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Now showing 1 - 8 of 8
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    Modelling the Fluid-Boundary Interaction in SPH
    (The Eurographics Association, 2018) Perea, Juan J.; Cordero, Juan M.; García-Fernández, Ignacio and Ureña, Carlos
    Smoothed Particle Hydrodynamics (SPH) is a numerical method based on mutually interacting meshfree particles, and has been widely applied to fluid simulation in Computer Graphics. Originally SPH does not define the behaviour of the particle system in the contour, so the different variants of SPH have been solving this deficiency with different techniques. Some of these techniques are based on fictitious forces, specular particles or semi-analytic fields. However, all these proposals present a drawback, that are may introduce additional inaccuracy as a divergent behaviour of the particle dynamics or an artificial separation between the fluid limits and the contour. To solve these limitations at this paper presents a new technique based on contour particles that are used during simulation to model the interaction with the fluid. The use of contour particles had already been used in other works to construct the contour like a particle layer. That solution presents problems especially when increasing the complexity of the contour shape. In addition, unlike other techniques, this paper presents an additional advantage, the possibility of obtaining all the dynamic magnitudes for improving efficiency and versatility.
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    Simulation of Mechanical Weathering for Modeling Rocky Terrains
    (The Eurographics Association, 2024) Mateos, Diego; Carranza, Luis; Susin, Anton; Argudo, Oscar; Marco, Julio; Patow, Gustavo
    Synthetic terrains play a vital role in various applications, including entertainment, training, and simulation. This work focuses on rocky terrains akin to those found in alpine environments, which contain many complex features such as sharp ridges, loose blocks, or overhangs that are often inadequately represented by standard 2D elevation maps. We propose a novel method based on a simplified simulation of mechanical erosion processes commonly observed in high-altitude terrains, in particular the weathering due to freeze-thaw cycles. The ultimate objective is to generate plausible rocky geometry from existing 3D models, as well as account for the temporal evolution due to these weathering processes. Additionally, we have developed an artist-friendly tool integrated as an add-on into Blender.
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    Modal Locomotion of C. elegans
    (The Eurographics Association, 2019) Mujika, Andoni; Merino, Sara; Leškovský, Peter; Epelde, Gorka; Oyarzun, David; Otaduy, Miguel Angel; Casas, Dan and Jarabo, Adrián
    Caenorhabditis elegans (C. elegans) is a roundworm that, thanks to its combination of biological simplicity and behavioral richness, offers an excellent opportunity for initial experimentation of many human diseases. In this work, we introduce a locomotion model for C. elegans, which can enable in-silico validation of behavioral experiments prior to physical experimentation with actual C. elegans specimens. Our model enables interactive simulation of self-propelling C. elegans, using as sole input biologically inspired muscle forces and frictional contact. The key to our model is a simple locomotion control strategy that activates selected natural vibration modes of the worm. We perform an offline analysis of the natural vibration modes, select those that best match the deformation of the worm during locomotion, and design force profiles that activate these vibration modes in a coordinated manner. Together with force compensation for momentum conservation and an anisotropic friction model, we achieve locomotions that match qualitatively those of real-world worms. Our approach is general, and could be extended to the locomotion of other types of animals or characters.
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    Toward Estimation of Yarn-Level Cloth Simulation Models
    (The Eurographics Association, 2018) Martín-Garrido, Alberto; Miguel, Eder; Otaduy, Miguel Ángel; García-Fernández, Ignacio and Ureña, Carlos
    Efficient and realistic cloth simulation is an unsolved problem, with yarn-level models emerging as a new alternative thanks to new hardware capabilities. Modeling yarns as flexible rods with persistent contacts enables a very robust and efficient simulation. However, this assumption also complicates the definition of elastic deformation potentials. This work explores more accurate yarn-level cloth models together with experiments that compare model features in order to detect shortcomings in the persistent contact model. In particular, we have implemented a discrete elastic model of flexible yarns with contact which treats yarns as unidimensional splines, together with a model that discretizes yarns using three-dimensional finite elements.
