2 ms·

As someone who enjoys making atmospheric simulation renderings (http://www.indigorenderer.com/images/clouds-0 http://www.indigorenderer.com/images/clouds-0), th

• AceJohnny2 12y ago
  How're you rendering the clouds? A friend of mine did a thesis a few years ago on real-time cloud rendering [1]. It was very interesting learning about cloud transference functions (and what a Glory is!) and how they found a way to optimize that into a manageable database (IIRC) usable for real-time and realistic rendering. [1] http://www-evasion.imag.fr/Publications/2008/BN08a/ http://www-evasion.imag.fr/Publications/2008/BN08a/
  • Ono-Sendai 12y ago
    The clouds are done with multiple-scattering path-tracing with participating media. Basically the ray bounces around inside the cloud until it exits :) The cloud density is defined by a shader, which basically takes the form of a function from position to density (scattering coefficient).
    • AceJohnny2 12y ago
      Sounds like you're taking the brute-force approach, and the aforementioned thesis could show how to improve that. The powerpoint is surprisingly clear, IMHO. From the paper's conclusion: "We propose a new approach to find significant light paths in clouds via searching for their collector area which comprises their entry point on the lit surface of the cloud. In addition to this new formulation we have proposed a new, GPU-based algorithm to find these collectors and compute their contributions in interactive time. Similarly to our previous model, we account for the varying anisotropy of light transport by treating separately light paths of different orders." Of course, that's avoiding assumptions about how easy it is to integrate in your rendering... ;)