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Item A Multifragment Renderer for Material Aging Visualization(The Eurographics Association, 2018) Adamopoulos, Georgios; Moutafidou, Anastasia; Drosou, Anastasios; Tzovaras, Dimitrios; Fudos, Ioannis; Jain, Eakta and Kosinka, JirĂPeople involved in curatorial work and in preservation/conservation tasks need to understand exactly the nature of aging and to prevent it with minimal preservation work. In this scenario, it is of extreme importance to have tools to produce and visualize digital representations and models of visual surface appearance and material properties, to help the scientist understand how they evolve over time and under particular environmental conditions. We report on the development of a multifragment renderer for visualizing and combining the results of simulated aging of artwork objects. Several natural aging processes manifest themselves through change of color, fading, deformations or cracks. Furthermore, changes in the materials underneath the visible layers may be detected or simulated.Item Smooth Blended Subdivision Shading(The Eurographics Association, 2018) Bakker, Jelle; Barendrecht, Pieter J.; Kosinka, Jiri; Diamanti, Olga and Vaxman, AmirThe concept known as subdivision shading aims at improving the shading of subdivision surfaces. It is based on the subdivision of normal vectors associated with the control net of the surface. By either using the resulting subdivided normal field directly, or blending it with the normal field of the limit surface, renderings of higher visual smoothness can be obtained. In this work we propose a different and more versatile approach to blend the two normal fields, yielding not only better results, but also a proof that our blended normal field is C1.Item Rigid Body Joints in Real-Time Unified Particle Physics(The Eurographics Association, 2018) Lovrovic, Bojan; Mihajlovic, Zeljka; Diamanti, Olga and Vaxman, AmirIn this paper, we propose a physically-based method for a rigid body joint simulation. The proposed solution is based on the unified particle physics engine, a simulator that uses only particles for all the dynamic bodies. Such engines are implemented on the GPU and they simulate fluids, rigid bodies or deform-able materials like cloth or ropes. To support more complex systems like skeletal simulation, we show a joint implementation that is intuitive and unique to this environment. Four types of joints will be shown, as well as the necessary details about the rigid body data structure. This will enable the construction of a popular method called ragdoll. Lastly, a performance measurement and a comparison with alternatives will be given.Item Voxel DAGs and Multiresolution Hierarchies: From Large-Scale Scenes to Pre-computed Shadows(The Eurographics Association, 2018) Assarsson, Ulf; Billeter, Markus; Dolonius, Dan; Eisemann, Elmar; Jaspe, Alberto; Scandolo, Leonardo; Sintorn, Erik; Ritschel, Tobias and Telea, AlexandruIn this tutorial, we discuss voxel DAGs and multiresolution hierarchies, which are representations that can encode large volumes of data very efficiently. Despite a significant compression ration, an advantage of these structures is that their content can be efficiently accessed in real-time. This property enables various applications. We begin the tutorial by introducing the concepts of sparsity and of coherency in voxel structures, and explain how a directed acyclic graph (DAG) can be used to represent voxel geometry in a form that exploits both aspects, while remaining usable in its compressed from for e.g. ray casting. In this context, we also discuss extensions that cover the time domain or consider an advanced encoding strategies exploiting symmetries and entropy. We then move on to voxel attributes, such as colors, and explain how to integrate such information with the voxel DAGs. We will provide implementation details and present methods for efficiently constructing the DAGs and also cover how to efficiently access the data structures with e.g. GPU-based ray tracers. The course will be rounded of with a segment on applications. We highlight a few examples and show their results. Pre-computed shadows are a special application, which will be covered in detail. In this context, we also explain how some of previous ideas contribute to multi-resolution hierarchies, which gives an outlook on the potential generality of the presented solutions.Item Presenting a Deep Motion Blending Approach for Simulating Natural Reach Motions(The Eurographics Association, 2018) Gaisbauer, Felix; Froehlich, Philipp; Lehwald, Jannes; Agethen, Philipp; Rukzio, Enrico; Jain, Eakta and Kosinka, JirĂMotion blending and character animation systems are widely used in different domains such as gaming or simulation within production industries. Most of the established approaches are based on motion blending techniques. These approaches provide natural motions within common scenarios while inducing low computational costs. However, with increasing amount of influence parameters and constraints such as collision-avoidance, they increasingly fail or require a vast amount of time to meet these requirements. With ongoing progress in artificial intelligence and neural networks, recent works present deep learning based approaches for motion synthesis, which offer great potential for modeling natural motions, while considering heterogeneous influence factors. In this paper, we propose a novel deep blending approach