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Gen3dlife Journals Results
Coherent multi-layer landscape synthesis
Argudo, Oscar; Andújar, Carlos; Chica, Antoni; Guérin, Eric; Digne, Julie; Peytavie, Adrien; Galin, Eric
The Visual Computer, Vol. 33, Num. 6, pp 1005--1015, 2017.
DOI: http://dx.doi.org/10.1007/s00371-017-1393-6
We present an efficient method for generating coherent multi-layer landscapes. We use a dictionary built from exemplars to synthesize high-resolution fully featured terrains from input low-resolution elevation data. Our example-based method consists in analyzing real-world terrain examples and learning the procedural rules directly from these inputs. We take into account not only the elevation of the terrain, but also additional layers such as the slope, orientation, drainage area, the density and distribution of vegetation, and the soil type. By increasing the variety of terrain exemplars, our method allows the user to synthesize and control different types of landscapes and biomes, such as temperate or rain forests, arid deserts and mountains.
Error-aware Construction and Rendering of Multi-scan Panoramas from Massive Point Clouds
Comino, Marc; Andújar, Carlos; Chica, Antoni; Brunet, Pere
Computer Vision and Image Understanding, Vol. 157, pp 43--54, 2017.
DOI: http://dx.doi.org/10.1016/j.cviu.2016.09.011
Obtaining 3D realistic models of urban scenes from accurate range data is nowadays an important research topic, with applications in a variety of fields ranging from Cultural Heritage and digital 3D archiving to monitoring of public works. Processing massive point clouds acquired from laser scanners involves a number of challenges, from data management to noise removal, model compression and interactive visualization and inspection. In this paper, we present a new methodology for the reconstruction of 3D scenes from massive point clouds coming from range lidar sensors. Our proposal includes a panorama-based compact reconstruction where colors and normals are estimated robustly through an error-aware algorithm that takes into account the variance of expected errors in depth measurements. Our representation supports efficient, GPU-based visualization with advanced lighting effects. We discuss the proposed algorithms in a practical application on urban and historical preservation, described by a massive point cloud of 3.5 billion points. We show that we can achieve compression rates higher than 97% with good visual quality during interactive inspections.
Díaz, Jose; Ropinski, Timo; Navazo, Isabel; Gobbetti, Enrico; Vázquez, Pere-Pau
The Visual Computer, Vol. 33, Num. 1, pp 47-61, 2017.
DOI: http://dx.doi.org/10.1007/s00371-015-1151-6
Throughout the years, many shading techniques have been developed to improve the conveying of information in volume visualization. Some of these methods, usually referred to as realistic, are supposed to provide better cues for the understanding of volume data sets. While shading approaches are heavily exploited in traditional monoscopic setups, no previous study has analyzed the effect of these techniques in virtual reality. To further explore the influence of shading on the understanding of volume data in such environments, we carried out a user study in a desktop-based stereoscopic setup. The goals of the study were to investigate the impact of well-known shading approaches and the influence of real illumination on depth perception. Participants had to perform three different perceptual tasks when exposed to static visual stimuli. 45 participants took part in the study, giving us 1152 trials for each task. Results show that advanced shading techniques improve depth perception in stereoscopic volume visualization. As well, external lighting does not affect depth perception when these shading methods are applied. As a result, we derive some guidelines that may help the researchers when selecting illumination models for stereoscopic rendering.
Intersecting two families of sets on the GPU
Fort, Marta; Sellarès, J. Antoni; Valladares, Ignacio
Journal of Parallel and Distributed Computing, 2017.
DOI: http://dx.doi.org/https://doi.org/10.1016/j.jpdc.2017.01.026
The computation of the intersection family of two large families of unsorted sets is an interesting problem from the mathematical point of view which also appears as a subproblem in decision making applications related to market research or temporal evolution analysis problems. The problem of intersecting two families of sets F and F′ is to find the family I of all the sets which are the intersection of some set of F and some other set of F′. In this paper, we present an efficient parallel GPU-based approach, designed under CUDA architecture, to solve the problem. We also provide an efficient parallel GPU strategy to summarize the output by removing the empty and duplicated sets of the obtained intersection family, maintaining, if necessary, the sets frequency. The complexity analysis of the presented algorithm together with experimental results obtained with its implementation is also presented.
