Generalized Image Acquisition and Analysis

Interactive Volume Caustics in Single-Scattering Media

Volume caustics are intricate illumination patterns formed by light first interacting with a specular surface and subsequently being scattered inside a participating medium. Although this phenomenon can be simulated by existing techniques, image synthesis is usually non-trivial and time-consuming. Motivated by interactive applications, we propose a novel volume caustics rendering method for single-scattering participating media. Our method is based on the observation that line rendering of illumination rays into the screen buffer establishes a direct light path between the viewer and the light source. This connection is introduced via a single scattering event for every pixel affected by the line primitive. Since the GPU is a parallel processor, the radiance contributions of these light paths to each of the pixels can be computed and accumulated independently. The implementation of our method is straightforward and we show that it can be seamlessly integrated with existing methods for rendering participating media. We achieve high-quality results at real-time frame rates for large and dynamic scenes containing homogeneous participating media. For inhomogeneous media, our method achieves interactive performance that is close to real-time. Our method is based on a simplified physical model and can thus be used for generating physically plausible previews of expensive lighting simulations quickly.

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Maximum Mipmaps for Fast, Accurate, and Scalable Dynamic Height Field Rendering

Art Tevs, Ivo Ihrke, Hans-Peter Seidel
In: Proceedings of I3D 2008.



Abstract

This paper presents a GPU-based, fast, and accurate dynamic height field rendering technique that scales well to large scale height fields. Current real-time rendering algorithms for dynamic height fields employ approximate ray-height field intersection methods, whereas accurate algorithms require pre-computation in the order of seconds to minutes and are thus not suitable for dynamic height field rendering. We alleviate this problem by using maximum mipmaps, a hierarchical data structure supporting accurate and efficient rendering while simultaneously lowering the pre-computation costs to negligible levels. Furthermore, maximum mipmaps allow for view-dependent level-of-detail rendering. In combination with hierarchical ray-stepping this results in an efficient intersection algorithm for large scale height fields.
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Bibtex

@inproceedings{Tevs08:MMM,
author = {Art Tevs and Ivo Ihrke and Hans-Peter Seidel},
title = {Maximum Mipmaps for Fast, Accurate, and Scalable Dynamic Height Field Rendering},
booktitle = {Symposium on Interactive 3D Graphics and Games (i3D'08)},
year = 2008,
pages = {183--190},
}
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