453 research outputs found
Conceptual design framework for information visualization to support multidimensional datasets in higher education institutions
Information Visualization (InfoVis) enjoys diverse adoption and applicability because of its strength in solving the problem of information overload inherent in institutional data. Policy and decision makers of higher education institutions (HEIs)
are also experiencing information overload while interacting with studentsâ data, because of its multidimensionality. This constraints decision making processes, and therefore requires a domain-specific InfoVis conceptual design framework which
will birth the domainâs InfoVis tool. This study therefore aims to design HEI Studentsâ data-focused InfoVis (HSDI) conceptual design framework which
addresses the content delivery techniques and the systematic processes in actualizing the domain specific InfoVis. The study involved four phases: 1) a usersâ study to investigate, elicit and prioritize the studentsâ data-related explicit knowledge preferences of HEI domain policy. The corresponding studentsâ data dimensions are then categorised, 2) exploratory study through content analysis of InfoVis design literatures, and subsequent mapping with findings from the usersâ study, to propose the appropriate visualization, interaction and distortion techniques for delivering the domainâs explicit knowledge preferences, 3) conceptual development of the design framework which integrates the techniquesâ model with its design processâas identified from adaptation of software engineering and InfoVis design models, 4) evaluation of the proposed framework through expert review, prototyping, heuristics evaluation, and usersâ experience evaluation. For an InfoVis that will appropriately
present and represent the domain explicit knowledge preferences, support the studentsâ data multidimensionality and the decision making processes, the study found that: 1) mouse-on, mouse-on-click, mouse on-drag, drop down menu, push
button, check boxes, and dynamics cursor hinting are the appropriate interaction techniques,
2) zooming, overview with details, scrolling, and exploration are the appropriate distortion techniques, and 3) line chart, scatter plot, map view, bar chart and pie chart are the appropriate visualization techniques. The theoretical support to the proposed framework suggests that dictates of preattentive processing theory, cognitive-fit theory, and normative and descriptive theories must be followed for InfoVis to aid perception, cognition and decision making respectively. This study contributes to the area of InfoVis, data-driven decision making process, and HEI studentsâ data usage process
Morphing arquitectĂłnico: transformaciones entre las casas usonianas de Frank Lloyd Wright
Esta tesis investiga sobre el proceso de transformación de la forma arquitectónica, analizando una técnica
especĂfica denominada morphing. La tĂ©cnica del morphing se utiliza en los grĂĄficos por ordenador para la
transformación de la forma entre dos o mås objetos dados. Desde un punto de vista técnico, se revisan y
actualizan las metodologĂas y aplicaciones existentes, sus caracterĂsticas especĂficas y sus incidencias sobre
la arquitectura. Desde un punto de vista prĂĄctico, se utilizan una serie de modelos de las casas Usonianas de
Frank Lloyd Wright, con el fin de experimentar la técnica y ver qué utilidades se pueden obtener a partir de su
lĂłgica de diseño. Como resultado de este anĂĄlisis se obtiene una metodologĂa genĂ©rica para el procedimiento
de un morphing arquitectĂłnico.This thesis investigates the transformation of architectural form, analyzing a specific technique called morphing.
Morphing is a technique used in computer graphics to transform a form between two or more given objects.
From a technical point of view, the existing techniques are reviewed and updated, as well as their specific
characteristics and impact on architecture. From a practical point of view, some models of Usonian houses of
Frank Lloyd Wright are used to experience the technique and see which utilities are available from his design
logic. As a result of this analysis a generic methodology for the process of architectural morphing is obtained.Postprint (published version
Realistic simulation and animation of clouds using SkewT-LogP diagrams
Nuvens e clima sĂŁo tĂłpicos importantes em computação grĂĄfica, nomeadamente na simulação e animação de fenĂłmenos naturais. Tal deve-se ao facto de a simulação de fenĂłmenos naturaisâonde as nuvens estĂŁo incluĂdasâencontrar aplicaçÔes em filmes, jogos e simuladores de voo. Contudo, as tĂ©cnicas existentes em computação grĂĄfica apenas permitem representaçÔes de nuvens simplificadas, tornadas possĂveis atravĂ©s de dinĂąmicas fictĂcias que imitam a realidade. O problema que este trabalho pretende abordar prende-se com a simulação de nuvens adequadas para utilização em ambientes virtuais, isto Ă©, nuvens com dinĂąmica baseada em fĂsica que variam ao longo do tempo.
