Non-Photorealistic Smoke

Alex Mohr and Andrew Selle

Simulating and rendering smoke has been studied recently Fedkiw, et. al. in Visual Simulation of Smoke in SIGGRAPH '01. Traditional smoke rendering is based on a line-integral attenuation model in Kajiya and Herzen's Ray Tracing Volume Densitites in SIGGRAPH '84. More complicated approaches involving photon mapping for simulating multiple scattering are also available. However, little has been done for non-photorealistic rendering of smoke. This is an important subject, because sometimes, an animator desires a more stylized look. Therefore, the goal of our project was to use smoke simulation results to render stylized smoke

Below are some of our results. Our project builds on the work of Deussen and Strothotte in Computer-Generated Pen-and-ink Illustration of Trees in SIGGRAPH '00. We used their depth difference thresholding technique to choose when to draw black silhouette lines. To maintain temporal coherency we used a particle tracking scheme that advected particles based on the traditional Navier-Stokes voxel simulation grid. We provided a number of different templates for rendering of the particles.

DivX movies:

We rendered the particles in our simulation using different billboard templates. Here are three different templates and their resulting outputted images.

We also had the ability to color the particles based on the interpolated density of the smoke.