Rendering - Experimental Ideas & Implementations 2017

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https://diglib.eg.org/handle/10.2312/2631441

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Browsing Rendering - Experimental Ideas & Implementations 2017 by Subject "I.3.7 [Computer Graphics]"

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    k-d Tree Construction Designed for Motion Blur
    (The Eurographics Association, 2017) Yang, Xin; Liu, Qi; Yin, Baocai; Zhang, Qiang; Zhou, Dongsheng; Wei, Xiaopeng; Matthias Zwicker and Pedro Sander
    We present a k-d tree construction algorithm designed to accelerate rendering of scenes with motion blur, in application scenarios where a k-d tree is either required or desired. Our associated data structure focuses on capturing incoherent motion within the nodes of a k-d tree and improves both data structure quality and efficiency over previous methods. At build-time stage, we tracks primitives with motion that is significantly distinct from other primitives within the node, guarantee valid node references and the correctness of the data structure via primitive duplication heuristic and propagation rules. Our experiments with this hierarchy show artifact-free motion-blur rendering using a k-d tree, and demonstrate improvements against a traditional BVH with interpolation and a MSBVH structure designed to handle moving primitives, particularly in render time.
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    Local Quasi-Monte Carlo Exploration
    (The Eurographics Association, 2017) Tessari, Lorenzo; Hanika, Johannes; Dachsbacher, Carsten; Matthias Zwicker and Pedro Sander
    In physically-based image synthesis, the path space of light transport paths is usually explored by stochastic sampling. The two main families of algorithms are Monte Carlo/quasi-Monte Carlo sampling and Markov chain Monte Carlo. While the former is known for good uniform discovery of important regions, the latter facilitates efficient exploration of local effects. We introduce a hybrid sampling technique which uses quasi-Monte Carlo points to achieve good stratification in both stages: we use the Halton sequence to generate initial seed paths and rank-1 lattices for local exploration. This method avoids the hard problem of introducing QMC sequences into MCMC while still stratifying samples both globally and locally. We propose perturbation strategies that prefer dimensions close to the camera, facilitating efficient reuse of transport path suffixes. This framework provides maximum control of the sampling scheme by the programmer, which can be hard to achieve with Markov chain-based methods. We show that local QMC exploration can generate results on par with state of the art light transport sampling methods, while providing more uniform convergence, improving temporal consistency.
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    Material Design in Augmented Reality with In-Situ Visual Feedback
    (The Eurographics Association, 2017) Shi, Weiqi; Wang, Zeyu; Sezgin, Metin; Dorsey, Julie; Rushmeier, Holly; Matthias Zwicker and Pedro Sander
    Material design is the process by which artists or designers set the appearance properties of virtual surface to achieve a desired look. This process is often conducted in a virtual synthetic environment however, advances in computer vision tracking and interactive rendering now makes it possible to design materials in augmented reality (AR), rather than purely virtual synthetic, environments. However, how designing in an AR environment affects user behavior is unknown. To evaluate how work in a real environment influences the material design process, we propose a novel material design interface that allows designers to interact with a tangible object as they specify appearance properties. The setup gives designers the opportunity to view the real-time rendering of appearance properties through a virtual reality setup as they manipulate the object. Our setup uses a camera to capture the physical surroundings of the designer to create subtle but realistic reflection effects on the virtual view superimposed on the tangible object. The effects are based on the physical lighting conditions of the actual design space. We describe a user study that compares the efficacy of our method to that of a traditional 3D virtual synthetic material design system. Both subjective feedback and quantitative analysis from our study suggest that the in-situ experience provided by our setup allows the creation of higher quality material properties and supports the sense of interaction and immersion.