Sumanta Pattanaik

University of Central Florida, Orlando, Florida, United States

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Publications (93)37.96 Total impact

  • Computers & Graphics 01/2014; · 0.79 Impact Factor
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    ABSTRACT: In this paper, we present a novel approach to progressive photon-based volume rendering techniques. By making use of two Kd-trees (built in a preprocessing step) to store view beams (primary rays intersecting the medium) and visible points, our method allows to handle scenes with specular and refractive objects as well as homogeneous and heterogeneous participating media and does not require the storage of photon maps, which solves the memory management issue. These data structures are used to drive the photon shooting process by considering the photon visibility as an importance function (similarly to Hachisuka and Jensen in ACM Trans. Graph. 30(5):114:1–114:11, 2011) for scenes containing participating media. Finally, we demonstrate that our method can be easily combined with the most recent particle tracing approaches such as the one presented in Jarosz et al. (ACM Trans. Graph., vol. 30(6), 2011).
    The Visual Computer 09/2013; 29(9). · 0.91 Impact Factor
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    ABSTRACT: We present a novel technique for physically based rendering of participating media like cloud, smoke, wax, marble, etc. We solve the radiative transfer equation (RTE) for participating media using the Modified Discrete Ordinate Method (MDOM), which computes the final solution as a combination of a direct and an indirect component. We propose a scalable GPU based parallel pipeline, for solving the RTE using the MDOM. This parallel RTE solver is capable of rendering intermediate results such as single scattering approximation. We overcome GPU memory size limitations by using low resolution radiance storage while doing high resolution radiance propagation. Furthermore, we achieve scalability by implementing an efficient volumetric data streaming mechanism. Our results demonstrate the ability of our method to render high quality multiple scattering effects.
    05/2013;
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    ABSTRACT: This paper presents an accurate method to compute the bidirectional reflectance distribution function (BRDF) due to subsurface scattering inside the material of the objects. This computation requires iterating over the different lighting directions, and solving the integro-differential equation of light transport (scattering and absorption). Solving the light transport equation is expensive, and solving it independently for different directions adds even further to the expense. However most of the computations are very similar between directions. We make use of Green's function of the transport problem to have a better separation between computations that are independent of incident directions from those that are dependent. This allows us to avoid as much repetition in the computations as possible, thus gives us a faster BRDF computation method without any loss of accuracy. We validate our method against a standard light transport solver and use it to compute BRDF for a variety of materials.
    05/2013;
  • Ke Chen, Charly Collin, Ajit Hakke-Patil, Sumanta Pattanaik
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    ABSTRACT: Accurately modeling BRDF for real world materials is important and challenging for realistic image synthesis. For a majority of materials most of the incident light enters the material, undergoes multiple scattering under the surface before exiting the material's surface as reflection. Physically correct modeling of such BRDF must take into account of this subsurface volumetric light transport. Most of the accurate numerical solution methods (ex: Monte Carlo, Discrete Ordinate Methods (DOM)) for volumetric light transport compute radiance field for the whole volume, and are expensive. As BRDF ultimately relates only the outgoing radiation field at the boundary to the incident radiation, radiation field computed for the bulk of the material does not provide any useful information and hence the effort involved in computing them can be considered as wasteful. So for efficient BRDF computation any method that allows us to compute the radiance field only at the boundary would be a preferable choice. The search for such a method led us to the Ambartsumian's method [Sobolev 1975; Mishchenko et al. 1999].
    Proceedings of the ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games; 03/2013
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    ABSTRACT: A new method for interactive rendering of complex lighting effects combines two algorithms. The first performs accurate ray tracing in heterogeneous refractive media to compute high-frequency phenomena. The second applies lattice-Boltzmann lighting to account for low-frequency multiple-scattering effects. The two algorithms execute in parallel on modern graphics hardware. This article includes a video animation of the authors' real-time algorithm rendering a variety of scenes.
    IEEE Computer Graphics and Applications 01/2012; 32:34-43. · 1.23 Impact Factor
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    ABSTRACT: In this paper we propose a novel technique to perform real-time rendering of translucent inhomogeneous materials, one of the most well-known problems of computer graphics. The developed technique is based on an adaptive volumetric point sampling, done in a preprocessing stage, which associates to each sample the optical depth for a predefined set of directions. This information is then used by a rendering algorithm that combines the object’s surface rasterization with a ray tracing algorithm, implemented on the graphics processor, to compose the final image. This approach allows us to simulate light scattering phenomena for inhomogeneous isotropic materials in real time with an arbitrary number of light sources. We tested our algorithm by comparing the produced images with the result of ray tracing and showed that the technique is effective. KeywordsRendering-Subsurface scattering-GPU computing
