Kider, Joseph T
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Publication Simulation of 3D Model, Shape, and Appearance Aging by Physical, Chemical, Biological, Environmental, and Weathering Effects(2012-01-01) Kider, Joseph T.Physical, chemical, biological, environmental, and weathering effects produce a range of 3D model, shape, and appearance changes. Time introduces an assortment of aging, weathering, and decay processes such as dust, mold, patina, and fractures. These time-varying imperfections provide the viewer with important visual cues for realism and age. Existing approaches that create realistic aging effects still require an excessive amount of time and effort by extremely skilled artists to tediously hand fashion blemishes or simulate simple procedural rules. Most techniques do not scale well to large virtual environments. These limitations have prevented widespread utilization of many aging and weathering algorithms. We introduce a novel method for geometrically and visually simulating these processes in order to create visually realistic scenes. This work proposes the ``mu-ton" system, a framework for scattering numerous mu-ton particles throughout an environment to mutate and age the world. We take a point based representation to discretize both the decay effects and the underlying geometry. The mu-ton particles simulate interactions between multiple phenomena. This mutation process changes both the physical properties of the external surface layer and the internal volume substrate. The mutation may add or subtract imperfections into the environment as objects age. First we review related work in aging and weathering, and illustrate the limitations of the current data-driven and physically based approaches. We provide a taxonomy of aging processes. We then describe the structure for our ``mu-ton" framework, and we provide the user a short tutorial how to setup different effects. The first application of the ``mu-ton" system focuses on inorganic aging and decay. We demonstrate changing material properties on a variety of objects, and simulate their transformation. We show the application of our system aging a simple city alley on different materials. The second application of the ``mu-ton" system focuses organic aging. We provide details on simulating a variety of growth processes. We then evaluate and analyze the ``mu-ton" framework and compare our results with ``gamma-ton" tracing. Finally, we outline the contributions this thesis provides to computer-based aging and weathering simulation.Publication Real-Time Evacuation Simulation in Mine Interior Model of Smoke and Action(2010-01-01) Huang, Pengfei; Kider, Joseph T; Sunshine-Hill, Ben; McCaffrey, Jonathan B.; Rios, Desiree Velazquez; Badler, Norman I; Kang, JinshengVirtual human crowd models have been used in the simulation of building and urban evacuation, but have not yet applied to underground coal mine operations and escape situations with emphasis on smoke, fires and physiological behaviors. We explore this through a real-time simulation model, MIMOSA (Mine Interior Model Of Smoke and Action), which integrates an underground coal mine virtual environment, a fire and smoke propagation model, and a human physiology and behavior model. Each individual agent has a set of physiological parameters as variables of time and environment, simulating a miner’s physiological condition during normal operations as well as during emergencies due to fire and smoke. To obtain appropriate agent navigation in the mine environment, we have extended the HiDAC framework (High- Density Autonomous Crowds) navigation from a grid-based cell-portal graph to a geometrybased portal path and integrated a novel cellportal and shortest path visibility algorithm.Publication Real-Time Evacuation Simulation in Mine Interior Model of Smoke and Action(2010-05-31) Huang, Pengfei; Kider, Joseph T.; Sunshine-Hill, Ben; McCaffrey, Jonathan B.; Rios, Desiree Velazquez; Badler, Norman IVirtual human crowd models have been used in the simulation of building and urban evacuation, but have not yet applied to underground coal mine operations and escape situations with emphasis on smoke, fires and physiological behaviors. We explore this through a real-time simulation model, MIMOSA (Mine Interior Model Of Smoke and Action), which integrates an underground coal mine virtual environment, a fire and smoke propagation model, and a human physiology and behavior model. Each individual agent has a set of physiological parameters as variables of time and environment, simulating a miner’s physiological condition during normal operations as well as during emergencies due to fire and smoke. To obtain appropriate agent navigation in the mine environment, we have extended the HiDAC framework (High- Density Autonomous Crowds) navigation from a