Hermosilla, Pedro; Jorge Estrada; Víctor Guallar; Timo Ropinsky; Vinacua, Àlvar; Vázquez, Pere-Pau
IEEE Transactions on Visualization and Computer Graphics, Vol. 23, Num. 1, pp 731--740, 2017.
DOI: http://dx.doi.org/10.1109/TVCG.2016.2598825
Molecular simulations are used in many areas of biotechnology, such as drug design and enzyme engineering. Despite the development of automatic computational protocols, analysis of molecular interactions is still a major aspect where human comprehension and intuition are key to accelerate, analyze, and propose modifications to the molecule of interest. Most visualization algorithms help the users by providing an accurate depiction of the spatial arrangement: the atoms involved in inter-molecular contacts. There are few tools that provide visual information on the forces governing molecular docking. However, these tools, commonly restricted to close interaction between atoms, do not consider whole simulation paths, long-range distances and, importantly, do not provide visual cues for a quick and intuitive comprehension of the energy functions (modeling intermolecular interactions) involved. In this paper, we propose visualizations designed to enable the characterization of interaction forces by taking into account several relevant variables such as molecule-ligand distance and the energy function, which is essential to understand binding affinities. We put emphasis on mapping molecular docking paths obtained from Molecular Dynamics or Monte Carlo simulations, and provide time-dependent visualizations for different energy components and particle resolutions: atoms, groups or residues. The presented visualizations have the potential to support domain experts in a more efficient drug or enzyme design process.
Hermosilla, Pedro; Michael Krone; Víctor Guallar; Vázquez, Pere-Pau; Vinacua, Àlvar; Timo Ropinsky
The Visual Computer, Vol. 33, Num. 6, pp 869--881, 2017.
DOI: http://dx.doi.org/10.1007/s00371-017-1397-2
The Solvent Excluded Surface (SES) is a popular molecular representation that gives the boundary of the molecular volume with respect to a specific solvent. SESs depict which areas of a molecule are accessible by a specific solvent, which is represented as a spherical probe. Despite the popularity of SESs, their generation is still a compute-intensive process, which is often performed in a preprocessing stage prior to the actual rendering (except for small models). For dynamic data or varying probe radii, however, such a preprocessing is not feasible as it prevents interactive visual analysis. Thus, we present a novel approach for the on-the-fly generation of SESs, a highly parallelizable, grid-based algorithm where the SES is rendered using ray-marching. By exploiting modern GPUs, we are able to rapidly generate SESs directly within the mapping stage of the visualization pipeline. Our algorithm can be applied to large time-varying molecules and is scalable, as it can progressively refine the SES if GPU capabilities are insufficient. In this paper, we show how our algorithm is realized and how smooth transitions are achieved during progressive refinement. We further show visual results obtained from real world data and discuss the performance obtained, which improves upon previous techniques in both the size of the molecules that can be handled and the resulting frame rate.
Argudo, Oscar; Besora, Isaac; Brunet, Pere; Creus, Carles; Hermosilla, Pedro; Navazo, Isabel; Vinacua, Àlvar
Computer-Aided Design, Vol. 79, pp 48--59, 2016.
DOI: http://dx.doi.org/10.1016/j.cad.2016.06.005
The use of virtual prototypes and digital models containing thousands of individual objects is commonplace in complex industrial applications like the cooperative design of huge ships. Designers are interested in selecting and editing specific sets of objects during the interactive inspection sessions. This is however not supported by standard visualization systems for huge models. In this paper we discuss in detail the concept of rendering front in multiresolution trees, their properties and the algorithms that construct the hierarchy and efficiently render it, applied to very complex CAD models, so that the model structure and the identities of objects are preserved. We also propose an algorithm for the interactive inspection of huge models which uses a rendering budget and supports selection of individual objects and sets of objects, displacement of the selected objects and real-time collision detection during these displacements. Our solution ---based on the analysis of several existing view-dependent visualization schemes--- uses a Hybrid Multiresolution Tree that mixes layers of exact geometry, simplified models and impostors, together with a time-critical, view-dependent algorithm and a Constrained Front. The algorithm has been successfully tested in real industrial environments; the models involved are presented and discussed in the paper.
Single-picture reconstruction and rendering of trees for plausible vegetation synthesis
Argudo, Oscar; Chica, Antoni; Andújar, Carlos
Computers & Graphics, Vol. 57, pp 55--67, 2016.
