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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, JirÃPeople 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 Incorporating Visualization Research in Introductory Programming Course: Case Studies(The Eurographics Association, 2018) Kim, Sunghee; Post, Frits and Žára, JirÃThe importance of early research experience for undergraduate students has been stressed time and time again. This paper presents three case studies in which non-CS major students could gain a visualization research experience in their first programming course. In all case studies, students were given real climate data to visualize. In the first case study, students visualized spatial correlation between two variables (weather conditions) on a map so that viewers could infer areas in which the two variables were highly correlated in a positive or negative way, or areas with little to no correlation. In the second and third case studies, students generated single variable visualization and multidimensional visualization of two or four variables. In each of the three case studies the students were led through the process of understanding data, exploring different representations, and designing and implementing an agreed-upon visual representation. Increased number of students decided to take the next course in Computer Science compared to previous years without a research project. Feedback from the students suggests that they enjoyed using data they could understand and found the process and the final product rewarding and applicable to projects in their major and courses.Item EUROGRAPHICS 2018: CGF 37-2 STARs Frontmatter(The Eurographics Association and John Wiley & Sons Ltd., 2018) Hildebrandt, Klaus; Theobalt, Christian; Hildebrandt, Klaus; Theobalt, Christian-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 Image-Based Information Visualization Tutorial(The Eurographics Association, 2018) Hurter, Christophe; Ritschel, Tobias and Telea, AlexandruWhile many data exploration techniques are based on automatic knowledge extraction, other tools exist where the user plays the central role. This tutorial will report actual use-cases where the user interactively explores datasets and extracts relevant information. These techniques must be interactive enough to insure flexibility data exploration, therefore image-based algorithms propose a suitable solution. These algorithms, processed in parallel by the graphic card, are fast and scalable enough to support interactive big data exploration requirements.Item Audio-driven Emotional Speech Animation(The Eurographics Association, 2018) Charalambous, Constantinos; Yumak, Zerrin; Stappen, A. Frank van der; Jain, Eakta and Kosinka, JirÃWe propose a procedural audio-driven speech animation method that takes into account emotional variations in speech. Given any audio with its corresponding speech transcript, the method generates speech animation for any 3D character. The expressive speech model matches the pitch and intensity variations in audio to individual visemes. In addition, we introduce a dynamic co-articulation model that takes into account linguistic rules varying among emotions. We test our approach against two popular speech animation tools and we show that our method surpass them in a perceptual experiment.Item From Spectra to Perceptual Color: Visualization Tools for the Dimensional Reduction Achieved by the Human Color Sense(The Eurographics Association, 2018) Harvey, Joshua S.; Siviour, Clive R.; Smithson, Hannah E.; Jain, Eakta and Kosinka, JirÃPhysical colors, defined as unique combinations of photon populations whose wavelengths lie in the visible range, occupy an infinite-dimensional real Hilbert space. Any number of photon populations from the continuous spectrum of monochromatic wavelengths may be present to any positive amount. For normal vision, this space collapses to three dimensions at the retina, with any physical color eliciting just three sensor values corresponding to the excitations of the three classes of cone photoreceptor cells. While there are many mappings and visualizations of three-dimensional perceptual color space, attempts to visualize the relationship between infinite-dimensional physical color space and perceptual space are lacking. We present a visualization framework to illustrate this mathematical relation, using animation and transparency to map multiple physical colors to locations in perceptual space, revealing how the perceptual color solid can be understood as intersecting surfaces and volumes. This framework provides a clear and intuitive illustration of color metamerism.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 Boundary-aided Human Body Shape and Pose Estimation from a Single Image for Garment Design and Manufacture(The Eurographics Association, 2018) Xu, Zongyi; Zhang, Qianni; Jain, Eakta and Kosinka, JirÃCurrent virtual clothing design applications mainly use predefined virtual avatars which are created by professionals. The models are unrealistic as they lack the personalised body shapes and the simulation of human body muscle and soft tissue. To address this problem, we firstly fit the state-of-the-art parametric 3D human body model, SMPL, to 2D joints and boundary of the human body which are detected using CNN methods automatically. Considering the scenario of virtual dressing where people are usually in stable poses, we define a stable pose prior from CMU motion capture (mocap) dataset for further improving accuracy of pose estimation. Accurate estimation of human body shape and poses provides manufacturers and designers with more comprehensive human body measurements, which put a step forwards clothing design and manufacture through Internet.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.