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    Generación de fenómenos naturales mediante la simulación realista de sólidos deformables en Bifrost
    (The Eurographics Association, 2021) Cruz, José; Jurado, Juan Manuel; Jiménez-Pérez, J. Roberto; Ortega, Lidia; Ortega, Lidia M. and Chica, Antonio
    La simulación de fluidos y sólidos deformables ha sido ampliamente estudiada en Informática Gráfica. Existen diferentes soluciones que posibilitan una simulación cada vez más realista en entornos del mundo real. Para ello, los objetos se modelan geométricamente utilizando una malla de partículas. Esto permite la deformación de medios continuos asociando un conjunto de atributos a cada partícula que determinan su comportamiento y el de sus vecinas. En este trabajo se propone una herramienta interdisciplinar con la que generar simulaciones de fenómenos naturales como avalanchas o inundaciones. Gracias a este tipo de simulaciones físicamente realistas se consigue una manera efectiva de predecir y evaluar con un alto nivel de detalle el impacto producido por distintos tipos de desastres naturales.
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    A Virtual Reality Front-End for Earthquake Simulation
    (The Eurographics Association, 2019) Fita, Josep Lluis; Besuievsky, Gonzalo; Patow, Gustavo A.; Casas, Dan and Jarabo, Adrián
    Virtual Reality has traditionally been used in Cultural Heritage for giving to the final user an immersive experience over recreated scenarios, which usually have been designed and focused on static environment recreation. In spite of its importance for cultural heritage, we have found a lack of virtual reality applications to recreate structural and seismic simulations on historical buildings. In this paper we describe a low-cost virtual reality solution, affordable for all kinds of users that own a smart-phone. Through our application, the users can have an immersive experience that combines the ancient building recreation, its structural simulation and the natural phenomena simulation like earthquakes.
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    Simulation Based Initial Feasibility Analysis Pipeline for Small-sized Part Picking
    (The Eurographics Association, 2022) Mendizabal-Arrieta, Iñigo; Tammaro, Antonio; Ojer, Marco; Lin, Xiao; Posada, Jorge; Serrano, Ana
    Random bin picking is still one of the main tasks for robotics in the current days. When the environment is very cluttered, the calculation of grasping positions can be highly demanding in terms of time and computing power. To ease the computation load, some parts arranging operations can be performed before the segmentation stage. For instance, for small and light parts, a feeder-vibrating table system can be used to separate the components, allowing them to be easily grasped, and increasing the overall performance of the solution. However, as the geometry and requirements for piece type are different, one or more feasibility tests need to be done for each case. These analyses are usually very time and cost intensive and require the use of expensive hardware such as robots, grippers, and prototype cells. The use of virtual reproductions of the environment like digital twins or physical-based simulations could help reduce the time and effort spent on designing the settings, nevertheless, their correct configuration is not trivial. This paper presents a simulation based analysis method for picking small-sized parts. It aims to supply the tools and define a streamlined procedure for efficient feasibility testing. Those concepts are applied in a specific bin picking scenario of multiple small electronic components. For each part type, a set of case-specific initial and boundary conditions are taken into account, then a series of performance metrics for both bin and vibrating table part picking are computed. The obtained information is decisive to make strategic decisions regarding the hardware requirements, the profitability, and the success probability of the project.
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    An Improved Parallel Technique for Neighbour Search on CUDA
    (The Eurographics Association, 2017) Perea, Juan J.; Cordero, Juan M.; Fco. Javier Melero and Nuria Pelechano
    In Computer Graphics is usual the modelling of dynamic systems through particles. The simulation of liquids, cloths, gas, smoke... are highlighted examples of that modelling. In this scope, is particularly relevant the procedure of neighbour particles searching, which represents a bottleneck in terms of computational cost. One of the most used searching techniques is the cell- based spatial division by cubes, where each cell is tagged by a hash value. Thus, all particles located into each cell have the same tag and are the candidate to be neighbours. The most useful feature of this technique is that it can be easily parallelized, what reduces the computational costs. Nevertheless, the parallelizing process has some drawbacks associated with data memory management. Also, during the process of neighbour search, it is necessary to trace into the adjacent cells to find neighbour particles, as a consequence, the computational cost is increased. To solve these shortcomings, we have developed a method that reduces the search space by considering the relative position of each particle in its own cell. This method, parallelized using CUDA, shows improvements in processing time and memory management over other ''standard'' spatial division techniques.