DOI: http://dx.doi.org/10.1016/j.cag.2016.03.005
State-of-the-art approaches for tree reconstruction either put limiting constraints on the input side (requiring multiple photographs, a scanned point cloud or intensive user input) or provide a representation only suitable for front views of the tree. In this paper we present a complete pipeline for synthesizing and rendering detailed trees from a single photograph with minimal user effort. Since the overall shape and appearance of each tree is recovered from a single photograph of the tree crown, artists can benefit from georeferenced images to populate landscapes with native tree species. A key element of our approach is a compact representation of dense tree crowns through a radial distance map. Our first contribution is an automatic algorithm for generating such representations from a single exemplar image of a tree. We create a rough estimate of the crown shape by solving a thin-plate energy minimization problem, and then add detail through a simplified shape-from-shading approach. The use of seamless texture synthesis results in an image-based representation that can be rendered from arbitrary view directions at different levels of detail. Distant trees benefit from an output-sensitive algorithm inspired on relief mapping. For close-up trees we use a billboard cloud where leaflets are distributed inside the crown shape through a space colonization algorithm. In both cases our representation ensures efficient preservation of the crown shape. Major benefits of our approach include: it recovers the overall shape from a single tree image, involves no tree modeling knowledge and minimal authoring effort, and the associated image-based representation is easy to compress and thus suitable for network streaming.
Beacco, Alejandro; Pelechano, Nuria; Andújar, Carlos
Computer Graphics Forum, Vol. 35, Num. 8, pp 32--50, 2016.
DOI: http://dx.doi.org/10.1111/cgf.12774
In this survey we review, classify and compare existing approaches for real-time crowd rendering. We first overview character animation techniques, as they are highly tied to crowd rendering performance, and then we analyze the state of the art in crowd rendering. We discuss different representations for level-of-detail (LoD) rendering of animated characters, including polygon-based, point-based, and image-based techniques, and review different criteria for runtime LoD selection. Besides LoD approaches, we review classic acceleration schemes, such as frustum culling and occlusion culling, and describe how they can be adapted to handle crowds of animated characters. We also discuss specific acceleration techniques for crowd rendering, such as primitive pseudo-instancing, palette skinning, and dynamic key-pose caching, which benefit from current graphics hardware. We also address other factors affecting performance and realism of crowds such as lighting, shadowing, clothing and variability. Finally we provide an exhaustive comparison of the most relevant approaches in the field.
3D Model deformations with arbitrary control points
Cerveró, M.Àngels; Brunet, Pere; Vinacua, Àlvar
Computer & Graphics, Vol. 57, pp 92-101, 2016.
DOI: http://dx.doi.org/10.1016/j.cag.2016.03.010
Cage-based space deformations are often used to edit and animate images and geometric models. The deformations of the cage are easily transferred to the model by recomputing fixed convex combinations of the vertices of the cage, the control points. In current cage-based schemes the configuration of edges and facets between these control points affects the resulting deformations. In this paper we present a family of similar schemes that includes some of the current techniques, but also new schemes that depend only on the positions of the control points. We prove that these methods afford a solution under fairly general conditions and result in an easy and flexible way to deform objects using freely placed control points, with the necessary conditions of positivity and continuity.
Díaz-García, Jesús; Brunet, Pere; Navazo, Isabel; Perez, Frederic; Vázquez, Pere-Pau
Computer Graphics International , Vol. 32, Num. 6, pp 835--845, 2016.
DOI: http://dx.doi.org/10.1007/s00371-016-1253-9
Medical datasets are continuously increasing in size. Although larger models may be available for certain research purposes, in the common clinical practice the models are usually of up to 512×512×2000 voxels. These resolutions exceed the capabilities of conventional GPUs, the ones usually found in the medical doctors’ desktop PCs. Commercial solutions typically reduce the data by downsampling the dataset iteratively until it fits the available target specifications. The data loss reduces the visualization quality and this is not commonly compensated with other actions that might alleviate its effects. In this paper, we propose adaptive transfer functions, an algorithm that improves the transfer function in downsampled multiresolution models so that the quality of renderings is highly improved. The technique is simple and lightweight, and it is suitable, not only to visualize huge models that would not fit in a GPU, but also to render not-so-large models in mobile GPUs, which are less capable than their desktop counterparts. Moreover, it can also be used to accelerate rendering frame rates using lower levels of the multiresolution hierarchy while still maintaining high-quality results in a focus and context approach. We also show an evaluation of these results based on perceptual metrics.