to simulate non-cyclical natural reach motions based on an extension of phase functioned deep neural networks.Item Introducing a Modular Concept for Exchanging Character Animation Approaches(The Eurographics Association, 2018) Gaisbauer, Felix; Agethen, Philipp; Bär, Thomas; Rukzio, Enrico; Jain, Eakta and Kosinka, JirĂNowadays, motion synthesis and character animation systems are used in different domains ranging from gaming to medicine and production industries. In recent years, there has been a vast progress in terms of realistic character animation. In this context, motion-capture based animation systems are frequently used to generate natural motions. Other approaches use physics based simulation, statistical models or machine learning methods to generate realistic motions. These approaches are however tightly coupled with the development environment, thus inducing high porting efforts if being incorporated into different platforms. Currently, no standard exists which allows to exchange complex character animation approaches. A comprehensive simulation of complex scenarios utilizing these heterogeneous approaches is therefore not possible, yet. In a different domain than motion, the Functional Mock-up Interface standard has already solved this problem. Initially being tailored to industrial needs, the standards allows to exchange dynamic simulation approaches such as solvers for mechatronic components. We present a novel concept, extending this standard to couple arbitrary character animation approaches using a common interface.Item Exemplar Based Filtering of 2.5D Meshes of Faces(The Eurographics Association, 2018) Dihl, Leandro; Cruz, Leandro; Gonçalves, Nuno; Jain, Eakta and Kosinka, JirĂIn this work, we present a content-aware filtering for 2.5D meshes of faces. We propose an exemplar-based filter that corrects each point of a given mesh through local model-exemplar neighborhood comparison. We take advantage of prior knowledge of the models (faces) to improve the comparison. We first detect facial feature points, and create the point correctors for regions of each feature, and only use the correspondent regions for correcting a point of the filtered mesh.Item Light Field Synthesis from a Single Image using Improved Wasserstein Generative Adversarial Network(The Eurographics Association, 2018) Ruan, Lingyan; Chen, Bin; Lam, Miu Ling; Jain, Eakta and Kosinka, JirĂWe present a deep learning-based method to synthesize a 4D light field from a single 2D RGB image. We consider the light field synthesis problem equivalent to image super-resolution, and solve it by using the improved Wasserstein Generative Adversarial Network with gradient penalty (WGAN-GP). Experimental results demonstrate that our algorithm can predict complex occlusions and relative depths in challenging scenes. The light fields synthesized by our method has much higher signal-to-noise ratio and structural similarity than the state-of-the-art approach.Item State of the Art on 3D Reconstruction with RGB-D Cameras(The Eurographics Association and John Wiley & Sons Ltd., 2018) Zollhöfer, Michael; Stotko, Patrick; Görlitz, Andreas; Theobalt, Christian; NieĂźner, Matthias; Klein, Reinhard; Kolb, Andreas; Hildebrandt, Klaus and Theobalt, ChristianThe advent of affordable consumer grade RGB-D cameras has brought about a profound advancement of visual scene reconstruction methods. Both computer graphics and computer vision researchers spend significant effort to develop entirely new algorithms to capture comprehensive shape models of static and dynamic scenes with RGB-D cameras. This led to significant advances of the state of the art along several dimensions. Some methods achieve very high reconstruction detail, despite limited sensor resolution. Others even achieve real-time performance, yet possibly at lower quality. New concepts were developed to capture scenes at larger spatial and temporal extent. Other recent algorithms flank shape reconstruction with concurrent material and lighting estimation, even in general scenes and unconstrained conditions. In this state-of-the-art report, we analyze these recent developments in RGB-D scene reconstruction in detail and review essential related work. We explain, compare, and critically analyze the common underlying algorithmic concepts that enabled these recent advancements. Furthermore, we show how algorithms are designed to best exploit the benefits of RGB-D data while suppressing their often non-trivial data distortions. In addition, this report identifies and discusses important open research questions and suggests relevant directions for future work.Item RIFNOM: 3D Rotation-Invariant Features on Normal Maps(The Eurographics Association, 2018) Nakamura, Akihiro; Miyashita, Leo; Watanabe, Yoshihiro; Ishikawa, Masatoshi; Jain, Eakta and Kosinka, JirĂThis paper presents 3D rotation-invariant features on normal maps: RIFNOM.We assign a local coordinate system (CS) to each pixel by using neighbor normals to extract the 3D rotation-invariant features. These features can be used to perform interest point matching between normal maps. We can estimate 3D rotations between corresponding interest points by comparing local CSs. Experiments with normal maps of a rigid object showed the performance of the proposed method in estimating 3D rotations. We also applied the proposed method to a non-rigid object. By estimating 3D rotations between corresponding interest points, we successfully detected deformation of the object.