Physically based space planning is a means for automating the conceptual design process by applying the physics of motion to space plan elements. This methodology provides for a responsive design process, allowing a designer to easily make decisions whose consequences propagate throughout the design. It combines the speed of automated design methods with the flexibility of manual design methods, while adding a highly interactive quality and a sense of collaboration with the design. The primary assumption is that a digital design tool based on a physics paradigm can facilitate the architectural space planning process. The hypotheses are that Newtonian dynamics can be used 1) to define mechanical metaphors to represent the elements in an architectural space plan, 2) to compute architectural space planning solutions, and 3) to interact with architectural space plans. I show that space plan elements can be represented as physical masses, that design objectives can be represented using mechanical metaphors such as springs, repulsion fields, and screw clamps, that a layout solution can be computed by using these elements in a dynamical simulation, and that the user can interact with that solution by applying forces that are also models of the same mechanical objects. I present a prototype software application that successfully implements this approach. A subjective evaluation of this prototype reveals that it demonstrates a feasible process for producing space plans, and that it can potentially improve the design process because of the quality of the manipulation and the enhanced opportunities for design exploration it provides to the designer. I found that an important characteristic of this approach is that representation, computation, and interaction are all defined using the same paradigm. This contrasts with most approaches to automated space planning, where these three characteristics are usually defined in completely different ways. Also emerging from this work is a new cognitive theory of design titled 'dynamical design imagery,' which proposes that the elements in a designer's mental imagery during the act of design are dynamic in nature and act as a dynamical system, rather than as static images that are modified in a piecewise algorithmic manner.

Simulating virtual objects which can deform or break apart within their environments is now common in state-of-the-art virtual simulations such as video games or surgery simulations. Real-time performance requires a physical model which provides an approximation to the true solution for fast computations but at the same time provides enough believability of the simulation to the user. Recent research in object deformation and fracture has revolved around embedding portions of the simulation for graphical display inside a much simpler physical domain which is invisible to the user. Embedding complex geometry in a simpler domain allows for very complex effects to occur in a much more robust and computationally efficient manner. This thesis explores a novel method to efficiently embed a high-resolution surface mesh inside a coarse tetrahedral physical mesh for the purposes of interactive simulation and display. A technique to display interior regions as solid geometry without explicitly re-meshing the graphical mesh during fracture has been explored and developed. Keeping the graphical mesh static in memory during simulation allows the geometry to be off-loaded to the GPU while shaders can be utilized to only display portions of the geometry which are locally contained within the physical mesh. Recent advances in GPU technology have also been exploited in order to provide an increase in visual fidelity and help achieve the illusion that the virtual object itself is breaking apart in a physically plausible manner.

Creating realistic virtual hair consists of several major areas: creating the geometry, moving the hair strands realistically and rendering the hair. In this thesis, a background survey covering each one of these areas is given. A node-based, procedural hair system is presented, which utilizes the capabilities of modern GPUs. The hair system is implemented as a plugin for Autodesk Maya, and a user interface is developed to allow the user to control the various parameters. A number of nodes are developed to create effects such as clumping, noise and frizz. The proposed system can easily handle a variety of hairstyles, and pre-renders the result in real-time using a local shading model.