Pelechano, Nuria; Fuentes, Carlos
Computers & Graphics, Vol. 59, pp 68--78, 2016.
DOI: http://dx.doi.org/10.1016/j.cag.2016.05.023
Path-finding can become an important bottleneck as both the size of the virtual environments and the number of agents navigating them increase. It is important to develop techniques that can be efficiently applied to any environment independently of its abstract representation. In this paper we present a hierarchical NavMesh representation to speed up path-finding. Hierarchical path-finding (HPA*) has been successfully applied to regular grids, but there is a need to extend the benefits of this method to polygonal navigation meshes. As opposed to regular grids, navigation meshes offer representations with higher accuracy regarding the underlying geometry, while containing a smaller number of cells. Therefore, we present a bottom-up method to create a hierarchical representation based on a multilevel k-way partitioning algorithm (MLkP), annotated with sub-paths that can be accessed online by our Hierarchical NavMesh Path-finding algorithm (HNA*). The algorithm benefits from searching in graphs with a much smaller number of cells, thus performing up to 7.7 times faster than traditional A⁎ over the initial NavMesh. We present results of HPA* over a variety of scenarios and discuss the benefits of the algorithm together with areas for improvement.
Immersive data comprehension: visualizing uncertainty in measurable models
Brunet, Pere; Andújar, Carlos
Frontiers in Robotics and AI, Virtual Environments, pp 2-22, 2015.
DOI: http://dx.doi.org/ http://dx.doi.org/10.3389/frobt.2015.00022
Recent advances in 3D scanning technologies have opened new possibilities in a broad range of applications including cultural heritage, medicine, civil engineering, and urban planning. Virtual Reality systems can provide new tools to professionals that want to understand acquired 3D models. In this review paper, we analyze the concept of data comprehension with an emphasis on visualization and inspection tools on immersive setups. We claim that in most application fields, data comprehension requires model measurements, which in turn should be based on the explicit visualization of uncertainty. As 3D digital representations are not faithful, information on their fidelity at local level should be included in the model itself as uncertainty bounds. We propose the concept of Measurable 3D Models as digital models that explicitly encode such local uncertainty bounds. We claim that professionals and experts can strongly benefit from immersive interaction through new specific, fidelity-aware measurement tools, which can facilitate 3D data comprehension. Since noise and processing errors are ubiquitous in acquired datasets, we discuss the estimation, representation, and visualization of data uncertainty. We show that, based on typical user requirements in Cultural Heritage and other domains, application-oriented measuring tools in 3D models must consider uncertainty and local error bounds. We also discuss the requirements of immersive interaction tools for the comprehension of huge 3D and nD datasets acquired from real objects.
Hermosilla, Pedro; Guallar, Víctor; Vinacua, Àlvar; Vázquez, Pere-Pau
Computers & Graphics, Vol. 54, pp 113-120, 2015.
DOI: http://dx.doi.org/10.1016/j.cag.2015.07.017
All-atom simulations are crucial in biotechnology. In Pharmacology, for example, molecular knowledge of protein-drug interactions is essential in the understanding of certain pathologies and in the development of improved drugs. To achieve this detailed information, fast and enhanced molecular visualization is critical. Moreover, hardware and software developments quickly deliver extensive data, providing intermediate results that can be analyzed by scientists in order to interact with the simulation process and direct it to a more promising configuration. In this paper we present a GPU-friendly data structure for real-time illustrative visualization of all-atom simulations. Our system generates both ambient occlusion and halos using an occupancy pyramid that needs no precalculation and that is updated on the fly during simulation, allowing the real time rendering of simulation results at sustained high framerates.
Ramirez-Flores, J.E.; Susin, Antonio
Computer Animation and Virtual Worlds, 2015.
DOI: http://dx.doi.org/10.1002/cav.1687
Skeleton-driven animation is popular by its simplicity and intuitive control of the limbs of a character. Linear blend skinning (LBS) is up to date the most efficient and simple deformation method; however, painting influence skinning weights is not intuitive, and it suffers the candy-wrapper artifact. In this paper, we propose an approach based on mesh segmentation for skinning and skeleton-driven computer animation. We propose a novel and fast method, based in watershed segmentation to deal with characters in T-Pose and arbitrary poses, a simple weight assign algorithm based in the rigid skinning obtained with the segmentation algorithm for the LBS deformation method, and finally, a modified version of the LBS that avoids the loss of volume in twist rotations using the segmentation stage output values.
