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Global Illumination using Photon Maps
, 1996
"... This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy ..."
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Cited by 275 (9 self)
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This paper presents a two pass global illumination method based on the concept of photon maps. It represents a significant improvement of a previously described approach both with respect to speed, accuracy and versatility. In the first pass two photon maps are created by emitting packets of energy (photons) from the light sources and storing these as they hit surfaces within the scene. We use one high resolution caustics photon map to render caustics that are visualized directly and one low resolution photon map that is used during the rendering step. The scene is rendered using a distribution ray tracing algorithm optimized by using the information in the photon maps. Shadow photons are used to render shadows more efficiently and the directional information in the photon map is used to generate optimized sampling directions and to limit the recursion in the distribution ray tracer by providing an estimate of the radiance on all surfaces with the exception of specular...
Tracing Ray Differentials
, 1999
"... Antialiasing of ray traced images is typically performed by supersampling the image plane. While this type of filtering works well for many algorithms, it is much more efficient to perform filtering locally on a surface for algorithms such as texture mapping. In order to perform this type of filteri ..."
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Cited by 88 (0 self)
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Antialiasing of ray traced images is typically performed by supersampling the image plane. While this type of filtering works well for many algorithms, it is much more efficient to perform filtering locally on a surface for algorithms such as texture mapping. In order to perform this type of filtering, one must not only trace the ray passing through the pixel, but also have some approximation of the distance to neighboring rays hitting the surface (i.e., a ray's footprint). In this paper, we present a fast, simple, robust scheme for tracking such a quantity based on ray differentials, derivatives of the ray with respect to the image plane. CR Categories and Subject Descriptors: I.3.7 [Computer Graphics]: ThreeDimensional Graphics and Realism  color, shading, shadowing, and texture; raytracing. 1 INTRODUCTION Ray tracing [18] is an image generation technique that is able to accurately model many phenomena which are difficult or impossible to produce with a traditional graphics pip...
Global illumination using local linear density estimation
 Proceedings of SIGGRAPH 97
, 1997
"... This article presents the density estimation framework for generating viewindependent global illumination solutions. It works by probabilistically simulating the light flow in an environment with light particles that trace random walks originating at luminaires and then using statistical density es ..."
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Cited by 55 (6 self)
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This article presents the density estimation framework for generating viewindependent global illumination solutions. It works by probabilistically simulating the light flow in an environment with light particles that trace random walks originating at luminaires and then using statistical density estimation techniques to reconstruct the lighting on each surface. By splitting the computation into separate transport and reconstruction stages, we gain many advantages including reduced memory usage, the ability to simulate nondiffuse transport, and natural parallelism. Solutions to several theoretical and practical difficulties in implementing this framework are also described. Light sources that vary spectrally and directionally are integrated into a spectral particle tracer using nonuniform rejection. A new local linear density estimation technique eliminates boundary bias and extends to arbitrary polygons. A mesh decimation algorithm with perceptual calibration is introduced to simplify the Gouraudshaded
Rendering Caustics on NonLambertian Surfaces
 Computer Graphics Forum
, 1996
"... This paper presents a new technique for rendering caustics on nonLambertian surfaces. The method is based on an extension of the photon map which removes previous restrictions limiting the usage to Lambertian surfaces. We add information about the incoming direction to the photons and this allows u ..."
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Cited by 42 (3 self)
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This paper presents a new technique for rendering caustics on nonLambertian surfaces. The method is based on an extension of the photon map which removes previous restrictions limiting the usage to Lambertian surfaces. We add information about the incoming direction to the photons and this allows us to combine the photon map with arbitrary reflectance functions. Furthermore we introduce balancing of the photon map which not only reduces the memory requirements but also significantly reduces the rendering time. We have used the method to render caustics on surfaces with reflectance functions varying from Lambertian to glossy specular. Keywords: Caustics, Photon Map, Ray Tracing, Rendering. 1 Introduction Caustics provides some of the most spectacular patterns of light in nature. Caustics are formed when light reflected from or transmitted through a specular surfaces strikes a diffuse surface. An example is the caustic formed as light shines through a glass of wine onto a table. In ...
Eikonal rendering: efficient light transport in refractive objects
 ACM Transactions on Graphics
, 2007
"... Figure 1: Realtime renderings of complex refractive objects – (left) glass with red wine casting a colorful caustic, 24.8 fps. (middle) Amberlike bunny with black embeddings showing anisotropic scattering and volume caustics in the surrounding smoke and its interior, 13.0 fps. (right) Rounded cube ..."
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Cited by 40 (6 self)
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Figure 1: Realtime renderings of complex refractive objects – (left) glass with red wine casting a colorful caustic, 24.8 fps. (middle) Amberlike bunny with black embeddings showing anisotropic scattering and volume caustics in the surrounding smoke and its interior, 13.0 fps. (right) Rounded cube composed of three differently colored and differently refracting kinds of glass showing scattering effects and caustics in its interior, 6.4 fps. We present a new method for realtime rendering of sophisticated lighting effects in and around refractive objects. It enables us to realistically display refractive objects with complex material properties, such as arbitrarily varying refractive index, inhomogeneous attenuation, as well as spatiallyvarying anisotropic scattering and reflectance properties. Usercontrolled changes of lighting positions only require a few seconds of update time. Our method is based on a set of ordinary differential equations derived from the eikonal equation, the main postulate of geometric optics. This set of equations allows for fast casting of bent light rays with the complexity of a particle tracer. Based on this concept, we also propose an efficient light propagation technique using adaptive wavefront tracing. Efficient GPU implementations for our algorithmic concepts enable us to render a combination of visual effects that were previously not reproducible in realtime.