This work focuses on the simulation of fluids as they transition between a solid and a liquid state, and as they interact with rigid bodies in a realistic fashion. There is an underlying theme to my work that I did not recognize until I examined my body of research as a whole. The equations of motion that are generally considered appropriate only for liquids or gas can also be used to model solids. Without adding extra constraints, one can model a solid simply as a fluid with a high viscosity. Admittedly, this representation will only get you so far, but this simple representation can create some very nice animations of objects that start as solids, and then melt into liquid over time. Another way to represent solids with the fluid equations is to add extra constraints to the equations. I use this representation in the parts of this work that focus on the two-way coupling of liquids with rigid bodies. The coupling affects both how the liquid moves the rigid bodies, and how the rigid bodies in turn affect the motion of the fluid. There are three components that are needed to allow solids and fluids to interact: a rigid body solver, a fluid solver, and a mechanism for the coupling of the two solvers. The fluid solver used in this work was presented in [8]. This Melting and Flowing solver is a fast and stable system for animating materials that melt, flow, and solidify. Examples of realworld materials that exhibit these phenomena include melting candles, lava flow, the hardening of cement, icicle formation, and limestone deposition. Key to this fluid solver is the idea that we can plausibly simulate such phenomena by simply varying the viscosity inside a standard fluid solver, treating solid and nearly-solid materials as very high viscosity fluids. The computational method modifies the Marker-And-Cell algorithm [99] in order to rapidly simulate fluids with variable and arbitrarily high viscosity. The modifications allow the viscosity of the material to change in space and time according to variation in temperature, water content, or any other spatial variable. This in turn allows different locations in the same continuous material to exhibit states ranging from the absolute rigidity or slight bending of hardened wax to the splashing and sloshing of water. The coupling that ties together the rigid body and fluid solvers was presented in [7], and is known as the Rigid Fluid method. It is a technique for animating the interplay between rigid bodies and viscous incompressible fluid with free surfaces. Distributed Lagrange multipliers are used to ensure two-way coupling that generates realistic motion for both the solid objects and the fluid as they interact with one another. The rigid fluid method is so named because the simulator treats the rigid objects as if they were made of fluid. The rigidity of such an object is maintained by identifying the region of the velocity field that is inside the object and constraining those velocities to be rigid body motion. The rigid fluid method is straightforward to implement, incurs very little computational overhead, and can be added as a bridge between current fluid simulators and rigid body solvers. Many solid objects of different densities (e.g., wood or lead) can be combined in the same animation. The rigid body solver used in this work is the impulse based solver, with shock propagation introduced by Guendelman et al. in [36]. The rigid body solver allows for collisions ranging from completely elastic, where an object can bounce around forever without loss of energy, to completely inelastic where all energy is spent in the collision. Static and dynamic frictional forces are also incorporated. The details of this rigid body solver will not be discussed, but the small changes needed to couple this solver to interact with fluid will be. When simulating fluids, the fluid-air interface (free surface) is an important part of the simulation. In [8], the free surface is modelled by a set of marker particles, and after running a simulation we create detailed polygonal models of the fluid by splatting particles into a volumetric grid and then render these models using ray tracing with sub-surface scattering. In [7], I model the free surface with a particle level set technique [14]. The surface is then rendered by first extracting a triangulated surface from the level set and then ray tracing that surface with the Persistence of Vision Raytracer (http://povray.org).

We present a method for representing seams in clothing animation, and its application in simulation level of detail. Specifically we consider cloth represented as a regular grid of particles connected by spring-dampers, and a seam specified by a closed set of parametric trim curves in the cloth domain. Conventional cloth animation requires the tessellation of seams so that they are handled uniformly by the dynamics process. Our goal is a seam definition which does not constrain the attached clothing panels to be of the same resolution, or even constant resolution, while not being a hindrance to the dynamics process. We also apply our seams to cloth defined on a regular grid, as opposed to the irregular meshes commonly used with seams. The determination of particles interior to the cloth panel can be done using wellknown graphics operations such as scan-conversion. Due to the particle-based nature of the simulation, the dynamics approach combines easily with existing implicit and explicit methods. Finally, because the seams are resolution independent, the particle density per clothing panel can be adjusted as desired. This gives rise to a simple application of the given seams approach illustrating how it may be used for simulation level of detail.

We present methods for incorporating bubbles into a photorealistc fluid simulation. Previous methods of fluid simulation in computer graphics do not include bubbles. Our system automatically creates bubbles, which are simulated on top of the fluid simulation. These bubbles are approximated by spheres and are rendered with the fluid to appear as one continuous surface. This enhances the overall realism of the appearance of a splashing fluid for computer graphics. Our methods leverage the particle level set representation of the fluid surface. We create bubbles from escaped marker particles from the outside to the inside. These marker particles might represent air that has been trapped within the fluid surface. Further, we detect when air is trapped in the fluid and create bubbles within this space. This gives the impression that the air pocket has become bubbles and is an inexpensive way to simulate the air trapped in air pockets. The results of the simulation are rendered with a raytracer that includes caustics. This allows the creation of photorealistic images. These images support our position that the simple addition of bubbles included in a fluid simulation creates results that are much more true to life.

