Screen Space Meshes
Screen Space Meshes. Mueller, et al. SCA ’07
Mueller, Schirm and Duthaler present a method for constructing a polygonal mesh in screen space from depth information resulting from fluid simulation. By applying a variant of Marching Squares (which is itself a 2D variant of Marching Cubes), they extract the polygonal surface of visible fluid surfaces. By smoothing the depth values before extraction, they produce a smoother fluid surface. Additionally, they discuss “smoothing” the silhouette boundary by iteratively averaging vertex positions along the silhouette. Silhouette locations are typically where SPH methods reveal their nature because of a reduced number of neighboring spheres to smooth. This method reduces the blobby edge effect. I’d be curious to see a video with this silhouette shrinking in action. I would think you would get some flickering or popping effects when spherical elements of the underlying simulation break free of the silhouette.
Overall, I don’t see a clear reason why this method is preferable over a meshless method (besides the silhouette shrinking). Refraction, occlusion and reflection could all be done without a mesh. It is likely possible to shrink the silhouette as described using image processing methods.
Unsmoothed
Smoothed
NPR style of Team Fortress 2
While the gaming world waits patiently for the release of Valve’s Team Fortress 2, Jason Mitchell et al. have been releasing a deluge of material on the rendering style of the game. While there is nothing especially novel about the techniques, I think the paper is an interesting exercise in authoring a lighting model to achieve a desired look. It helps that the trailer videos are fun to watch.
Illustrative Rendering in Team Fortress 2, Mitchell et al. NPAR 2007.
