A technique is presented to compute the reflected illumination from curved mirror surfaces onto other surfaces. In accordance with Fermat's principle, this is equivalent to finding extremal paths from the light source to the visible surface via the mirrors. Once pathways of illumination are found, irradiance is computed from the Gaussian curvature of the geometrical wavefront. Techniques from optics, differential geometry and interval analysis are applied to solve these problems. CR Categories and Subject Descriptions: I.3.3 [ Computer Graphics ]: Picture/Image Generation; I.3.7 [ Computer Graphics ]: Three-Dimensional Graphics and Realism General Terms: Algorithms Additional Keywords and Phrases: Caustics, Differential Geometry, Geometrical Optics, Global Illumination, Interval Arithmetic, Ray Tracing, Wavefronts 1. Introduction Ray tracing provides a straightforward means for synthesizing realistic images on the computer. A scene is first modeled, usually by a collection of implici...

In order to synthesize realistic images of scenes that include water surfaces, the rendering of optical effects caused by waves on the water surface, such as caustics and reflection, is necessary. However, rendering caustics is quite complex and time-consuming. In recent years, the performance of graphics hardware has made significant progress. This fact encourages researchers to study the acceleration of realistic image synthesis. We present here a method for the fast rendering of refractive and reflective caustics due to water surfaces. In the proposed method, an object is expressed by a set of texture mapped slices. We calculate the intensities of the caustics on the object by using the slices and store the intensities as textures. This makes it possible to render caustics at interactive rate by using graphics hardware. Moreover, we render objects that are reflected and refracted due to the water surface by using reflection/refraction mapping of these slices.

Caustics produce beautiful and intriguing illumination patterns. However, their complex behavior make them difficult to simulate accurately in all but the simplest configurations. To capture their appearance, we present an adaptive approach based upon light beams. The coherence between light rays forming a light beam greatly reduces the number of samples required for precise illumination reconstruction. The light beams characterize the distribution of light due to interactions with specular surfaces (specular light flux) in 3D space, thus allowing for the treatment of illumination within single-scattering participating media. The hierarchical structure enclosing the light beams possesses inherent properties to detect efficiently every light beam reaching any 3D point, to adapt itself according to illumination effects in the final image, and to reduce memory consumption via caching.

Abstract. The creation and rendering of realistic water scenes is one of the challenging tasks in Computer Graphics. To reproduce the illumination and colour inside water bodies an algorithm capable of dealing with media with anisotropic and multiple scattering has to be used. We have developed a simulation system based in the discrete ordinates method to solve the problem of light transport in general participating media. We discuss its application to the rendering of images of natural waters, a difficult task due to the different components that determine their optical behaviour. A couple of simple images calculated in different waters are presented. Results indicate the relevant role played by the spectral behaviour of the absorption and scattering coefficients and by the correct treatment of the phase function in the process of image generation.

The creation and rendering of realistic water scenes is one of the challenging tasks in Computer Graphics. To reproduce the illumination and colour inside water bodies an algorithm capable of dealing with media with anisotropic and multiple scattering has to be used. We have chosen the discrete ordinates method to solve the problem of light transport. Both the theoretical basis and the algorithm that has been implemented are described in the paper. A couple of simple images calculated in different waters are presented. Results indicate the relevant role played by the spectral behaviour of the absorption and scattering coefficients in the process of image generation. Keywords Participating Media, Discrete Ordinates, Ocean Optics, Global Illumination. 1.