grid-based cell-portal graph to a geometrybased portal path and integrated a novel cellportal and shortest path visibility algorithm.Publication All-Pairs Shortest-Paths for Large Graphs on the GPU(2008-01-01) Katz, Gary J.; Kider, Joseph T.The all-pairs shortest-path problem is an intricate part in numerous practical applications. We describe a shared memory cache efficient GPU implementation to solve transitive closure and the all-pairs shortest-path problem on directed graphs for large datasets. The proposed algorithmic design utilizes the resources available on the NVIDIA G80 GPU architecture using the CUDA API. Our solution generalizes to handle graph sizes that are inherently larger then the DRAM memory available on the GPU. Experiments demonstrate that our method is able to significantly increase processing large graphs making our method applicable for bioinformatics, internet node traffic, social networking, and routing problems.Publication CRAM It! A Comparison of Virtual, Live-Action and Written Training Systems for Preparing Personnel to Work in Hazardous Environments(2011-01-01) Stocker, Catherine; Sunshine-Hill, Ben; Drake, John; Kider, Joseph T; Badler, Norman I; Perera, IanIn this paper we investigate the utility of an interactive, desktopbased virtual reality (VR) system for training personnel in hazardous working environments. Employing a novel software model, CRAM (Course Resource with Active Materials), we asked participants to learn a specific aircraft maintenance task. The evaluation sought to identify the type of familiarization training that would be most useful prior to hands on training, as well as after, as skill maintenance. We found that participants develop an increased awareness of hazards when training with stimulating technology – in particular (1) interactive, virtual simulations and (2) videos of an instructor demonstrating a task – versus simply studying (3) a set of written instructions. The results also indicate participants desire to train with these technologies over the standard written instructions. Finally, demographic data collected during the evaluation elucidates future directions for VR systems to develop a more robust and stimulating hazard training environment.Publication A Data-Driven Appearance Model for Human Fatigue(2011-01-01) Kider, Joseph T.; Safonova, Alla; Pollock, KaitlinHumans become visibly tired during physical activity. After a set of squats, jumping jacks or walking up a flight of stairs, individuals start to pant, sweat, loose their balance, and flush. Simulating these physiological changes due to exertion and exhaustion on an animated character greatly enhances a motion’s realism. These fatigue factors depend on the mechanical, physical, and biochemical function states of the human body. The difficulty of simulating fatigue for character animation is due in part to the complex anatomy of the human body. We present a multi-modal capturing technique for acquiring synchronized biosignal data and motion capture data to enhance character animation. The fatigue model utilizes an anatomically derived model of the human body that includes a torso, organs, face, and rigged body. This model is then driven by biosignal output. Our animations show the wide range of exhaustion behaviors synthesized from real biological data output. We demonstrate the fatigue model by augmenting standard motion capture with exhaustion effects to produce more realistic appearance changes during three exercise examples. We compare the fatigue model with both simple procedural methods and a dense marker set data capture of exercise motions.Publication Fruit Senescence and Decay Simulation(2011-04-01) Kider, Joseph T.; Badler, Norman I; Raja, SamanthaAging and imperfections provide important visual cues for realism. We present a novel physically-based approach for simulating the biological aging and decay process in fruits. This method simulates interactions between multiple processes. Our biologically-derived, reaction-diffusion model generates growth patterns for areas of fungal and bacterial infection. Fungal colony spread and propagation is affected by both bacterial growth and nutrient depletion. This process changes the physical properties of the surface of the fruit as well as its internal volume substrate. The fruit is physically simulated with parameters such as skin thickness and porosity, water content, flesh rigidity, ambient temperature, humidity, and proximity to other surfaces. Our model produces a simulation that closely mirrors the progression of decay in real fruits under similar parameterized conditions. Additionally, we provide a tool that allows artists to customize the input of the program to produce generalized fruit simulations.Publication Human Model Reaching, Grasping, Looking and Sitting Using Smart