    The Visual Computer 01/2010; 26:583-593. · 0.91 Impact Factor
  • Juraj Obert, Fabio Pellacini, Sumanta N. Pattanaik
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    ABSTRACT: We present an approach for editing shadows in all-frequency lighting environments. To support artistic control, we propose to decouple shadowing from lighting and focus on providing intuitive controls to edit the former. To accomplish this task, we precompute and store scene visibility information separately from lighting and BRDFs and allow artists to edit visibility directly, by providing operations to select shadows and edit their shape. To facilitate a wider range of editing operations, we generalize visibility from binary to three-channel floating point quantities and introduce a novel shadow representation based on computation of visibility ratios between the original render and the edited one. We demonstrate our results for diffuse and glossy surfaces, still scenes and animations.
    Computer Graphics Forum 01/2010; 29:1441-1449. · 1.64 Impact Factor
  • 01/2010; Academic Press., ISBN: 978-0-12-374914-7
  • Kevin Boulanger, Kadi Bouatouch, Sumanta N. Pattanaik
    J. Graphics, GPU, & Game Tools. 01/2010; 15:1-12.
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    Musawir A Shah, Jaakko Konttinen, Sumanta Pattanaik
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    ABSTRACT: The authors present an algorithm for real-time realistic rendering of translucent materials such as marble, wax, and milk. Their method captures subsurface scattering effects while maintaining interactive frame rates. The main idea of this work is that it employs the dipole diffusion model with a splatting approach to evaluate the integral over the surface area for computing illumination due to multiple scattering.
    IEEE Computer Graphics and Applications 03/2009; 29(1):66-78. · 1.23 Impact Factor
  • Kévin Boulanger, Sumanta N Pattanaik, Kadi Bouatouch
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    ABSTRACT: The authors present a real-time grass rendering technique that works for large, arbitrary terrains with dynamic lighting, shadows, and a good parallax effect. A novel combination of geometry and lit volume slices provides accurate, per-pixel lighting. A fast grass-density management scheme allows the rendering of arbitrarily shaped patches of grass.
    IEEE Computer Graphics and Applications 03/2009; 29(1):32-41. · 1.23 Impact Factor
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    ABSTRACT: Smell is a key human sense which can significantly effect our perception of an environment. Although, typically not as developed as our other senses, the presence of a pleasant or unpleasant smell can alter the way we view a scene. Such a cross-modal effect can be substantial with parts of a scene literally going unnoticed as the smell dominates our senses. This paper investigates the cross-modal affect on the perception of the real-time animation of a field of grass in the presence of the smell of cut-grass. Rendering the high level of detail of a close-up view of a field of grass is computationally very demanding. In the real world the smell of grass would be present, and especially strong if the grass had just been cut, for example in preparation for a sports event. By exploiting the cross-modal interaction between smell and visuals we are able to render a lower quality version of a field of grass at a reduced computational cost, without the viewer being aware of the quality difference compared to a high quality version.
    01/2009;
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    ABSTRACT: Abstract In the last few years, researchers in the field of High Dynamic Range (HDR) Imaging have focused on providing tools for expanding Low Dynamic Range (LDR) content for the generation of HDR images due to the growing popularity of HDR in applications, such as photography and rendering via Image-Based Lighting, and the imminent arrival of HDR displays to the consumer market. LDR content expansion is required due to the lack of fast and reliable consumer level HDR capture for still images and videos. Furthermore, LDR content expansion, will allow the re-use of legacy LDR stills, videos and LDR applications created, over the last century and more, to be widely available. The use of certain LDR expansion methods, those that are based on the inversion of Tone Mapping Operators (TMOs), has made it possible to create novel compression algorithms that tackle the problem of the size of HDR content storage, which remains one of the major obstacles to be overcome for the adoption of HDR. These methods are used in conjunction with traditional LDR compression methods and can evolve accordingly. The goal of this report is to provide a comprehensive overview on HDR Imaging, and an in depth review on these emerging topics.
    Computer Graphics Forum 01/2009; 28:2343-2367. · 1.64 Impact Factor
  • K. Boulanger, K. Bouatouch, S. Pattanaik
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    ABSTRACT: High quality lighting is one of the challenges for interactive tree rendering. To this end, this paper presents a lighting model allowing real-time rendering of trees with convincing indirect lighting. Rather than defining an empirical model to mimic lighting of real trees, we work at a lower level by modeling the spatial distribution of leaves and by assigning them probabilistic properties. We focus mainly on precise low-frequency lighting that our eyes are more sensitive to and we add high-frequency details afterwards. The resulting model is efficient and simple to implement on a GPU.
