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Item Area Lights in Signed Distance Function Scenes(The Eurographics Association, 2019) Bán, Róbert; Bálint, Csaba; Valasek, Gábor; Cignoni, Paolo and Miguel, EderThis paper presents two algorithms to incorporate spherical and general area lights into scenes defined by signed distance functions. The first algorithm employs an efficient approximation to the contribution of spherical lights to direct illumination and renders them at real-time rates. The second algorithm is of superior quality at a higher computational cost which is better suited for interactive rates. Our results are compared to both real-time soft shadow algorithms and a ground truth obtained by Monte Carlo integration. We show in these comparisons that our real-time solution computes more accurate shadows while the more demanding variant outperforms Monte Carlo integration at the expense of accuracy.Item Perceptual Characteristics by Motion Style Category(The Eurographics Association, 2019) Kim, Hye Ji; Lee, Sung-Hee; Cignoni, Paolo and Miguel, EderMotion style is important as it characterizes a motion by expressing the context of the motion such as emotion and personality. Yet, the perception and interpretation of motion styles is subjective and may vary greatly from person to person. This paper investigates the perceptual characteristics of motion styles for a wide range of styles. After categorizing the motion styles, we perform user studies to examine the diversity of interpretations of motion styles and the association level between style motions and their corresponding text descriptions. Our study shows that motion styles have different interpretation diversity and association level according to their categories. We discuss the implications of these findings and recommend a method of labeling or describing motion styles.Item Color Reproduction Framework for Inkjet FDM 3D Printers(The Eurographics Association, 2021) Silapasuphakornwong, Piyarat; Punpongsanon, Parinya; Panichkriangkrai, Chulapong; Sueeprasan, Suchitra; Uehira, Kazutake; Bittner, Jirà and Waldner, ManuelaRecent advances in consumer-grade 3D printers have enabled the fabrication of personal artifacts in aesthetically pleasing full color. However, the printed colors are usually different from the actual user desired colors due to the mismatching of droplets when the color reproduction workflow has been changed or the color profile setup is missing. In this paper, we present a preliminary experiment to investigate color reproduction errors in consumer-grade inkjet FDM 3D printers. Our results suggest that solving the problem requires initiating the workflow to minimize color reproduction errors such as using CMYK or sRGB color profiles. We also found that the mismatched color gamut between the input's desired texture and the 3D printed output depends on different file formats, and this finding requires future investigation.Item A Survey of Control Mechanisms for Creative Pattern Generation(The Eurographics Association and John Wiley & Sons Ltd., 2021) Gieseke, Lena; Asente, Paul; Mech, Radomir; Benes, Bedrich; Fuchs, Martin; Bühler, Katja and Rushmeier, HollyWe review recent methods in 2D creative pattern generation and their control mechanisms, focusing on procedural methods. The review is motivated by an artist's perspective and investigates interactive pattern generation as a complex design problem. While the repetitive nature of patterns is well-suited to algorithmic creation and automation, an artist needs more flexible control mechanisms for adaptable and inventive designs. We organize the state of the art around pattern design features, such as repetition, frames, curves, directionality, and single visual accents. Within those areas, we summarize and discuss the techniques' control mechanisms for enabling artist intent. The discussion includes questions of how input is given by the artist, what type of content the artist inputs, where the input affects the canvas spatially, and when input can be given in the timeline of the creation process. We categorize the available control mechanisms on an algorithmic level and categorize their input modes based on exemplars, parameterization, handling, filling, guiding, and placing interactions. To better understand the potential of the current techniques for creative design and to make such an investigation more manageable, we motivate our discussion with how navigation, transparency, variation, and stimulation enable creativity. We conclude our review by identifying possible new directions that can inspire innovation for artist-centered creation processes and algorithms.Item Interactive Synthesis of 3D Geometries of Blood Vessels(The Eurographics Association, 2021) Rauch, Nikolaus; Harders, Matthias; Theisel, Holger and Wimmer, MichaelIn surgical training simulators, where various organ surfaces make up the majority of the scene, the visual appearance is highly dependent on the quality of the surface textures. Blood vessels are an important detail in this; they need to be incorporated into an organ's texture. Moreover, the actual blood vessel geometries also have to be part of the simulated surgical procedure itself, e.g. during cutting. Since the manual creation of vessel geometry or branching details on textures is highly tedious, an automatic synthesis technique capable of generating a wide range of blood vessel patterns is needed.We propose a new synthesis approach based on the space colonization algorithm. As extension, physiological constraints on the proliferation of branches are enforced to create realistic vascular structures. Our framework is capable of generating three-dimensional blood vessel networks in a matter of milliseconds, thus allowing a 3D modeller to tweak parameters in real-time to obtain a desired appearance.Item Deep Learning for Graphics(The Eurographics Association, 2018) Mitra, Niloy J.; Ritschel, Tobias; Kokkinos, Iasonas; Guerrero, Paul; Kim, Vladimir; Rematas, Konstantinos; Yumer, Ersin; Ritschel, Tobias and