VMV12

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https://diglib.eg.org/handle/10.2312/1016

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Browsing VMV12 by Subject "Color"

Now showing 1 - 4 of 4
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    Fast Accurate Soft Shadows with Adaptive Light Source Sampling
    (The Eurographics Association, 2012) Schwärzler, Michael; Mattausch, Oliver; Scherzer, Daniel; Wimmer, Michael; Michael Goesele and Thorsten Grosch and Holger Theisel and Klaus Toennies and Bernhard Preim
    Physically accurate soft shadows in 3D applications can be simulated by taking multiple samples from all over the area light source and accumulating them. Due to the unpredictability of the size of the penumbra regions, the required sampling density has to be high in order to guarantee smooth shadow transitions in all cases. Hence, several hundreds of shadow maps have to be evaluated in any scene configuration, making the process computationally expensive. Thus, we suggest an adaptive light source subdivision approach to select the sampling points adaptively. The main idea is to start with a few samples on the area light, evaluating there differences using hardware occlusion queries, and adding more sampling points if necessary. Our method is capable of selecting and rendering only the samples which contribute to an improved shadow quality, and hence generate shadows of comparable quality and accuracy. Even though additional calculation time is needed for the comparison step, this method saves valuable rendering time and achieves interactive to real-time frame rates in many cases where a brute force sampling method does not.
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    GPU-accelerated Interactive Material Aging
    (The Eurographics Association, 2012) Günther, Tobias; Rohmer, Kai; Grosch, Thorsten; Michael Goesele and Thorsten Grosch and Holger Theisel and Klaus Toennies and Bernhard Preim
    A photorealistic appearance of a 3D scene is required in many applications today. Thereby, one vital aspect is the usage of realistic materials, for which a broad variety of reflectance models is available. When directly employing those models, surfaces always look new, which contrasts strongly the real objects surrounding us as they have undergone diverse kinds of aging processes. The literature already proposes a set of viable methods to simulate different aging phenomena, but all of them are computationally expensive and can thus only be computed off-line. Therefore, this paper presents the first interactive, GPU-accelerated method to simulate material aging in a given scene. Thereby, our approach allows artists to precisely control the course of the aging process. Our particlebased method is capable to reproduce the most common deterioration phenomena in a few seconds, including plausible dirt bleeding, flow effects, corrosion and patina.
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    Illumination-Driven Opacity Modulation for Expressive Volume Rendering
    (The Eurographics Association, 2012) Csébfalvi, Balázs; Tóth, Balázs; Bruckner, Stefan; Gröller, Eduard; Michael Goesele and Thorsten Grosch and Holger Theisel and Klaus Toennies and Bernhard Preim
    Using classical volume visualization, typically a couple of isosurface layers are rendered semi-transparently to show the internal structures contained in the data. However, the opacity transfer function is often difficult to specify such that all the isosurfaces are of high contrast and sufficiently perceivable. In this paper, we propose a volumerendering technique which ensures that the different layers contribute to fairly different regions of the image space. Since the overlapping between the effected regions is reduced, an outer translucent isosurface does not decrease significantly the contrast of a partially hidden inner isosurface. Therefore, the layers of the data become visually well separated. Traditional transfer functions assign color and opacity values to the voxels depending on the density and the gradient. In contrast, we assign also different illumination directions to different materials, and modulate the opacities view-dependently based on the surface normals and the directions of the light sources, which are fixed to the viewing angle. We will demonstrate that this model allows an expressive visualization of volumetric data.
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    Screen Space Spherical Harmonic Occlusion
    (The Eurographics Association, 2012) Herholz, Sebastian; Schairer, Timo; Schilling, Andreas; Straßer, Wolfgang; Michael Goesele and Thorsten Grosch and Holger Theisel and Klaus Toennies and Bernhard Preim
    In this paper we present a new algorithm for real-time directional occlusion sampling. We combine the real-time capabilities of Screen Space Ambient Occlusion (SSAO) with the Spherical Harmonics (SH) representation of local directional occlusion. SH are well established and used in modern off-line rendering implementations such as PantaRay [PFHA10]. Through our combination we are able to transfer a method for realistic local directional occlusion effects from offline rendering to dynamic real-time applications. These local occlusion effects react to the environmental lighting situation and lead to dynamic and colored local occlusion shadows while only generating a small computational overhead compared to SSAO. Unlike other real-time directional occlusion algorithms such as Screen Space Direction Occlusion (SSDO) [RGS09] our occlusion sampling is separated from the actual lighting process and therefore can be easily integrated in existing SH lighting methods such as Irradiance Volumes [GSHG98]. We furthermore extend our algorithm to include first bounce indirect illumination effects.