This thesis describes a method for using physically based techniques to model an explosion and the resulting side effects. Explosions are some of the most visually exciting phenomena known to humankind and have become nearly ubiquitous in action films. A realistic computer simulation of this powerful event would be cheaper, quicker, and much less complicated than safely creating the real thing. The immense energy released by a detonation creates a discontinuous localized increase in pressure and temperature. Physicists and engineers have shown that the dissipation of this concentration of energy, which creates all the visible effects, adheres closely to the compressible Navier-Stokes equation. This program models the most noticeable of these results. In order to simulate the pressure and temperature changes in the environment, a three dimensional grid is placed throughout the area around the detonation and a discretized version of the Navier-Stokes equation is applied to the resulting voxels. Objects in the scene are represented as rigid bodies that are animated by the forces created by varying pressure on their hulls. Fireballs, perhaps the most awe-inspiring side effects of an explosion, are simulated using massless particles that flow out from the center of the blast and follow the currents created by the dissipating pressure. The results can then be brought into Maya for evaluation and tweaking.

This thesis presents a method for simulating fluids on a view dependent grid structure to exploit level-of-detail with distance to the viewer. Current computer graphics techniques, such as the Stable Fluid and Particle Level Set methods, are modified to support a nonuniform simulation grid. In addition, infinite fluid boundary conditions are introduced that allow fluid to flow freely into or out of the simulation domain to achieve the effect of large, boundary free bodies of fluid. Finally, a physically based rendering method known as photon mapping is used in conjunction with ray tracing to generate realistic images of water with caustics. These methods were implemented as a C++ application framework capable of simulating and rendering fluid in a variety of user-defined coordinate systems.

Physically based space planning is a means for automating the conceptual design process by applying the physics of motion to space plan elements. This methodology provides for a responsive design process, allowing a designer to easily make decisions whose consequences propagate throughout the design. It combines the speed of automated design methods with the flexibility of manual design methods, while adding a highly interactive quality and a sense of collaboration with the design. The primary assumption is that a digital design tool based on a physics paradigm can facilitate the architectural space planning process. The hypotheses are that Newtonian dynamics can be used 1) to define mechanical metaphors to represent the elements in an architectural space plan, 2) to compute architectural space planning solutions, and 3) to interact with architectural space plans. I show that space plan elements can be represented as physical masses, that design objectives can be represented using mechanical metaphors such as springs, repulsion fields, and screw clamps, that a layout solution can be computed by using these elements in a dynamical simulation, and that the user can interact with that solution by applying forces that are also models of the same mechanical objects. I present a prototype software application that successfully implements this approach. A subjective evaluation of this prototype reveals that it demonstrates a feasible process for producing space plans, and that it can potentially improve the design process because of the quality of the manipulation and the enhanced opportunities for design exploration it provides to the designer. I found that an important characteristic of this approach is that representation, computation, and interaction are all defined using the same paradigm. This contrasts with most approaches to automated space planning, where these three characteristics are usually defined in completely different ways. Also emerging from this work is a new cognitive theory of design titled 'dynamical design imagery,' which proposes that the elements in a designer's mental imagery during the act of design are dynamic in nature and act as a dynamical system, rather than as static images that are modified in a piecewise algorithmic manner.

