Examinando por Autor "Barreiro, Héctor"

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Natural Tactile Interaction with Virtual Clay
(IEEE World Haptics Conference (WHC), 2021) Barreiro, Héctor; Torres, Joan; Otaduy, Miguel A.
Despite many past efforts to develop haptic experiences of virtual clay modeling, natural interaction with virtual clay remains a hard challenge. In this work, we propose a computational solution for the interactive simulation of clay-like materials with unprecedented realism, coupled with free-air tactile rendering that provides a natural tangible experience. Our solution includes a novel particle-based model of viscoplasticity for efficient interactive simulation, and an optimization-based ultrasound rendering algorithm that takes as input the interaction forces between a virtual hand model and the clay-like material. We demonstrate the effectiveness of our method through expressive creative experiences.
Robust Eulerian-on-Lagrangian Rods
(Association for Computing Machinery (ACM), 2020) Sánchez-Banderas, Rosa M.; Rodríguez, Alejandro; Barreiro, Héctor; Otaduy, Miguel A.
This paper introduces a method to simulate complex rod assemblies and stacked layers with implicit contact handling, through Eulerian-on-Lagrangian (EoL) discretizations. Previous EoL methods fail to handle such complex situations, due to ubiquitous and intrinsic degeneracies in the contact geometry, which prevent the use of remeshing and make simulations unstable. We propose a novel mixed Eulerian-Lagrangian discretization that supports accurate and efficient contact as in EoL methods, but is transparent to internal rod forces, and hence insensitive to degeneracies. By combining the standard and novel EoL discretizations as appropriate, we derive mixed statics-dynamics equations of motion that can be solved in a unified manner with standard solvers. Our solution is simple and elegant in practice, and produces robust simulations on large-scale scenarios with complex rod arrangements and pervasive degeneracies. We demonstrate our method on multi-layer yarn-level cloth simulations, with implicit handling of both intraand inter-layer contacts.
Soft-Tissue Simulation for Computational Planning of Orthognathic Surgery
(MDPI, 2021) Alcañiz, Patricia; Pérez, Jesús; Gutiérrez, Alessandro; Barreiro, Héctor; Villalobos, Ángel; Miraut, David; Illana, Carlos; Guiñales, Jorge; Otaduy, Miguel A.
Simulation technologies offer interesting opportunities for computer planning of orthognathic surgery. However, the methods used to date require tedious set up of simulation meshes based on patient imaging data, and they rely on complex simulation models that require long computations. In this work, we propose a modeling and simulation methodology that addresses model set up and runtime simulation in a holistic manner. We pay special attention to modeling the coupling of rigid-bone and soft-tissue components of the facial model, such that the resulting model is computationally simple yet accurate. The proposed simulation methodology has been evaluated on a cohort of 10 patients of orthognathic surgery, comparing quantitatively simulation results to post-operative scans. The results suggest that the proposed simulation methods admit the use of coarse simulation meshes, with planning computation times of less than 10 seconds in most cases, and with clinically viable accuracy.
Ultrasound Rendering of Tactile Interaction with Fluids
(IEEE World Haptics Conference (WHC), 2019) Barreiro, Héctor; Sinclair, Stephen; Otaduy, Miguel A.
When we interact with ﬂuid media, e.g., with our hands, we experience a spatially and temporally varying pressure ﬁeld on our skin, which depends on the density and viscosity of the ﬂuid, as well as the relative motion between our hands and the surrounding ﬂow. Ultrasound phased arrays stimulate skin in mid air by controlling pressure waves at particular spatial locations. In this work, we explore the connection between the pressure-based stimulation of ultrasound haptics and the actual pressure ﬁeld experienced when interacting with ﬂuid media, to devise a novel algorithm for ultrasoundbasedrenderingoftactileinteractionwithﬂuids.Ouralgorithm extracts the target pressure ﬁeld on a virtual hand from an interactive ﬂuid simulation, and formulates the computation of the rendered pressure as an optimization problem. We have designed an efﬁcient solver for this optimization problem, and we show results of interactive experiments with several ﬂuid simulations.