Objects(2011-06-01) Slonneger, D.; Croop, Matthew; Kider, Joseph T.; Cytryn, J.; Rabbitz, R.; Badler, Norman I; Halpern, E.Manually creating convincing animated human motion in a 3D ergonomic test environment is tedious and time consuming. However, procedural motion generators help animators efficiently produce complex and realistic motions. Using the concept of a Human Modeling Software Testbed (HMST), we created novel procedural methods for animating reaching, grasping, looking, and sitting using the environmental context of ‘smart’ objects that parametrically guide human model ergonomic motions. This approach enabled complicated procedures such as collision-free leg reach and contextual sitting motion generation. By procedurally adding small secondary details to the animation, such as head/eye vision constraints and prehensile grasps, the animated motions look more natural with minimal animator input. A ‘smart’ object in the scene graph provides specific parameters to produce proper motions and final positions. These parameters are applied to the desired figure procedurally to create any secondary motions, and further generalize to any environment. Our system allows users to proceed with any required ergonomic analyses with confidence in the visual validity of the automated motions.Publication Intelligent Camera Control Using Behavior Trees(2011-11-01) Kider, Joseph T.; Markowitz, Daniel; Badler, Norman I; Shoulson, AlexanderAutomatic camera systems produce very basic animations for virtual worlds. Users often view environments through two types of cameras: a camera that they control manually, or a very basic automatic camera that follows their character, minimizing occlusions. Real cinematography features much more variety producing more robust stories. Cameras shoot establishing shots, close-ups, tracking shots, and bird’s eye views to enrich a narrative. Camera techniques such as zoom, focus, and depth of field contribute to framing a particular shot. We present an intelligent camera system that automatically positions, pans, tilts, zooms, and tracks events occurring in real-time while obeying traditional standards of cinematography. We design behavior trees that describe how a single intelligent camera might behave from low-level narrative elements assigned by “smart events”. Camera actions are formed by hierarchically arranging behavior sub-trees encapsulating nodes that control specific camera semantics. This approach is more modular and particularly reusable for quickly creating complex camera styles and transitions rather then focusing only on visibility. Additionally, our user interface allows a director to provide further camera instructions, such as prioritizing one event over another, drawing a path for the camera to follow, and adjusting camera settings on the fly.We demonstrate our method by placing multiple intelligent cameras in a complicated world with several events and storylines, and illustrate how to produce a well-shot “documentary” of the events constructed in real-time.Publication Recreating Early Islamic Glass Lamp Lighting(2009-01-01) Kider, Joseph T.; Fletcher, Rebecca; Yu, Nancy; Holod, Renata; Badler, Norman I; Chalmers, AlanEarly Islamic light sources are not simple, static, uniform points, and the fixtures themselves are often combinations of glass, water, fuel and flame. Various physically based renderers such as Radiance are widely used for modeling ancient architectural scenes; however they rarely capture the true ambiance of the environment due to subtle lighting effects. Specifically, these renderers often fail to correctly model complex caustics produced by glass fixtures, water level, and fuel sources. While the original fixtures of the 8th through 10th century Mosque of Córdoba in Spain have not survived, we have applied information gathered from earlier and contemporary sites and artifacts, including those from Byzantium, to assume that it was illuminated by either single jar lamps or supported by polycandela that cast unique downward caustic lighting patterns which helped individuals to navigate and to read. To re-synthesize such lighting, we gathered experimental archaeological data and investigated and validated how various water levels and glass fixture shapes, likely used during early Islamic times, changed the overall light patterns and downward caustics. In this paper, we propose a technique called Caustic Cones, a novel data-driven method to ‘shape’ the light emanating from the lamps to better recreate the downward lighting without resorting to computationally expensive photon mapping renderers. Additionally, we demonstrate on a rendering of the Mosque of Cordoba how our approach greatly benefits archaeologists and architectural historians by providing a more authentic visual simulation of early Islamic glass lamp lighting.