Real-Time Molecular Visualization Supporting Diffuse Illumination and Ambient Occlusion
Skanberg, Robin; Vázquez, Pere-Pau; Guallar, Victor; Ropinski, Timo
IEEE Transactions on Visualization and Computer Graphics, Vol. 22, Num. 1, pp 718-27, 2015.
DOI: http://dx.doi.org/10.1109/TVCG.2015.2467293
Today molecular simulations produce complex data sets capturing the interactions of molecules in detail. Due to the complexity of this time-varying data, advanced visualization techniques are required to support its visual analysis. Current molecular visualization techniques utilize ambient occlusion as a global illumination approximation to improve spatial comprehension. Besides these shadow-like effects, interreflections are also known to improve the spatial comprehension of complex geometric structures. Unfortunately, the inherent computational complexity of interreflections would forbid interactive exploration, which is mandatory in many scenarios dealing with static and time-varying data. In this paper, we introduce a novel analytic approach for capturing interreflections of molecular structures in real-time. By exploiting the knowledge of the underlying space filling representations, we are able to reduce the required parameters and can thus apply symbolic regression to obtain an analytic expression for interreflections. We show how to obtain the data required for the symbolic regression analysis, and how to exploit our analytic solution to enhance interactive molecular visualizations.
Gen3dlife Conferences Results
Víctor Ceballos; Monclús, Eva; Vázquez, Pere-Pau; Bendezú, Álvaro; Mego, Marianela; Merino, Xavier; Navazo, Isabel; Azpiroz, Fernando
EuroVis 2017 - 19th EG/VGTC Conference on Visualization, 2017.
DOI: http://dx.doi.org/10.2312/eurp.20171184
The analysis of the morphology and content of the gut is necessary in order to understand metabolic and functional gut activity and for diagnostic purposes. Magnetic resonance imaging (MRI) has become an important modality technique since it is able to visualize soft tissues using no ionizing radiation, and hence removes the need for any contrast agents. In the last few years, MRI of gastrointestinal function has advanced substantially, although scarcely any publication has been devoted to the analysis of the colon content. This paper presents a semi-automatic segmentation tool for the quantitative assessment of the unprepared colon from MRI images. This application has allowed for the analysis of the colon content in various clinical experiments. The results of the assessment have contributed to a better understanding of the functionality of the colon under different diet conditions. The last experiment carried out by medical doctors showed a marked influence of diet on colonic content, accounting for about 30% of the volume variations.
Ordering Triangles in Triangulated Terrains Over Regular Grids
Alonso, Jesús; Joan Arinyo, Robert
CEIG'16, 2016.
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In this work we report on a set of rules to visit triangles in triangulated height fields defined over regular grids in a back-to-front order with respect to an arbitrary viewpoint. With the viewpoint, we associate an axis-alligned local reference framework. Projections on the $XY$ plane of the local axis and the bisector of the first and third quadrants define six sectors. Specific visiting rules for collections of triangles that project on each sector are then defined. The experiments conducted show that the implementation of a simple algorithm based on the set of visiting rules defined allows real time interaction when the viewing position moves along an arbitrary 3D path.
Human-Document Interaction systems - a new frontier for document image analysis
Dimosthenis Karatzas; Vincent Poulain d’Andecy; Marçal Rusiñol; Chica, Antoni; Vázquez, Pere-Pau
Proceedings of the International Workshop on Document Analysis Systems (DAS), 2016.
All indications show that paper documents will not cede in favour of their digital counterparts, but will instead be used increasingly in conjunction with digital information. An open challenge is how to seamlessly link the physical with the digital -how to continue taking advantage of the important affordances of paper, without missing out on digital functionality. This paper presents the authors’ experience with developing systems for Human-Document Interaction based on augmented document interfaces and examines new challenges and opportunities arising for the document image analysis field in this area. The system presented combines state of the art camera-based document image analysis techniques with a range of complementary technologies to offer fluid Human-Document Interaction. Both fixed and nomadic setups are discussed that have gone through user testing in real-life environments, and use cases are presented that span the spectrum from business to educational applications.