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Atenciosamente, Biblioteca Campus Rio Claro Repositório Institucional UNESP https://repositorio.unesp.br on 2018-06-26T11:30:12Z (GMT) / Submitted by Victor Carvalho Cabral (victorccb@gmail.com) on 2018-06-26T11:47:58Z No. of bitstreams: 1 Capa.pdf: 125651871 bytes, checksum: e1e77feaf754f31d8dfc98b900c4bea6 (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2018-06-26T17:22:32Z (GMT) No. of bitstreams: 1 cabral_vc_me_rcla.pdf: 125494359 bytes, checksum: cfb536df102b46e911652b61675e96a5 (MD5) / Made available in DSpace on 2018-06-26T17:22:32Z (GMT). No. of bitstreams: 1 cabral_vc_me_rcla.pdf: 125494359 bytes, checksum: cfb536df102b46e911652b61675e96a5 (MD5) Previous issue date: 2018-06-20 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Apesar de consideráveis avanços na análise de impacto e gestão de riscos de movimentos de massa, estes continuam a representar grande risco à vida e infraestruturas em regiões montanhosas no mundo. A região da Serra do Mar, devido à suas características geomorfológicas, climáticas e ao avanço da urbanização, é região favorável à ocorrência de movimentos de massa, sobretudo os escorregamentos translacionais rasos. Embora a previsão de áreas instáveis seja essencial para a redução dos danos que esses processos causam, a tarefa não é simples em função da complexidade e variabilidade de fatores que controlam a estabilidade das encostas. A aplicação de modelos de bases físicas é forma objetiva de caracterização de movimentos de massa, especialmente escorregamentos translacionais, em função da aplicação direta de equações que descrevem fisicamente esses processos erosivos naturais, prevendo a suscetibilidade sob diferentes cenários de uso e ocupação do solo e situações climáticas. Este trabalho tem como objetivo a avaliação da suscetibilidade a escorregamentos translacionais rasos nas bacias hidrográficas dos rio Mogi e Perequê, município de Cubatão (SP), através da caracterização geológica-geotécnica e da aplicação dos modelos de base física SHALSTAB e SINMAP. Ademais, tem como objetivo a determinação do modelo que melhor se aplica à região de estudo nas escalas de trabalho. Através da criação do modelo digital de elevação (MDE) da área de estudo, base para a obtenção das informações topográficas, da coleta de amostras de solo nas campanhas de campo e da realização de ensaios laboratoriais na obtenção dos parâmetros geotécnicos, é feita a modelagem usando os modelos SINMAP e SHALSTAB nas escalas de 1:50.000 e 1:10.000. A calibração dos modelos é baseada no mapeamento de cicatrizes de episódios de escorregamentos que ocorreram na região nos anos de 1994 e 1985, onde, respectivamente, 542 e 1679 cicatrizes foram mapeadas por meio de imagens aéreas na escala de 1:25.000. Utilizando os métodos de taxa de sucesso e erro e matriz de contingência na determinação do modelo que melhor se aplica à área de estudo, o modelo SHALSTAB mostra-se o mais adequado em ambas as escalas de trabalho pois apresenta maior acurácia (cicatrizes dentro de áreas instáveis) e menor proporção de cicatrizes em áreas estáveis (falsos negativos). Portanto, o emprego de modelos de bases físicas na avaliação da suscetibilidade a escorregamentos na Serra do Mar mostra-se eficaz e representa importante auxílio na análise de risco que esses fenômenos podem representar à sociedade. A determinação do modelo que melhor se aplica a uma área específica é essencial na qualidade e eficiência de análises e avaliações de riscos a escorregamentos pois é uma ferramenta direta e objetiva de representação de processos erosivos. / Despite considerable advances on mass movements risk analysis and assessment, these processes still represent great danger to infrastructure and human lives in mountainous regions around the world. The Serra do Mar region, due to its geomorphological and climatic characteristics and due to urbanisation increase, is highly susceptible to mass movements’ occurrences, especially shallow landslides. While the prediction and mapping of unstable areas are essential to mitigate damages that these processes can cause, it is not an easy task due to the complexity and variability of the parameters that control slope stability. The application of physically based models is an objective method to characterise mass movements, especially shallow landslides, since it directly applies equations that physically describe the processes, predicting their susceptibility under many different scenarios of land use and climatic situations. The objective of this dissertation is the application of the SHALSTAB and SINMAP models on shallow landslide susceptibility assessment at the Mogi and Perequê rivers’ watersheds, in the municipality of Cubatão (São Paulo). Also, it aims to determine which model best represents slope stability in the study area at each work scale. Based on the digital elevation model (DEM), which provides topographic information to the model, and soil samples collected during fieldwork that later were tested to acquire geotechnical parameters, the modelling of shallow landslides is made using the SINMAP and SHALSTAB models at the scales of 1:50.000 and 1:10.000. The model calibration is based on landslide scars mapping of mass movements events that occurred in the region in 1994 and 1985, where, respectively, 542 and 1679 landslides scars were mapped using aerial images at a scale of 1:25.000. By using the success and error index method and a contingency table to determine the model that best suits the study region, the SHALSTAB model stands out as the most adequate in both work scales since it presents a higher accuracy (landslide scars within unstable areas) and lower proportion of landslide scars in stable areas (false negatives). The application of physically based models in assessing landslide susceptibility at the Serra do Mar region proves to be successful and, therefore, represents an important tool in risk analysis and assessment. The determination of a model that best represents the slope stability of a particular region is essential to the quality and efficiency of landslide risk analysis and assessment, as well as in urban planning, since it is a direct and objective method of representing and predicting the occurrence of these erosive processes. / CNPq: 134323/2016-5.