Rendering clouds with the Mie phase function
Posted 12 August 2012 - 03:53 AM
I've made a detailed writeup on my blog, and there's a demo on vimeo too:
Posted 12 August 2012 - 06:35 AM
Posted 12 August 2012 - 02:08 PM
henyey-greenstein is reasonably simple, perhaps a bit cheaper than to the cost (using this method) of a texture lookup? Probably not by much... To properly calculate the Mie function from scratch is very heavy though - it goes right back to first principles (distribution of droplet sizes) and runs the physics through that. AFAIK it can take something like mieplot on the order of hours to calculate the full 180 degrees..
 (1 - g*g) / pow(1 + g*g - 2*g*costheta, 1.5f);
Posted 12 August 2012 - 03:49 PM
Once you have the data you can just look it up, like you did there, and if you don't care too much about energy conservation you could tweak it (or make it up!) for different materials.
Edited by Macha, 12 August 2012 - 03:49 PM.
Posted 12 August 2012 - 05:13 PM
Posted 13 August 2012 - 07:52 AM
Posted 13 August 2012 - 02:41 PM
Posted 16 August 2012 - 05:07 PM
I was just about to post a related concern about the included physically based phase function, which is that at extreme forward scattering angles it appears to clamp to a fixed value.
Posted 20 August 2012 - 12:19 AM
Very interesting stuff. Were you on Dan B's cloud team at Dr D. I was always very interested in the set up you guys were using.
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