Em meteorologia Ă© comum usar tĂ©cnicas de simulação de nuvens baseadas em leis da fĂsica, contudoossistemasatmosfĂ©ricosdeprediçãonumĂ©ricasĂŁocomputacionalmente pesados e normalmente possuem maior precisĂŁo numĂ©rica do que o necessĂĄrio em computação grĂĄfica. Neste campo, torna-se necessĂĄrio direcionar e ajustar as caracterĂsticas fĂsicas ou contornar a realidade de modo a atingir os objetivos artĂsticos, sendo um fator fundamental que faz com que a computação grĂĄfica se distinga das ciĂȘncias fĂsicas. Contudo, simulaçÔes puramente baseadas em fĂsica geram soluçÔes de acordo com regras predefinidas e tornam-se notoriamente difĂceis de controlar.
De modo a enfrentar esses desafios desenvolvemos um novo mĂ©todo de simulação de nuvens baseado em fĂsica que possui a caracterĂstica de ser computacionalmente leve e simula as propriedades dinĂąmicas relacionadas com a formação de nuvens. Este novo modelo evita resolver as equaçÔes fĂsicas, ao apresentar uma solução explĂcita para essas equaçÔes atravĂ©s de diagramas termodinĂąmicos SkewT/LogP. O sistema incorpora dados reais de forma a simular os parĂąmetros necessĂĄrios para a formação de nuvens. Ă especialmente adequado para a simulação de nuvens cumulus que se formam devido ao um processo convectivo. Esta abordagem permite nĂŁo sĂł reduzir os custos computacionais de mĂ©todos baseados em fĂsica, mas tambĂ©m fornece a possibilidade de controlar a forma e dinĂąmica de nuvens atravĂ©s do controlo dos nĂveis atmosfĂ©ricos existentes no diagrama SkewT/LogP.
Nestatese,abordĂĄmostambĂ©mumoutrodesafio,queestĂĄrelacionadocomasimulação de nuvens orogrĂĄficas. Do nosso conhecimento, esta Ă© a primeira tentativa de simular a formação deste tipo de nuvens. A novidade deste mĂ©todo reside no fato de este tipo de nuvens serem nĂŁo convectivas, oque se traduz nocĂĄlculodeoutrosnĂveis atmosfĂ©ricos. AlĂ©m disso, atendendo a que este tipo de nuvens se forma sobre montanhas, Ă© tambĂ©m apresentadoumalgoritmoparadeterminarainfluĂȘnciadamontanhasobreomovimento da nuvem.
Em resumo, esta dissertação apresenta um conjunto de algoritmos para a modelação e simulação de nuvens cumulus e orogrĂĄficas, recorrendo a diagramas termodinĂąmicos SkewT/LogP pela primeira vez no campo da computação grĂĄfica.Clouds and weather are important topics in computer graphics, in particular in the simulation and animation of natural phenomena. This is so because simulation of natural phenomenaâwhere clouds are includedâfind applications in movies, games and flight simulators. However, existing techniques in computer graphics only offer the simplified cloud representations, possibly with fake dynamics that mimic the reality. The problem that this work addresses is how to find realistic simulation of cloud formation and evolution, that are suitable for virtual environments, i.e., clouds with physically-based dynamics over time.
It happens that techniques for cloud simulation are available within the area of meteorology, but numerical weather prediction systems based on physics laws are computationally expensive and provide more numerical accuracy than the required accuracy in computer graphics. In computer graphics, we often need to direct and adjust physical features, or even to bend the reality, to meet artistic goals, which is a key factor that makes computer graphics distinct from physical sciences. However, pure physically-based simulations evolve their solutions according to pre-set physics rules that are notoriously difficult to control.