Telea, AlexandruIn computer graphics, many traditional problems are now better handled by deep-learning based data-driven methods. In applications that operate on regular 2D domains, like image processing and computational photography, deep networks are state-of-the-art, beating dedicated hand-crafted methods by significant margins. More recently, other domains such as geometry processing, animation, video processing, and physical simulations have benefited from deep learning methods as well. The massive volume of research that has emerged in just a few years is often difficult to grasp for researchers new to this area. This tutorial gives an organized overview of core theory, practice, and graphics-related applications of deep learning.Item Teaching Computer Graphics Based on a Commercial Product(The Eurographics Association, 2019) Smith, Gregory; Sung, Kelvin; Tarini, Marco and Galin, EricThe challenges in designing an introductory Computer Graphics (CG) course include selecting an appropriate and coherent set of topics, keeping up-to-date with the rapidly evolving industry, and aligning with the many students' fascinations that tend to stem from flashy popular media. This paper analyzes and classifies existing introductory CG classes according to their approaches in trading-off between covering foundation algorithms and focusing on application-level knowledge. The paper then observes that many application-level courses challenge students in learning and applying relevant CG concepts by building familiar graphical applications. Within this context, the paper points out that many modern commercial graphical applications, including popular game engines and 3D modeling systems, support well-defined and robust run-time scripting interfaces that allow modification and/or replacement of default system functional modules. These observations suggest the potentials of delivering an introductory CG class based on one of these commercial graphical systems. This paper proposes a set of guidelines to ensure such a class will educate CG practitioners rather than commercial product users. Based on these guidelines and an existing application-based introductory CG course, a new set of learning outcomes is derived which is independent of any specific commercial product. The paper continues to describe the implementation of a new course using the Unity3D game engine as the delivery vehicle. This paper then describes the associated teaching materials, details the hands-on programming assignments, and discusses student learning from the Unity3D-based introductory CG class. The results from two consecutive batches of students demonstrated that a commercial graphical product-based approach to teaching an introductory CG class could be effective, welcomed by students, and supply students the concepts to build practical graphical applications after the class.Item Marching Cubes for Teaching GLSL Programming(The Eurographics Association, 2021) Ilinkin, Ivaylo; Sousa Santos, Beatriz and Domik, GittaThis paper shares ideas for illustrating GLSL programming based on the classic Marching Cubes algorithm. The algorithm has a number of appealing aspects: it is feasible to implement as one of the components in a computer graphics course, it motivates naturally a number of GLSL concepts and constructs, and leaves the students with a sense of accomplishment having reproduced original research. The paper suggest possible variations and extensions that could form the basis for final group projects.Item Monte Carlo Methods for Volumetric Light Transport Simulation(The Eurographics Association and John Wiley & Sons Ltd., 2018) Novák, Jan; Georgiev, Iliyan; Hanika, Johannes; Jarosz, Wojciech; Hildebrandt, Klaus and Theobalt, ChristianThe wide adoption of path-tracing algorithms in high-end realistic rendering has stimulated many diverse research initiatives. In this paper we present a coherent survey of methods that utilize Monte Carlo integration for estimating light transport in scenes containing participating media. Our work complements the volume-rendering state-of-the-art report by Cerezo et al. [CPP 05]; we review publications accumulated since its publication over a decade ago, and include earlier methods that are key for building light transport paths in a stochastic manner. We begin by describing analog and non-analog procedures for freepath sampling and discuss various expected-value, collision, and track-length estimators for computing transmittance. We then review the various rendering algorithms that employ these as building blocks for path sampling. Special attention is devoted to null-collision methods that utilize fictitious matter to handle spatially varying densities; we import two ''next-flight'' estimators originally developed in nuclear sciences. Whenever possible, we draw connections between image-synthesis techniques and methods from particle physics and neutron transport to provide the reader with a broader context.Item Compression and Real-Time Rendering of Inward Looking Spherical Light Fields(The Eurographics Association, 2020) Hajisharif, Saghi; Miandji, Ehsan; Baravadish, Gabriel; Larsson, Per; Unger, Jonas; Wilkie, Alexander and Banterle, FrancescoPhotorealistic rendering is an essential tool for immersive virtual reality. In this regard, the data structure of choice is typically light fields since they contain multidimensional information about the captured environment that can provide motion parallax and view-dependent information such as highlights. There are various ways to acquire light fields depending on the nature of the scene, limitations on the capturing setup, and the application at hand. Our focus in this paper is on full-parallax imaging of large-scale static objects for photorealistic real-time rendering. To this end, we introduce and simulate a new design for capturing inward-looking spherical light fields, and propose a system for efficient compression and real-time rendering of such data using consumer-level hardware suitable for virtual reality applications.