC system from survey to production. This investigation demonstrates the proposed survey workflow is usable by non-expert and expert instance-designers, with the former having on-average better results, and that these can survey spaces with sufficient precision for design-to-production workflows. It is also shown the survey-to-production workflow, the generic grammar, and criteria are useful for architects to design customizable and disassemble-able partition wall systems for open MCC systems

Digital Documentation and Reconstruction of an Ancient Maya Temple and Prototype of Internet GIS Database of Maya Architectur

This is a request for Level II Start-Up funding for an international project to develop and test a working prototype for a new platform for an online, searchable database that can bring together GIS maps, 3D models, and virtual environments for teaching and research. (The planning phase was funded by a Level I Start-Up Grant in 2009.) The prototype will employ existing digital collections on Maya architecture at the UNESCO World Heritage Site of Copan, Honduras and a highly-accurate, hybrid 3D model being developed by the project that will test and demonstrate the platform???s capabilities. Art historians and archaeologists from the University of New Mexico (UNM) and the Honduran Institute of Anthropology and History will work with computer experts from ETH Zurich, FBK Trento, and the University of California to design this online tool

Cell shape analysis of random tessellations based on Minkowski tensors

To which degree are shape indices of individual cells of a tessellation characteristic for the stochastic process that generates them? Within the context of stochastic geometry and the physics of disordered materials, this corresponds to the question of relationships between different stochastic models. In the context of image analysis of synthetic and biological materials, this question is central to the problem of inferring information about formation processes from spatial measurements of resulting random structures. We address this question by a theory-based simulation study of shape indices derived from Minkowski tensors for a variety of tessellation models. We focus on the relationship between two indices: an isoperimetric ratio of the empirical averages of cell volume and area and the cell elongation quantified by eigenvalue ratios of interfacial Minkowski tensors. Simulation data for these quantities, as well as for distributions thereof and for correlations of cell shape and volume, are presented for Voronoi mosaics of the Poisson point process, determinantal and permanental point processes, and Gibbs hard-core and random sequential absorption processes as well as for Laguerre tessellations of polydisperse spheres and STIT- and Poisson hyperplane tessellations. These data are complemented by mechanically stable crystalline sphere and disordered ellipsoid packings and area-minimising foam models. We find that shape indices of individual cells are not sufficient to unambiguously identify the generating process even amongst this limited set of processes. However, we identify significant differences of the shape indices between many of these tessellation models. Given a realization of a tessellation, these shape indices can narrow the choice of possible generating processes, providing a powerful tool which can be further strengthened by density-resolved volume-shape correlations.Comment: Chapter of the forthcoming book "Tensor Valuations and their Applications in Stochastic Geometry and Imaging" in Lecture Notes in Mathematics edited by Markus Kiderlen and Eva B. Vedel Jense