In order to face these challenges we have developed a new lightweight physically-based cloudsimulationschemethatsimulatesthedynamicpropertiesofcloudformation. This new model avoids solving the physically-based equations typically used to simulate the formation of clouds by explicitly solving these equations using SkewT/LogP thermodynamic diagrams. The system incorporates a weather model that uses real data to simulate parameters related to cloud formation. This is specially suitable to the simulation of cumulus clouds, which result from a convective process. This approach not only reduces the computational costs of previous physically-based methods, but also provides a technique to control the shape and dynamics of clouds by handling the cloud levels in SkewT/LogP diagrams.
In this thesis, we have also tackled a new challenge, which is related to the simulation oforographic clouds. From ourknowledge, this isthefirstattempttosimulatethis type of cloud formation. The novelty in this method relates to the fact that these clouds are non-convective, so that different atmospheric levels have to be determined. Moreover, since orographic clouds form over mountains, we have also to determine the mountain influence in the cloud motion.
In summary, this thesis presents a set of algorithms for the modelling and simulation of cumulus and orographic clouds, taking advantage of the SkewT/LogP diagrams for the first time in the field of computer graphics
Enhancing Mesh Deformation Realism: Dynamic Mesostructure Detailing and Procedural Microstructure Synthesis
Propomos uma solução para gerar dados de mapas de relevo dinĂąmicos para simular deformaçÔes em superfĂcies macias, com foco na pele humana. A solução incorpora a simulação de rugas ao nĂvel mesoestrutural e utiliza texturas procedurais para adicionar detalhes de microestrutura estĂĄticos. Oferece flexibilidade alĂ©m da pele humana, permitindo a geração de padrĂ”es que imitam deformaçÔes em outros materiais macios, como couro, durante a animação.
As soluçÔes existentes para simular rugas e pistas de deformação frequentemente dependem de hardware especializado, que Ă© dispendioso e de difĂcil acesso. AlĂ©m disso, depender exclusivamente de dados capturados limita a direção artĂstica e dificulta a adaptação a mudanças. Em contraste, a solução proposta permite a sĂntese dinĂąmica de texturas que se adaptam Ă s deformaçÔes subjacentes da malha de forma fisicamente plausĂvel.
Vårios métodos foram explorados para sintetizar rugas diretamente na geometria, mas sofrem de limitaçÔes como auto-interseçÔes e maiores requisitos de armazenamento. A intervenção manual de artistas na criação de mapas de rugas e mapas de tensão permite controle, mas pode ser limitada em deformaçÔes complexas ou onde maior realismo seja necessårio.
O nosso trabalho destaca o potencial dos métodos procedimentais para aprimorar a geração de padrÔes de deformação dinùmica, incluindo rugas, com maior controle criativo e sem depender de dados capturados. A incorporação de padrÔes procedimentais eståticos melhora o realismo, e a abordagem pode ser estendida além da pele para outros materiais macios.We propose a solution for generating dynamic heightmap data to simulate deformations for soft surfaces, with a focus on human skin. The solution incorporates mesostructure-level wrinkles and utilizes procedural textures to add static microstructure details. It offers flexibility beyond human skin, enabling the generation of patterns mimicking deformations in other soft materials, such as leater, during animation.
Existing solutions for simulating wrinkles and deformation cues often rely on specialized hardware, which is costly and not easily accessible. Moreover, relying solely on captured data limits artistic direction and hinders adaptability to changes. In contrast, our proposed solution provides dynamic texture synthesis that adapts to underlying mesh deformations.
Various methods have been explored to synthesize wrinkles directly to the geometry, but they suffer from limitations such as self-intersections and increased storage requirements. Manual intervention by artists using wrinkle maps and tension maps provides control but may be limited to the physics-based simulations.
Our research presents the potential of procedural methods to enhance the generation of dynamic deformation patterns, including wrinkles, with greater creative control and without reliance on captured data. Incorporating static procedural patterns improves realism, and the approach can be extended to other soft-materials beyond skin
Sparse Volumetric Deformation
Volume rendering is becoming increasingly popular as applications require realistic solid shape representations with seamless texture mapping and accurate filtering. However rendering sparse volumetric data is difficult because of the limited memory and processing capabilities of current hardware. To address these limitations, the volumetric information can be stored at progressive resolutions in the hierarchical branches of a tree structure, and sampled according to the region of interest. This means that only a partial region of the full dataset is processed, and therefore massive volumetric scenes can be rendered efficiently.