Enhanced Magnification for Reduced Movement in Virtual Reality Environments
Monclús, Eva; Navazo, Isabel; Vázquez, Pere-Pau
International Conference on Computer Graphics, Visualization, Computer Vision and image Processing (IADIS'16), pp 149--156, 2016.
Although Virtual Reality (VR) environments have seen slower adoption rates than expected among the medical community, throughout the last years, several new techniques and devices (e.g. Oculus Rift) have been developed that might boost the popularity of VR. However, the use of 3D environments is not exempt of some shortcomings, such as the difficulties of adaption to 3D, that sometimes produces motion sickness, or the increase in effort the user has to undergo when interacting with a 3D system, as compared to using a simple mouse on a desktop. Our proposal is tailored to focus on the second problem. More concretely, we propose a magnification technique that is able to reduce the movements required to explore a concrete part of a volumetric dataset as compared to other zooming techniques. Our technique, builds the zooming result in the same virtual position of the initial interaction while still maintaining a contextual view on the region of interest and its surroundings. This way, the user reduces the amount of movements required to explore a model and efficiency is increased. An informal user study was carried out that confirmed our hypotheses.
Pelechano, Nuria; Jan Allbeck
IEEE VR Workshop on Virtual Humans and Crowds for Immersive Environment. VHCIE, 2016.
A software framework for the development of projection-based Augmented Reality Systems
Sunet, Marc; Comino, Marc; Karatzas, Dimosthenis; Chica, Antoni; Vázquez, Pere-Pau
IADIS Computer Graphics, Visualization, Computer Vision and Image Processing, 2016.
Despite the large amount of methods and applications of augmented reality, there is little homogenization on the software platforms that support them. An exception may be the low level control software that is provided by some high profile vendors such as Qualcomm and Metaio. However, these provide fine grain modules for e.g. element tracking. We are more concerned on the application framework, that includes the control of the devices working together for the development of the AR experience. In this paper we present a soft- ware framework that can be used for the development of AR applications based on camera-projector pairs, that is suitable for both fixed, and nomadic setups.
Sunet, Marc; Vázquez, Pere-Pau
Web3D, pp 127-135, 2016.
DOI: http://dx.doi.org/10.1145/2945292.2945300
Screen space ambient occlusion is a popular dynamic global illumination technique that has seen widespread adoption in PC computer games and other applications due to its simplicity, scalability, and ability to be integrated with other techniques. Mobile platforms, however, have traditionally been unable to run screen space ambient occlusion and other global illumination techniques in real-time, forcing developers to bake most of the illumination as a consequence. In this paper, we analyze the technical aspects involved in porting Ambient Occlusion to mobile devices and propose an optimized pipeline that is able to improve Ambient Occlusion calculation in OpenGL-based pipelines. We demonstrate our optimizations by applying them to four popular techniques: Crytek, Starcraft, Alchemy, and Horizon-Based Ambient Occlusion.
Parallel GPU Collision Computation in Conformal Warped Space For Surface Detail Haptic
Theoktisto, Víctor; Fairén, Marta; Navazo, Isabel
13th International Congress on Numerical Methods in Engineering and Applied Sciences, 2016.
GPU for rendering accurate touch sensation in highly complex geometric models. An object’s geometry is covered completely by a connected mesh of edge-joined prismoids, while surface detail is encoded by an image-based approach in a special tangent space flat texture containing relief and surface normals values. Heights and normals within each prism are warped from object volume space to orthogonal tangent space, by means fast method for computing barycentric coordinates, and stored in a per-face sorted RGBA texture. Parallel computation is performed in GPU for many prisms at once. Applying a unified treatment of collision detection in conformal space from euclidean R 3 (3D) to a higher dimensional conformal space R 4 ; 1 (5D), CUDA core kernels perform parallel real-time collision detection in GPU, with a haptic probe’s position vector without any bounding volume prefiltering, to identify which prisms of the object’s surface are being touched, and then map coordinates to tangent space, sampling relative surface height and normal from texture, for a final decision on whether the surface was h it. Results show throughput is increased between one and two orders of magnitude in collision benchmarks among known mesh models, computed in blind all vs. all manner, accurately colliding against 3D surface detail at high sampling rates without degrading touch sensation.