    Computer Graphics Forum 09/2008; 27(4):1189 - 1198. · 1.64 Impact Factor
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    ABSTRACT: New gradients Gradients by [Křivánek et al. 2005] Figure 1: Right: The gradient computation proposed by [Křivánek et al. 2005] does not properly handle significant change of occlusion in the sampled environment and leaves visible interpolation artifacts. Left: The radiance gradient computation proposed in this paper handles occlusion changes and leads to a smoother indirect illumination interpolation on the glossy floor. The two images in the middle are cut out from the two images on the very left and very right. Abstract We describe a new and accurate algorithm for computing transla-tional gradients of incoming radiance in the context of a ray tracing-based global illumination solution. The gradient characterizes how the incoming directional radiance function changes with displace-ment on a surface. We use the gradient for a smoother radiance interpolation over glossy surfaces in the framework of the radi-ance caching algorithm. The proposed algorithm generalizes the irradiance gradient computation by [Ward and Heckbert 1992] to allow its use for non-diffuse, glossy, surfaces. Compared to previ-ous method for radiance gradient computation, the new algorithm yields better gradient estimates in the presence of significant oc-clusion changes in the sampled environment, allowing a smoother indirect illumination interpolation.
    08/2008;
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    ABSTRACT: This article presents a rendering technique for multilayered materials. Unlike existing methods, our technique does not assume that the thickness of these layers is constant. We use relief texture mapping to model a material's interior. Instead of representing the surface details, we use this method to represent the object's inner structure. We describe the material's layers using a simple 2D texture, in which each channel encodes a thickness. Our method supports nonplanar surfaces and falls between subsurface rendering methods based on surfaces and 3D texture-based algorithms. Furthermore, our solution provides a compact way to design translucent objects using a small amount of data.
    IEEE Computer Graphics and Applications 02/2008; · 1.23 Impact Factor
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    ABSTRACT: Thanks to an increase in rendering efficiency, indirect illumination has recently begun to be integrated in cinematic lighting design, an application where physical accuracy is less important than careful control of scene appearance. This paper presents a comprehensive, efficient, and intuitive representation for artistic control of indirect illumination. We encode user's adjustments to indirect lighting as scale and offset coefficients of the transfer operator. We take advantage of the nature of indirect illumination and of the edits themselves to efficiently sample and compress them. A major benefit of this sampled representation, compared to encoding adjustments as procedural shaders, is the renderer-independence. This allowed us to easily implement several tools to produce our final images: an interactive relighting engine to view adjustments, a painting interface to define them, and a final renderer to render high quality results. We demonstrate edits to scenes with diffuse and glossy surfaces and animation.
    Computer Graphics Forum 01/2008; 27:1217-1223. · 1.64 Impact Factor
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    ABSTRACT: d a c b Figure 1: A lighting design session in LightShop. (a) Lighting process starts by placing two spotlights. LightShop instantaneously shows physically-based global illumination solution, which serves as a starting point for applying light transport editing tools. (b) The intensity of the indirect light emitted by the cylindrical object above the staircase is increased using the Light Source Brush. Notice pronounced soft shadows under the staircase and under the table. (c) The contribution of light reflected off the floor is modified by increasing its saturation and intensity with the Caster/Receiver Tool. (d) The Illumination Brush is used to paint indirect illumination on the far end of the wall and on the statue. The adjustments were exaggerated to illustrate achievable effects.
    08/2007;
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    Eric Risser, Musawir Shah, Sumanta N. Pattanaik
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    ABSTRACT: Relief mapping using the secant method offers an efficient method for adding per-pixel displacement based on height fields to an arbitrary polygonal mesh in real time. The technique utilizes an interval-based method in which bounds of the interval are computed in the beginning and are refined at every iteration until the intersection point is reached. The search space defined by the interval reduces and converges to the intersection point rapidly and outperforms the currently popular method based on binary search (relief mapping) used for performing this task. We compute the bounds using a simple ray-segment intersection method. We demonstrate the algorithm and show empirical and explicit evidence of the speed-up. Source code is available online.
    J. Graphics Tools. 01/2007; 12:17-24.

Publication Stats

2k Citations
37.96 Total Impact Points

Institutions

  • 2004–2013
    • University of Central Florida
      • Department of Electrical Engineering & Computer Science
      Orlando, Florida, United States
  • 2009
    • NVIDIA
      Santa Clara, California, United States
  • 2005–2007
    • IRISA - Institut de Recherche en Informatique et Systèmes Aléatoires
      Roazhon, Brittany, France
  • 2005–2006
    • National Institute for Research in Computer Science and Control
      Le Chesney, Île-de-France, France
  • 1996–2000
    • Cornell University
      • Department of Computer Science
      Ithaca, New York, United States