The problem with this approach is that it currently only supports static scenes. This is because it is difficult to accurately deform massive amounts of volume elements and reconstruct the scene hierarchy in real-time. Another problem is that deformation operations distort the shape where more than one volume element tries to occupy the same location, and similarly gaps occur where deformation stretches the elements further than one discrete location. It is also challenging to efficiently support sophisticated deformations at hierarchical resolutions, such as character skinning or physically based animation. These types of deformation are expensive and require a control structure (for example a cage or skeleton) that maps to a set of features to accelerate the deformation process. The problems with this technique are that the varying volume hierarchy reflects different feature sizes, and manipulating the features at the original resolution is too expensive; therefore the control structure must also hierarchically capture features according to the varying volumetric resolution.
This thesis investigates the area of deforming and rendering massive amounts of dynamic volumetric content. The proposed approach efficiently deforms hierarchical volume elements without introducing artifacts and supports both ray casting and rasterization renderers. This enables light transport to be modeled both accurately and efficiently with applications in the fields of real-time rendering and computer animation. Sophisticated volumetric deformation, including character animation, is also supported in real-time. This is achieved by automatically generating a control skeleton which is mapped to the varying feature resolution of the volume hierarchy. The output deformations are demonstrated in massive dynamic volumetric scenes
Slope-space integrals for specular next event estimation
International audienceMonte Carlo light transport simulations often lack robustness in scenes containing specular or near-specular materials. Widely used uni- and bidirectional sampling strategies tend to find light paths involving such materials with insufficient probability, producing unusable images that are contaminated by significant variance.This article addresses the problem of sampling a light path connecting two given scene points via a single specular reflection or refraction, extending the range of scenes that can be robustly handled by unbiased path sampling techniques. Our technique enables efficient rendering of challenging transport phenomena caused by such paths, such as underwater caustics or caustics involving glossy metallic objects.We derive analytic expressions that predict the total radiance due to a single reflective or refractive triangle with a microfacet BSDF and we show that this reduces to the well known Lambert boundary integral for irradiance. We subsequently show how this can be leveraged to efficiently sample connections on meshes comprised of vast numbers of triangles.Our derivation builds on the theory of off-center microfacets and involves integrals in the space of surface slopes.Our approach straightforwardly applies to the related problem of rendering glints with high-resolution normal maps describing specular microstructure. Our formulation alleviates problems raised by singularities in filtering integrals and enables a generalization of previous work to perfectly specular materials. We also extend previous work to the case of GGX distributions and introduce new techniques to improve accuracy and performance
FACING EXPERIENCE: A PAINTERâS CANVAS IN VIRTUAL REALITY
Full version unavailable due to 3rd party copyright restrictions.This research investigates how shifts in perception might be brought about through the development of visual imagery created by the use of virtual environment technology.
Through a discussion of historical uses of immersion in art, this thesis will explore how immersion functions and why immersion has been a goal for artists throughout history. It begins with a discussion of ancient cave drawings and the relevance of Platoâs Allegory of the Cave. Next it examines the biological origins of âmaking special.â The research will discuss how this concept, combined with the ideas of âactionâ and âreaction,â has reinforced the view that art is fundamentally experiential rather than static. The research emphasizes how present-day virtual environment art, in providing a space that engages visitors in computer graphics, expands on previous immersive artistic practices.
The thesis examines the technical context in which the research occurs by briefly describing the use of computer science technologies, the fundamentals of visual arts practices, and the importance of aesthetics in new media and provides a description of my artistic practice. The aim is to investigate how combining these approaches can enhance virtual environments as artworks. The computer science of virtual environments includes both hardware and software programming. The resultant virtual environment experiences are technologically dependent on the types of visual displays being used, including screens and monitors, and their subsequent viewing affordances. Virtual environments fill the field of view and can be experienced with a head mounted display (HMD) or a large screen display. The sense of immersion gained through the experience depends on how tracking devices and related peripheral devices are used to facilitate interaction.
