Some clouds + tgd + thoughts on RTA rendersettings *v3*

Tangled-Universe · May 16, 2011, 03:36:43 AM

Just before I went to bed I had to do some clouds for an overnight render...
Nothing really special, but still kinda liked the warped edges and detail.
I have included the .tgd for the interested.

Cheers,
Martin

swissAdA · May 16, 2011, 05:51:36 AM

Looks Nice . Thank You!

Tangled-Universe · May 16, 2011, 07:38:15 AM

Thanks, and you're welcome

For everyone who's using this:

The AA is set @ 4 and ray traced atmosphere is enabled.
This means that the quality of cloud rendering is not dependent on the combination render detail + cloud quality anymore, but rather AA# and cloud quality.
You still might consider using higher render detail levels, since the GI settings are being multiplied with that setting.
However, raytraced atmosphere often is quicker and gives better results.

Since I had all the time to render I chose to render it with 100 samples = quality 1.
The speed/quality ratio is low with these settings.
A similar but much quicker result can be obtained with about half the samples, if not even less.

If you decide to use these (or other) clouds with AA6 or AA8 then reduce samples even further.
For AA6 I had nice results with 16 samples = 0.16 quality.
For AA8 you might even consider ~8 samples = 0.05 quality. Yes, 0.08 quality!

For instance, if you have models in your scene you'll need AA>4 for nice rendering of your models.
Then lower cloud/atmo samples accordingly to keep things fast.
I'll prepare an example and post it soon here.

Cheers,
Martin

Henry Blewer · May 16, 2011, 07:47:49 AM

That is interesting. I have been using 24 samples for the atmosphere RT, and 0.65 for the cloud/s detail. Being able to reduce the atmosphere samples with higher AA would save lots of time.

Tangled-Universe · May 16, 2011, 08:56:58 AM

Quote from: njeneb on May 16, 2011, 07:47:49 AM
That is interesting. I have been using 24 samples for the atmosphere RT, and 0.65 for the cloud/s detail. Being able to reduce the atmosphere samples with higher AA would save lots of time.

24 samples for the atmosphere RT.
I "know" that this is OK since it is very unlikely you'll render with AA1. If you did, it wouldn't be sufficient, likely.
It's similar to saying "my clouds look noisy, although I use 200 samples" without knowing the detail equivalence when not using RTA.
In the future documentation these relationships should be worked out very well, since there's been a lot of confusion about it and more confusion will be created with RTA introduced.

It's pretty complicated already and I/others haven't even mentioned that you can also play with the pixel sampler settings to affect RTA rendertimes.
That makes it potentially even more complicated.

Tangled-Universe · May 16, 2011, 08:59:45 AM

Here's a small comparison chart.
The rendersettings were like in the TGD posted above, except that AA was increased from 4 to 6.

As you can see it is possible to render smooth clouds with insane low cloud detail/samples.
Quality 0.16-0.24 is already sufficient in this particular case and increasing further doesn't have very significant improvement.
Only significant increase in rendertime.`

! EDIT: the last picture to the right has 48 samples = 0.48 cloud quality as settings. Sorry!

inkydigit · May 16, 2011, 10:01:58 AM

cheers martin, this will be useful...

efflux · May 16, 2011, 05:00:23 PM

Those are great clouds. Better than usual TG2 clouds.

Henry Blewer · May 16, 2011, 05:54:40 PM

A picture is worth a thousand words. I saved the image. It will be quite useful for quick reference.

Hetzen · May 16, 2011, 05:59:34 PM

Those AA settings are very interesting Martin. I guess the last image is 32 samples?

I didn't realise there was that much connection with AA over Cloud Quality with RTA. That said there is a difference with the last two in your sequence of 4, but as you say it's minimal.

I've not downloaded your TGD, but I'm guessing there's a warp in there. Funny, I was looking up when I should have been looking forward on the M25, noticing the same effect you're trying to simulate. I wonder if you could use your clouds as a mask on a dense ridges/warped noise?

jbest · May 16, 2011, 06:08:57 PM

Interesting. The clouds kind of look like someone painted them. They do look realistic though.

Tangled-Universe · May 17, 2011, 04:25:44 AM

Quote from: Hetzen on May 16, 2011, 05:59:34 PM
Those AA settings are very interesting Martin. I guess the last image is 32 samples?

I didn't realise there was that much connection with AA over Cloud Quality with RTA. That said there is a difference with the last two in your sequence of 4, but as you say it's minimal.

I've not downloaded your TGD, but I'm guessing there's a warp in there. Funny, I was looking up when I should have been looking forward on the M25, noticing the same effect you're trying to simulate. I wonder if you could use your clouds as a mask on a dense ridges/warped noise?

Hi Jon, no the last picture has 48 samples. 32 would have been logical, but I wanted to show 48 samples without having to render 2 more 8-sample-increments as well.
I'm planning to show a test with AA2 vs 4 vs 6, but I have to think about it how to make that as clear as possible.

Sure you can also use the main cloud as a blend for ridged warped noise and mix these in.
A small drawback is that it will be mixed in the whole cloud and not the edges only.
With a warp shader and a small scale powerfractal as warper you can get these effects at the edges only.

freelancah · May 17, 2011, 04:39:48 AM

Very interesting tests. This gives me some ideas to experiment with!

Tangled-Universe · May 28, 2011, 04:53:57 AM

Had another one with the .tgd posted above:

Hetzen · May 28, 2011, 02:33:49 PM

You've got less paint streaks in that one Martin. More refined than your last.

I don't know if you're familiar with The Orb's - Little fluffy clouds track, I heard a great re-version of it to the typical english weather...

http://www.youtube.com/watch?v=h2qSvqrCNEk