EG 2013 - Short Papers

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https://diglib.eg.org/handle/10.2312/300

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Browsing EG 2013 - Short Papers by Subject "I.3.7 [Computer Graphics]"

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    Automatic Modeling of Planar-Hinged Buildings
    (The Eurographics Association, 2013) Garcia-Dorado, Ignacio; Aliaga, Daniel G.; M.- A. Otaduy and O. Sorkine
    We present a framework to automatically model and reconstruct buildings in a dense urban area. Our method is robust to noise and recovers planar features and sharp edges, producing a water-tight triangulation suitable for texture mapping and interactive rendering. Building and architectural priors, such as the Manhattan world and Atlanta world assumptions, have been used to improve the quality of reconstructions. We extend the framework to include buildings consisting of arbitrary planar faces interconnected by hinges. Given millions of initial 3D points and normals (i.e., via an image-based reconstruction), we estimate the location and properties of the building model hinges and planar segments. Then, starting with a closed Poisson triangulation, we use an energy-based metric to iteratively refine the initial model so as to attempt to recover the planar-hinged model and maintain building details where possible. Our results include automatically reconstructing a variety of buildings spanning a large and dense urban area, comparisons, and analysis of our method. The end product is an automatic method to produce watertight models that are very suitable for 3D city modeling and computer graphics applications.
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    Enhanced Lattice Boltzmann Shallow Waters for Real-time Fluid Simulations
    (The Eurographics Association, 2013) Ojeda, Jesus; Susín, Anton; M.- A. Otaduy and O. Sorkine
    We present a novel approach at simulating fluids in real-time by coupling the Lattice Boltzmann Method for Shallow Waters (LBMSW) with particle systems. The LBM can handle arbitrary underlying terrain and arbitrary fluid depth, which, in turn, allows us to extend it to track dry regions. The LBM is also two-way coupled with rigid bodies. The particle system adds more detail to the LBM; breaking waves are detected from the surface simulation and particles are generated to provide the effect, taking effectively certain amounts of fluid and reintegrating it back once they fall over again. Both the LBM and the particle simulation are implemented in CUDA, although rigid bodies are simulated in CPU. Finally, we show the effectiveness of the method on commodity hardware.
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    Perceptually Motivated Real-Time Compression of Motion Data Enhanced by Incremental Encoding and Parameter Tuning
    (The Eurographics Association, 2013) Firouzmanesh, Amirhossein; Cheng, Irene; Basu, Anup; M.- A. Otaduy and O. Sorkine
    We address the problem of efficient real-time motion data compression considering human perception. Using incremental encoding plus a database of motion primitives for each key point, our method achieves a higher or competitive compression rate with less online overhead. Trade-off between visual quality and bandwidth usage can be tuned by varying a single threshold value. A user study was performed to measure the sensitivity of human subjects to reconstruction errors in key rotation angles. Based on these evaluations we are able to perform lossy compression on the motion data without noticeable degradation in rendered qualities. While achieving real-time performance, our technique outperforms other methods in our experiments by achieving a compression ratio exceeding 50 : 1 on regular sequences.
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    Volume Controllable SPH
    (The Eurographics Association, 2013) Shinkawa, Masanori; Kawaguchi, Yoichiro; M.- A. Otaduy and O. Sorkine
    We extend a Predictive Corrective Incompressible SPH (PCISPH) algorithm to a volume controllable SPH algorithm. In order to handle volume changes, we develop a method to control fluid volume. Our method precomputes a pressure correction factor of PCISPH at various particle volume and interpolates these factors to get a factor for arbitrary particle volume. Thanks to a PCISPH's high correctiveness, our method enables both stiff volume contraction and expansion. Additionally we derive computations for density and a force by pressure to prevent instabilities and unnatural flocks near interfaces between two fluids with different particle volume. Furthermore, granular simulators based on fluid simulators are also extensible to simulate volume change of granular materials.