Sun Rays through the trees

Started by bobbystahr, January 29, 2007, 01:55:36 PM

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bobbystahr

Early on in this release someone, I can't recall who, posted an image of visible sun rays thru the trees and mentioned they did it with 'ground fog'. Is that the 'atmosphere' or clouds dropped to the ground. A tute on this would be much appreciated by me for one and I'm sure any number of frusteated members...
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

mrwho

I've got a TGD file from someone at Ashundar.com for ground fog, I'll attach it. Ad for a tutorial, I don't have one readily available, but the TGD file should help

bobbystahr

Many thanx mrwho...will go explore and learn ;D
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

Oshyan

You may be referring to an image by Frank Basinski, although others have since created similar effects. I believe Frank used a low-level, low density cloud layer for this.

- Oshyan

bobbystahr

That may well be him. It was in the first week or so of the release. It was a not very dense forest scene with IIRC the light coming from the top left at maybe a 50 degree angle...it was stunning from my point of view. My problem is getting the correct density setting I guess as I've played with both that and the atmosphere settings to no avail as yet. Will keep on pushin pixels around till I get it then I'll move on to the next windmill, heh heh heh
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

FrankB

Quote from: bobbystahr on January 30, 2007, 12:43:09 AM
That may well be him. It was in the first week or so of the release. It was a not very dense forest scene with IIRC the light coming from the top left at maybe a 50 degree angle...it was stunning from my point of view. My problem is getting the correct density setting I guess as I've played with both that and the atmosphere settings to no avail as yet. Will keep on pushin pixels around till I get it then I'll move on to the next windmill, heh heh heh

Hi,

that was me, indeed. In essence, Oshyan correctly specified that a low hanging cloud layer (3D), probably 30 meters thick, was used for the effect. The settings that are required to get rays are ray traced shadows enabled for the cloud layer. That allows the terrain and other things (like objects) to cast shadows onto the fog. As for the density, try finding the right denstiy so that you can just barely see the "fog". It's best to test that part without ray traced shadows enabled, for performance reasons. In order to get no grain spoil your render, you will need very high samples for the atmosphere, probably around 80-100. Be prepared for an excessively long render, though, as the renderer is not yet optimised for scenes like this.

Good luck,
Frank

bobbystahr

Hiya Frank,
      Cool, that's pretty much what I've arrived at thru trial and error, and Oshyam's input along with what I know of volumetrics from other apps, but I didn't bump the samples up that much so it may be disappointing but then, that's learning. I never make the same mistake twice though, I'm endlessly creative that way, heh heh heh.
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist