Real-time Physics Based Simulation for 3D Computer Graphics

Restoration of realistic animation is a critical part in the area of computer graphics. The goal of this sort of simulation is to imitate the behavior of the transformation in real life to the greatest extent. Physics-based simulation provides a solid background and proficient theories that can be applied in the simulation. In this dissertation, I will present real-time simulations which are physics-based in the area of terrain deformation and ship oscillations. When ground vehicles navigate on soft terrains such as sand, snow and mud, they often leave distinctive tracks. The realistic simulation of such vehicle-terrain interaction is important for ground based visual simulations and many video games. However, the existing research in terrain deformation has not addressed this issue effectively. In this dissertation, I present a new terrain deformation algorithm for simulating vehicle-terrain interaction in real time. The algorithm is based on the classic terramechanics theories, and calculates terrain deformation according to the vehicle load, velocity, tire size, and soil concentration. As a result, this algorithm can simulate different vehicle tracks on different types of terrains with different vehicle properties. I demonstrate my algorithm by vehicle tracks on soft terrain. In the field of ship oscillation simulation, I propose a new method for simulating ship motions in waves. Although there have been plenty of previous work on physics based fluid-solid simulation, most of these methods are not suitable for real-time applications. In particular, few methods are designed specifically for simulating ship motion in waves. My method is based on physics theories of ship motion, but with necessary simplifications to ensure real-time performance. My results show that this method is well suited to simulate sophisticated ship motions in real time applications

A framework for local terrain deformation based on diffusion theory

Terrains have a key role in making outdoor virtual scenes believable and immersive as they form the support for every other natural element in the scene. Although important, terrains are often given limited interactivity in real-time applications. However, in nature, terrains are dynamic and interact with the rest of the environment changing shape on different levels, from tracks left by a person running on a gravel soil (micro-scale), to avalanches on the side of a mountain (macro-scale). The challenge in representing dynamic terrains correctly is that the soil that forms them is vastly heterogeneous and behaves differently depending on its composition. This heterogeneity introduces difficulties at different levels in dynamic terrains simulations, from modelling the large amount of different elements that compose the oil to simulating their dynamic behaviour. This work presents a novel framework to simulate multi-material dynamic terrains by taking into account the soil composition and its heterogeneity. In the proposed framework soil information is obtained from a material description map applied to the terrain mesh. This information is used to compute deformations in the area of interaction using a novel mathematical model based on diffusion theory. The deformations are applied to the terrain mesh in different ways depending on the distance of the area of interaction from the camera and the soil material. Deformations away from the camera are simulated by dynamically displacing normals. While deformations in a neighbourhood of the camera are represented by displacing the terrain mesh, which is locally tessellated to better fit the displacement. For gravel based soils the terrain details are added near the camera by reconstructing the meshes of the small rocks from the texture image, thus simulating both micro and macro-structure of the terrain. The outcome of the framework is a realistic interactive dynamic terrain animation in real-time

Generation and Rendering of Interactive Ground Vegetation for Real-Time Testing and Validation of Computer Vision Algorithms

During the development process of new algorithms for computer vision applications, testing and evaluation in real outdoor environments is time-consuming and often difficult to realize. Thus, the use of artificial testing environments is a flexible and cost-efficient alternative. As a result, the development of new techniques for simulating natural, dynamic environments is essential for real-time virtual reality applications, which are commonly known as Virtual Testbeds. Since the first basic usage of Virtual Testbeds several years ago, the image quality of virtual environments has almost reached a level close to photorealism even in real-time due to new rendering approaches and increasing processing power of current graphics hardware. Because of that, Virtual Testbeds can recently be applied in application areas like computer vision, that strongly rely on realistic scene representations. The realistic rendering of natural outdoor scenes has become increasingly important in many application areas, but computer simulated scenes often differ considerably from real-world environments, especially regarding interactive ground vegetation. In this article, we introduce a novel ground vegetation rendering approach, that is capable of generating large scenes with realistic appearance and excellent performance. Our approach features wind animation, as well as object-to-grass interaction and delivers realistically appearing grass and shrubs at all distances and from all viewing angles. This greatly improves immersion, as well as acceptance, especially in virtual training applications. Nevertheless, the rendered results also fulfill important requirements for the computer vision aspect, like plausible geometry representation of the vegetation, as well as its consistence during the entire simulation. Feature detection and matching algorithms are applied to our approach in localization scenarios of mobile robots in natural outdoor environments. We will show how the quality of computer vision algorithms is influenced by highly detailed, dynamic environments, like observed in unstructured, real-world outdoor scenes with wind and object-to-vegetation interaction

