Rendering and animation of gaseous phenomena by combining fast volume and scanline A-buffer techniques

Abstract

This paper describes a new technique that efficiently combines volume rendering and scanline a-buffer techniques. This technique is useful for combining all types of volume-rendered objects with scanline rendered objects and is especially useful for rendering scenes containing gaseous phenomena such as clouds, fog, and smoke. The rendering and animation of these phenomena has been a difficult problem in computer graphics.A new algorithm for realistically modeling and animating gaseous phenomena is presented, providing true three-dimensional volumes of gas. The gases are modeled using turbulent flow based solid texturing to define their geometry and are animated based on turbulent flow simulations. A low albedo illumination model is used that takes into consideration self-shadowing of the volumes.

Volume illustration: nonphotorealistic rendering of volume models

“…4, 15, 17, 19) with volume illustration images (Figs. 5,6,7,8,9,10,11,12,13,14,16,18,20) clearly shows the power of employing volumetric illustration techniques to enhance 3D depth perception and volumetric feature understanding.…”

“…We begin with a volume renderer that implements physics-based illumination of gaseous phenomena and includes volumetric shadowing and self-shadowing [6]. Fig.…”

“…Many volume rendering systems use very simple illumination models and often do not include the effect of shadows, particularly volume self-shadowing to improve performance, even though many volume shadowing algorithms have been developed [6], [17]. Accurate volumetric shadowing often produces subtle effects which do not provide strong threedimensional depth cues.…”

“…Kajiya and von Herzen's original work on volume ray tracing for generating images of clouds [17] incorporated a physics-based illumination and atmospheric attenuation model. This work in realistic volume rendering techniques has been extended by numerous researchers [29], [6], [20], [37], [25], [30]. In contrast, traditional volume rendering has relied on the use of transfer functions from scalar value to rendered opacity to produce artificial views of the data which highlight regions of interest [5].…”

Fast re-rendering of volume and surface graphics by depth, color, and opacity buffering

“…A rendering pipeline that can incorporate the efficiency of polygonally defined objects into the realism of a volumetric scene is desirable, especially in medical applications (Kaufman et al, 1990) (Ebert and Parent, 1990) such as virtual endoscopy surgery simulation (Geiger and Kikinis, 1995). In such a system, sampled volume data, such as CT or MR images can be directly combined with synthetic objects such as surgical instruments, probes, catheters, prostheses and landmarks displayed as glyphs.…”