From One to Many:Simulating Groups of Agents with Reinforcement Learning Controllers
Casadiego, Luiselena; Pelechano, Nuria
15th International Conference on Intelligence Virtual Agents ( IVA'16), pp 119-123, 2015.
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This poster present a Reinforcement Learning (RL) approach for crowd simulation . We train an agent to move towards a goal while avoiding obstacles . Once one agent has learned, its knowledge is transferred to the rest of the members of the group by sharing the resulting Q - Table . This results in individual behavior leading to emergent group behavior . We present a framework with states, actions and reward functions general enough to easily adapt to different environment configurations .
DAPS for Degenerate Elements in FEM Simulations
Civit, Oscar; Susin, Antonio
Symposium Geometry Processing, 2015.
Fast Contact Determination for Intersecting Deformable Solids
Civit-Flores, Oscar; Susin, Antonio
In Proc. of Motion in Games (MIG'15), pp 205-214, 2015.
We present a fast contact determination scheme for intersecting deformable solids with detailed surface geometry. Given a high resolution closed surface mesh we automatically build a coarse embedding tetrahedralization and a partitioned representation of the surface in a preprocess. During simulation, the contact determination algorithm finds all intersecting pairs of deformed triangles using a memory-efficient barycentric bounding volume hierarchy, connects them into potentially disjoint intersection curves and performs a topological flood process on the exact intersection surfaces to discover a minimal set of contact points. A unique contact normal is computed for each contact volume, based on a continuous definition of surface normals, and used to find contact point correspondences suitable for contact treatment. The algorithm is strongly output-sensitive and we demonstrate robust contact determination at 60 frames per second for a pair of objects with 100K triangles in shallow intersecting contact.
InclineType: An Accelerometer-based Typing Approach for Smartwatches
Götzelmann, Timo; Vázquez, Pere-Pau
Proc. of XVI International Conference on Human Computer Interaction, pp 59:1-59:4, 2015.
Instant Visualization of Secondary Structures of Molecular Models
Hermosilla, Pedro; Guallar, Víctor; Vinacua, Àlvar; Vázquez, Pere-Pau
In Proc. of Eurographics Workshop on Visual Computing for Biology and Medicine, pp 51-60, 2015.
DOI: http://dx.doi.org/10.2312/vcbm.20151208
Molecular Dynamics simulations are of key importance in the drug design field. Among all possible representations commonly used to inspect these simulations, Ribbons has the advantage of giving the expert a good overview of the conformation of the molecule. Although several techniques have been previously proposed to render ribbons, all of them have limitations in terms of space or calculation time, making them not suitable for real-time interaction with simulation software. In this paper we present a novel adaptive method that generates ribbons in real-time, taking advantage of the tessellation shader. The result is a fast method that requires no precomputation, and that generates high quality shapes and shading.
Surinyac, Jordi; Brunet, Pere
XXV Spanish Computer Graphics Conference, pp 61-70, 2015.
DOI: http://dx.doi.org/10.2312/ceig.20151201
Nowadays, an increasing interest on tele-medicine and tele-diagnostic solutions can be observed, with client/server architectures for remote inspection of volume image-based medical data which are becoming more and more popular. The use of portable devices is gradually spreading due to their portability and easy maintenance. In this paper, we present an efficient data model for segmented volume models based on a hierarchical data structure of surfels per anatomical structure. Surfel Octrees are compact enough for transmission through networks with limited bandwidth, and provide good visual quality in the client devices at a limited footprint. Anatomy atlases are represented as octree forests, supporting local interaction in the client device and selection of groups of medical organs. After presenting the octree generation and interaction algorithms, we present several examples and discuss the interest of the proposed approach in low-end devices such as mobiles and tablets
Gen3dlife PhD Thesis Results
On Some Interactive Mesh Deformations
Cerveró Abelló, Maria del Àngels
PhD. Thesis. January 2016.
Advisors: Brunet, Pere; Vinacua, Àlvar
Civit-Flores, Oscar
PhD. Thesis. February 2016.
Advisors: Susin, Antonio
Ramírez Flores, Jorge Eduardo
PhD. Thesis. February 2016.
Advisors: Susin, Antonio
Enhancing detailed haptic relief for real-time interaction
Theoktisto Costa, Victor
PhD. Thesis. November 2015.
Advisors: Fairén, Marta; Navazo, Isabel