RealTime Caustics
, 2003
"... We present a new algorithm to render caustics. The algorithm discretizes the specular surfaces into sample points. Each of the sample points is treated as a pinhole camera that projects an image of the incoming light onto the diffuse receiver surfaces. Antialiasing is performed by considering the ..."
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Cited by 36 (0 self)
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We present a new algorithm to render caustics. The algorithm discretizes the specular surfaces into sample points. Each of the sample points is treated as a pinhole camera that projects an image of the incoming light onto the diffuse receiver surfaces. Antialiasing is performed by considering the local surface curvature at the sample points to filter the projected images. The algorithm can be implemented using programmable texture mapping hardware. It allows to render caustics in fully dynamic scenes in realtime on current PC hardware.
Global Illumination via DensityEstimation
 Proceedings of 6th Workshop on Rendering (Dublin
, 1995
"... This paper presents a new method for the production of viewindependent global illumination solutions of complex static environments. A key innovation of this new approach is its decomposition of the problem into a loosely coupled sequence of simple modules. This approach decouples the global energy ..."
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Cited by 24 (0 self)
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This paper presents a new method for the production of viewindependent global illumination solutions of complex static environments. A key innovation of this new approach is its decomposition of the problem into a loosely coupled sequence of simple modules. This approach decouples the global energy transport computation from the construction of the displayable shaded representation of the environment. This decoupling eliminates many constraints of previous global illuminationapproaches, yieldingaccurate solutions for environments with nondiffuse surfaces and high geometric complexity. Our algorithm produces a viewindependent display mesh that represents the irradiances on surfaces in a form that allows direct display of the shaded surface. Most traditional radiosity algorithms also use a computational mesh to represent intermediate results in the light transport calculation (e.g., the piecewiseconstant global solution of Smits et al. [17]). Typically, a single representation is used for both the computational and display meshes (e.g. the static mesh used by Neumann et al. [11] and the adaptive mesh used by Teller et al. [18]). Very few display mesh solutions have been produced for environments with more than a few thousand initial surfaces. The only implementation we are aware of that has produced a display mesh for more than 10,000 initial surfaces is the system by Teller et al. [18], which was run on a model with approximately 40,000 initial surfaces. Teller et al. argue that the reason for these surprisingly small limits is the high memory overhead of the data structures associated with the computational mesh. To solve this problem, we draw on an observation by Lischinski et al. [10], that the computational mesh and the display mesh have different purposes and ch...
Path Differentials and Applications
 In Rendering Techniques 2001: 12th Eurographics Workshop on Rendering
, 2001
"... Photorealistic rendering algorithms such as Monte Carlo ray tracing sample individual paths to compute images. Noise and aliasing artefacts are usually reduced by supersampling. Knowledge about the neighborhood of the path, such as an estimated footprint, can be used to reduce these artefacts wi ..."
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Cited by 21 (0 self)
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Photorealistic rendering algorithms such as Monte Carlo ray tracing sample individual paths to compute images. Noise and aliasing artefacts are usually reduced by supersampling. Knowledge about the neighborhood of the path, such as an estimated footprint, can be used to reduce these artefacts without having to trace additional paths. The recently introduced ray differentials estimate such a footprint for classical ray tracing, by computing ray derivatives with respect to the image plane. The footprint proves to be useful for filtering textures locally on surfaces. In this paper, we generalize the use of these derivatives to arbitrary path sampling, including general reflection and refraction functions.
Interactive ScreenSpace Accurate Photon Tracing on GPUs
 EUROGRAPHICS SYMPOSIUM ON RENDERING, TOMAS AKENINEMÖLLER AND WOLFGANG HEIDRICH (EDITORS)
, 2006
"... Recent advances in algorithms and graphics hardware have opened the possibility to render caustics at interactive rates on commodity PCs. This paper extends on this work in that it presents a new method to directly render caustics on complex objects, to compute one or several refractions at such obj ..."
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Cited by 20 (2 self)
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Recent advances in algorithms and graphics hardware have opened the possibility to render caustics at interactive rates on commodity PCs. This paper extends on this work in that it presents a new method to directly render caustics on complex objects, to compute one or several refractions at such objects and to simulate caustics shadowing. At the core of our method is the idea to avoid the construction of photon maps by tracing photons in screenspace on programmable graphics hardware. Our algorithm is based on the rasterization of photon paths into texture maps. Intersection events are then resolved on a perfragment basis using layered depth images. To correctly spread photon energy in screenspace we render aligned point sprites at the diffuse receivers where photons terminate. As our method does neither require any preprocessing nor an intermediate radiance representation it can efficiently deal with dynamic scenery and scenery that is modified, or even created on the GPU.