Grainy Atmosphere

Started by dhavalmistry, January 20, 2007, 10:44:19 am

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dhavalmistry

Hi, I rendered this with very High settings for atmosphere but I am still getting grains

128 samples of atmosphere and it took 32 Hrs to render  :'(

All I wanna know is why is there grains near sun and godrays at middle-centre of the image....

thanx..
"His blood-terragen level is 99.99%...he is definitely drunk on Terragen!"

oggyb

We're told in other threads that it's not uncommon to need 256 or even 512 samples for nice godrays.  Unless there's anothing setting that can take care of it that I don't know about, that's my tuppence worth.

M.

Oshyan

Actually 256-512 was probably recommended for *clouds*, not atmosphere. 128 is usually the highest I'd recommend for atmosphere but yes occasionally more is needed, particularly when "godrays" are involved. One thing that's causing high render times here is the interaction between high atmosphere samples and reflections on the water. So you might consider rendering most of the image with lower atmosphere samples (or rather just keeping the version you've already created), then use a crop render to render only the part that is still noisy with higher samples. This will cut down on render time dramatically by avoiding the re-rendering of reflections.

- Oshyan

Cyber-Angel

Would it be possible in the future to have the renderer only re-render those elements of a scene that have changed rather that recalculate to whole image, this would have to be conditional on the camera position remaining the same other wise then yes re-rendering the whole scene would have to be done.

Maybe there is a reason you cannot do this, I don't know, but just having the renderer some how only re-render that which has changed seems like the way to move forward; I remember a similar request for Bryce many moons ago but it never got implemented for one reason or another.

Regards to you.

Cyber-Angel

Oshyan

In many cases even a seemingly small change will actually affect the entire render, if not necessarily in a visible way. In this case the atmosphere samples change *would* affect the entire render and such a system would be useless. Although there are situations where it could save a lot of time, actually implementing it could be very difficult, especially given the effects of Global Illumination. If it ever were to be implemented it seems like an advanced feature that would not be seen until later releases, TG3 perhaps.

- Oshyan

Cyber-Angel

He He TG3 still many, many moons away still lots of cool things to come between now and then; time to start raiding the littriture.

Regrads to you.

Cyber-Angel