A Framework for Dynamic Terrain with Application in Off-road Ground Vehicle Simulations

The dissertation develops a framework for the visualization of dynamic terrains for use in interactive real-time 3D systems. Terrain visualization techniques may be classified as either static or dynamic. Static terrain solutions simulate rigid surface types exclusively; whereas dynamic solutions can also represent non-rigid surfaces. Systems that employ a static terrain approach lack realism due to their rigid nature. Disregarding the accurate representation of terrain surface interaction is rationalized because of the inherent difficulties associated with providing runtime dynamism. Nonetheless, dynamic terrain systems are a more correct solution because they allow the terrain database to be modified at run-time for the purpose of deforming the surface. Many established techniques in terrain visualization rely on invalid assumptions and weak computational models that hinder the use of dynamic terrain. Moreover, many existing techniques do not exploit the capabilities offered by current computer hardware. In this research, we present a component framework for terrain visualization that is useful in research, entertainment, and simulation systems. In addition, we present a novel method for deforming the terrain that can be used in real-time, interactive systems. The development of a component framework unifies disparate works under a single architecture. The high-level nature of the framework makes it flexible and adaptable for developing a variety of systems, independent of the static or dynamic nature of the solution. Currently, there are only a handful of documented deformation techniques and, in particular, none make explicit use of graphics hardware. The approach developed by this research offloads extra work to the graphics processing unit; in an effort to alleviate the overhead associated with deforming the terrain. Off-road ground vehicle simulation is used as an application domain to demonstrate the practical nature of the framework and the deformation technique. In order to realistically simulate terrain surface interactivity with the vehicle, the solution balances visual fidelity and speed. Accurately depicting terrain surface interactivity in off-road ground vehicle simulations improves visual realism; thereby, increasing the significance and worth of the application. Systems in academia, government, and commercial institutes can make use of the research findings to achieve the real-time display of interactive terrain surfaces

Mobile three-dimensional city maps

Maps are visual representations of environments and the objects within, depicting their spatial relations. They are mainly used in navigation, where they act as external information sources, supporting observation and decision making processes. Map design, or the art-science of cartography, has led to simplification of the environment, where the naturally three-dimensional environment has been abstracted to a two-dimensional representation, populated with simple geometrical shapes and symbols. However, abstract representation requires a map reading ability. Modern technology has reached the level where maps can be expressed in digital form, having selectable, scalable, browsable and updatable content. Maps may no longer even be limited to two dimensions, nor to an abstract form. When a real world based virtual environment is created, a 3D map is born. Given a realistic representation, would the user no longer need to interpret the map, and be able to navigate in an inherently intuitive manner? To answer this question, one needs a mobile test platform. But can a 3D map, a resource hungry real virtual environment, exist on such resource limited devices? This dissertation approaches the technical challenges posed by mobile 3D maps in a constructive manner, identifying the problems, developing solutions and providing answers by creating a functional system. The case focuses on urban environments. First, optimization methods for rendering large, static 3D city models are researched and a solution provided by combining visibility culling, level-of-detail management and out-of-core rendering, suited for mobile 3D maps. Then, the potential of mobile networking is addressed, developing efficient and scalable methods for progressive content downloading and dynamic entity management. Finally, a 3D navigation interface is developed for mobile devices, and the research validated with measurements and field experiments. It is found that near realistic mobile 3D city maps can exist in current mobile phones, and the rendering rates are excellent in 3D hardware enabled devices. Such 3D maps can also be transferred and rendered on-the-fly sufficiently fast for navigation use over cellular networks. Real world entities such as pedestrians or public transportation can be tracked and presented in a scalable manner. Mobile 3D maps are useful for navigation, but their usability depends highly on interaction methods - the potentially intuitive representation does not imply, for example, faster navigation than with a professional 2D street map. In addition, the physical interface limits the usability

Procedural modelling techniques to configure driving serious game scenes

Esta dissertação tem o objetivo de tratar do problema da segurança rodoviária, a fim de evitar mais acidentes e mortes tanto de motoristas como de pedestres através da criação de uma ferramenta que é capaz de carregar dados do mundo real a partir de localizações selecionadas pelo utilizador e transformá-los em modelos tridimensionais para uso posterior em jogos de condução sérios. Estes modelos são então povoados com os pedestres que andam nos passeios e a capacidade de conduzir um veículo é dada ao utilizador. Além disso, a ferramenta deve ser flexível o suficiente para permitir que os utilizadores configurem diferentes condições, tais como o tempo, hora do dia, opções de renderização, os danos do veículo e densidade de pedestres, a fim de realizar estudos em diferentes condições. O projeto também deve ser de código aberto, para que qualquer pessoa pode editá-lo e expandi-lo para atender as suas necessidades e realizar estudos específicos. Possui integração Oculus Rift, que estende ainda mais a possibilidade de realização de estudos para o motorista humano, através da expanção dessa integração para avaliar os comportamentos do motorista. Outro aspeto importante é a possibilidade de exportar toda a cena procedimentalmente gerada para um formato de ficheiro 3D que pode ser editado numa aplicação externa.Ao fornecer esta ferramenta de forma gratuita, não só marca o início de um gerador do mundo em 3D de código aberto, mas também uma ferramenta capaz de permitir diversos usos diferentes, tais como a realização de estudos, a construção de cenários de jogos de vídeo ou ser usado como uma ferramenta de aprendizagem por uma escola de condução. Esperemos que isto seja capaz de aumentar a segurança rodoviária, se usado com cuidado como uma ferramenta séria.Para fazer isto vamos usar o motor de jogo Unity 5 para desenvolver o projeto, CGIAR-CSI para baixar dados de elevação, o Google Static Maps para as imagens de satélite, OpenStreetMap para os dados de localização e tudo o mais é construído dentro do Unity. Também é usado o UnitySlippyMap, que é um mapa do mundo que trabalha com vários fornecedores de "tiles" que foi integrado no contexto deste projeto para permitir que os utilizadores selecionem um local dentro do Unity.Ao longo deste documento, irá encontrar uma revisão da literatura sobre o tema, incluindo o trabalho relacionado e tentativas de fazer projetos semelhantes, seguido de uma comparação entre outros projetos e este. Irá também encontrar detalhes sobre o desenvolvimento e a arquitetura do sistema, bem como detalhes profundos sobre a implementação. No final pode encontrar algumas capturas de ecrã dos resultados deste projeto e a conclusão que refere a satisfação dos objetivos e trabalho futuro.Palavras Chave: Modelação Procedimental, Simulação de Condução, Locais do Mundo, Jogos Sérios, Segurança RodoviáriaThis dissertation has the objective of tackling the road safety problem in order to further prevent accidents and casualties for both drivers and pedestrians by creating a tool that is capable of loading real world data from user selected locations and render them in 3 dimensional models for further use in serious driving games. These models are then populated with pedestrians that walk around and the ability to drive a vehicle is given to the user. Also the tool should be flexible enough to allow the users to configure the different conditions such as weather, time of day, rendering options, vehicle damage and pedestrian density, in order to conduct studies on different conditions. The project should also be open source, so anyone can edit it and expand it their own way to suit their needs and conduct specific studies. It features Oculus Rift integration, which further extends the possibility of conducting studies to the human driver by giving the possibility to expand this integration to evaluate the driver's behaviours. Another important aspect is the possibility to export the entire procedurally generated scene to a 3D file format that can be edited by an external application.By providing such tool for free, not only marks the beginning of an open source world 3D generator, but also a framework capable of allowing multiple different usages, such as conducting studies, building video game scenarios or be used as a learning tool by a driving school for instance. Hopefully this will increase road safety if used carefully as a serious tool.To do so we'll use the game engine Unity 5 to develop the project, CGIAR-CSI to download elevation data, Google Static Maps for the satellite imagery, OpenStreetMap for the location data and everything else is built inside Unity. Also UnitySlippyMap, which is a world map that works with various tile providers was used and integrated on the context of this project to allow users to select a location inside Unity.Along this document you will find a literature review on the topic, including related work and attempts to do similar projects followed by a comparison between other project and this one. The reader will also find details about development and the system's architecture as well as deep details about implementation. On the end you can find a few screen shots of the results of this project.Key Words: Procedural Modelling, Driving Simulation, World Locations, Serious Games, Road Safet

Modelling and verifying land-use regulations comprising 3D components to detect spatio-semantic conflicts

L'utilisation du territoire est régie par différents mécanismes que nous pourrions nommer géorèglementations comme par exemples les plans d'urbanisme, les permis de construire ou le zonage. La géorèglementation, en anglais, on parle de Land-use Regulation (LuR), permet d'imposer ou d'influencer l'utilisation d'un territoire dans le but d'atteindre des objectifs de politique publique. Qu'on le veule ou pas, la géorèglementation est nécessaire car elle permet de consolider une saine gestion des ressources, elle aide à la conservation et au développement du territoire, elle fournit un cadre législatif important pour assurer la sécurité et le bon fonctionnement pour l'accès et l'utilisation harmonieuse du territoire. La géorèglementation s'applique donc sur un territoire, où les composantes spatiales, comme la géométrie des éléments, sont primordiales. Il faudra par exemple tenir compte des marges de recul (donc distance) lors de la construction d'une maison, d'une superficie maximale de construction, etc. Ces composantes spatiales du territoire et son occupation peuvent également faire intervenir la 3e dimension comme la profondeur, la hauteur ou encore le volume. La pratique et la littérature montrent que la géorèglementation est actuellement principalement décrite dans des documents de planification et des lignes directrices, dont certains peuvent inclure une représentation spatiale en 2D (i.e. des cartes). On retrouve parfois de coupes transversales en 2D pour représenter l'étendue 2D/3D des LuRs. Cette manière de travailler à partir de document manuscrit et de plans 2D présente des lacunes importantes. Elle limite la possibilité d'avoir une compréhension complète et adéquate de l'étendue 3D des LuRs et donc dans la prise de décision, comme par exemple, la détection de conflits potentiels dans la délivrance de permis de construire ou d'aménagement. De plus, l'application et donc la validation de ces géorèglementations à partir de documents descriptifs prend du temps et laisse place à la subjectivité, ce qui peut conduire à de mauvaises décisions. Les autorités en matière de planification territoriale devraient avoir accès à toutes les informations et à toutes les représentations spatiales requises pour évaluer les LuRs et détecter les conflits potentiels. Force est de constater, que ce n'est pas le cas actuellement, et que même si des modèles 3D de bâtiments (BIM) ou de ville (CityGML) ont vu le jour, ils ne sont pas intégrés dans ces processus de géorèglementation. Cette recherche doctorale est dédiée à la conception et au développement d'un cadre de référence pour la modélisation géométrique 3D des LuRs, leur intégration dans le contexte des modèles de ville 3D et la détection automatique des conflits spatio-sémantiques potentiels lors de la validation des LuRs. Ce cadre de référence vise donc à soutenir les autorités en matière d'application de géorèglementations. La recherche se décline en cinq sous-objectifs soit 1) proposer un inventaire des différents LuRs 3D en précisant leurs composantes 3D/verticales, 2) proposer une classification fonctionnelle basée sur l'ampleur des conflits potentiels des LuRs 3D pour soutenir la prise de décision des autorités, 3) modéliser les LuRs en 3D puis les combiner avec d'autres sources d'information (ex. BIM, CityGML et cartes de zonage), 4) détecter les conflits spatiaux et sémantiques potentiels qui pourraient survenir entre les LuRs modélisés et les objets physiques comme les éléments de construction et, 5) concevoir et développer une preuve de faisabilité. Parmi plus de 100 de géorèglementations 2D/3D passés en revue, 18 de géorèglementations 3D sont inventoriées et discutées en profondeur. Par la suite, pour chacune de ces géorèglementations, les informations et paramètres requis pour leur modélisation 3D automatique sont établis. L'approche proposée permet l'intégration de la modélisation 3D de ces géorèglementations à des modèles de villes et de bâtiments 3D (par exemple, BIM, CityGML et le zonage). Enfin, la thèse fournie un cadre procédurale pour vérifier automatiquement si les géorèglementations 3D viennent en conflit avec des éléments de bâtis planifiés. La preuve de faisabilité est un prototype Web basée sur une étude de cas axée sur le processus d'émission de permis de construire d'un bâtiment situé dans la ville de Melbourne, Victoria, Australie. Les géorèglementations 3D suivantes ont été modélisées et vérifiées : 1) limites de construction en hauteur, 2) exposition au soleil pour estimer l'efficacité énergétique du bâtiment, 3) limite des zones d'ombrage, 4) limites de l'impact sonore, 5) zonage de vue, 6) marges latérales et arrières, 7) marges de rue (côtés et frontaux), et 8) limites d'inondation.The use and developments of land are regulated by utilising different mechanisms called Land-use Regulation (LuR) in various forms such as planning activities, zoning codes, permit requirements, or subdivision controls of cities. LuR makes it possible to impose or influence the use and development of land in order to achieve public policy objectives. Indeed, LuR is essential since it allows the appropriate reinforcement of resource management, contributes to the land protection and development, and provides a tangible legal framework to ensure safety and proper functioning for the harmonious access and use of land. LuRs applies to land, where the spatial components, such as the geometry of the elements, are essential. For example, setback and height limits (i.e., the distance) or different floors' gross area should be considered when owners/developers propose a new construction on their property. These spatial components of the land, its occupied elements (e.g., building elements), or LuR itself can comprise the third dimension (i.e., depth, height, or even volume). Literature and related works show that LuR is currently mainly described in planning documents and guidelines, some of which may include 2D spatial representation (i.e., maps) or 2D cross-sections to represent the LuRs' 2D/3D extent. This method (i.e., working on textual documents and 2D plans) has significant shortcomings in understanding the LuRs' 3D extent and in decision-making (e.g., detecting potential conflicts in issuing planning/building permits). Moreover, checking LuRs' descriptions inside the textual documents is time-consuming, and subjective which might lead to erroneous decisions. Planning authorities need to have access to all information and the spatial representation that is required to assess LuRs and detect their potential conflicts. Clearly, it is generally lacking and even if 3D models of buildings (e.g., BIM designs) or cities (e.g., CityGML) have emerged, they do not incorporate the concept of LuRs. This Ph.D. research follows qualitative engineering type of method that generally aims to propose a conceptual framework for modelling 3D LuRs geometrically as part of 3D city models and formalising geometric and semantic requirements for detecting LuRs' potential conflicts automatically to support planning authorities in the statuary planning phase. To achieve the general objective, five specific objectives are defined as: 1) to formulate an inventory of various 3D LuRs specifying their 3D/vertical components, 2) to propose a functional classification based on the magnitude of 3D LuRs' potential conflicts for supporting planning authorities' decision-making goals, 3) to model LuRs in 3D and then combine them with other sources of information (e.g., BIM, city models, and zoning maps), 4) to automate the detection of potential spatio-semantic conflicts that might arise between the modelled LuRs and physical objects like building elements, and 5) to design and develop proof of feasibility for modelling and verifying 3D LuRs automatically. Among more than one hundred 2D/3D reviewed LuRs, eighteen 3D LuRs are inventoried and discussed thoroughly. For each of these LuRs, the research work identifies and proposes the required information (as level of information need) by considering both geometries and semantics to combine modelled LuRs with other sources of information (e.g., BIM, CityGML, and planning maps). Finally, the thesis proposes the level of information need considering requirements to verify 3D LuRs automatically for detecting potential conflicts using analytical rules (e.g., clash detection). The proof of feasibility is a web-based prototype based on a case study located in the City of Melbourne (where planning activities are under the control of authorities in the state of Victoria, Australia) focusing on the planning permit process. The following 3D LuRs were modelled and verified: 1) building height limits, 2) energy efficiency protection, 3) overshadowing open space, 4) noise impacts, 5) overlooking, 6) side and rear setbacks, 7) street setbacks (side and front), and 8) flooding limits

Aeronautical Engineering: A special bibliography with indexes, supplement 62

This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1975

Proceedings. 9th 3DGeoInfo Conference 2014, [11-13 November 2014, Dubai]

It is known that, scientific disciplines such as geology, geophysics, and reservoir exploration intrinsically use 3D geo-information in their models and simulations. However, 3D geo-information is also urgently needed in many traditional 2D planning areas such as civil engineering, city and infrastructure modeling, architecture, environmental planning etc. Altogether, 3DGeoInfo is an emerging technology that will greatly influence the market within the next few decades. The 9th International 3DGeoInfo Conference aims at bringing together international state-of-the-art researchers and practitioners facilitating the dialogue on emerging topics in the field of 3D geo-information. The conference in Dubai offers an interdisciplinary forum of sub- and above-surface 3D geo-information researchers and practitioners dealing with data acquisition, modeling, management, maintenance, visualization, and analysis of 3D geo-information