The thesis discusses visual arts practices with a focus on how illusions shift our cognition and perception in the visual modalities. This discussion includes how perceptual thinking is the foundation of art experiences, how analogies are the foundation of cognitive experiences and how the two intertwine in art experiences for virtual environments. An examination of the aesthetic strategies used by artists and new media critics are presented to discuss new media art. This thesis investigates the visual elements used in virtual environments and prescribes strategies for creating art for virtual environments. Methods constituting a unique virtual environment practice that focuses on visual analogies are discussed. The artistic practice that is discussed as the basis for this research also concentrates on experiential moments and shifts in perception and cognition and references Douglas Hofstadter, Rudolf Arnheim and John Dewey.
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Virtual environments provide for experiences in which the imagery generated updates in real time. Following an analysis of existing artwork and critical writing relative to the field, the process of inquiry has required the creation of artworks that involve tracking systems, projection displays, sound work, and an understanding of the importance of the visitor. In practice, the research has shown that the visitor should be seen as an interlocutor, interacting from a first-person perspective with virtual environment events, where avatars or other instrumental intermediaries, such as guns, vehicles, or menu systems, do not to occlude the view. The aesthetic outcomes of this research are the result of combining visual analogies, real time interactive animation, and operatic performance in immersive space.
The environments designed in this research were informed initially by paintings created with imagery generated in a hypnopompic state or during the moments of transitioning from sleeping to waking. The drawings often emphasize emotional moments as caricatures and/or elements of the face as seen from a number of perspectives simultaneously, in the way of some cartoons, primitive artwork or Cubist imagery. In the imagery, the faces indicate situations, emotions and confrontations which can offer moments of humour and reflective exploration. At times, the faces usurp the space and stand in representation as both face and figure. The power of the placement of the caricatures in the paintings become apparent as the imagery stages the expressive moment. The placement of faces sets the scene, establishes relationships and promotes the honesty and emotions that develop over time as the paintings are scrutinized.
The development process of creating virtual environment imagery starts with hand drawn sketches of characters, develops further as paintings on âdigital canvasâ, are built as animated, three-dimensional models and finally incorporated into a virtual environment. The imagery is generated while drawing, typically with paper and pencil, in a stream of consciousness during the hypnopompic state. This method became an aesthetic strategy for producing a snappy straightforward sketch. The sketches are explored further as they are worked up as paintings. During the painting process, the figures become fleshed out and their placement on the page, in essence brings them to life. These characters inhabit a world that I explore even further by building them into three dimensional models and placing them in computer generated virtual environments. The methodology of developing and placing the faces/figures became an operational strategy for building virtual environments. In order to open up the range of art virtual environments, and develop operational strategies for visitorsâ experience, the characters and their facial features are used as navigational strategies, signposts and methods of wayfinding in order to sustain a stream of consciousness type of navigation.
Faces and characters were designed to represent those intimate moments of self-reflection and confrontation that occur daily within ourselves and with others. They sought to reflect moments of wonderment, hurt, curiosity and humour that could subsequently be relinquished for more practical or purposeful endeavours. They were intended to create conditions in which visitors might reflect upon their emotional state,
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enabling their understanding and trust of their personal space, in which decisions are made and the nature of world is determined.
In order to extend the split-second, frozen moment of recognition that a painting affords, the caricatures and their scenes are given new dimensions as they become characters in a performative virtual reality. Emotables, distinct from avatars, are characters confronting visitors in the virtual environment to engage them in an interactive, stream of consciousness, non-linear dialogue.
Visitors are also situated with a role in a virtual world, where they were required to adapt to the language of the environment in order to progress through the dynamics of a drama. The research showed that imagery created in a context of whimsy and fantasy could bring ontological meaning and aesthetic experience into the interactive environment, such that emotables or facially expressive computer graphic characters could be seen as another brushstroke in painting a world of virtual reality
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