Optimising Render Settings for Easy Cloud

Started by penboack, January 07, 2017, 11:33:03 AM

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penboack

What is the best way to optimise the rendering of EasyCloud clouds?
I have been working on a scene and have made some test renders which I have posted below, but I am struggling to understand how to get the best result without unnecessarily long render times.
My starting point was the recommendations in the thread http://forums.planetside.co.uk/index.php?topic=6442.0
In the examples below all renders used the Render > Render Quality > Anti-aliasing 12, this setting was optimised for the populations of Xfrog plants.
Figures for settings in parentheses are the prior setting (to remind me what I was using previously).

Render Test 1:
[attachimg=1]
Atmosphere > Quality > Samples 64
Easy Cloud > Quality > Quality 0.75
Render > Quality > Micropoly Detail 0.8
Render time 00:04:14.
The default EasyCloud > Quality > Quality setting. The result is too noisy.

Render Test 2:
[attachimg=1]
Atmosphere > Quality > Samples 64
Easy Cloud > Quality > 1.0
Render > Quality > Micropoly Detail 0.8
Render time 00:04:59.
Little improvement after increasing the EasyCloud > Quality settings from 0.75 to 1.0. The result is too noisy.

Render Test 3:
[attachimg=3]
Atmosphere > Quality > Samples 64
Easy Cloud > Quality > 1.0
Render > Quality > Micropoly Detail 1.0
Render tie 00:06:14.
Increased the Render node Render > Quality > Micropoly Detail setting from 0.8 to 1.0
I actually made a final render with these settings at 2000 x 1000, I was unhappy with the result, there is still too much noise in the clouds.
[attach=7]

Render Test 4:
[attachimg=4]
Atmosphere > Quality > Samples 64
Easy Cloud > Quality > 2.0
Render > Quality > Micropoly Detail 1.0
Render time 00:12:13.
The render is much better, but the render time has doubled.
If the Easy Cloud > Quality setting often needs to be set to 2 to eliminate noise then perhaps the slider needs to be altered in a future update to have a wider range, currently the maximum setting is 1.

Render Test 5:
[attachimg=5]
Atmosphere > Quality > Samples 32 (64)
Easy Cloud > Quality > 2.0
Render > Quality > Micropoly Detail 1.0
Render time 00:10:59.
No change, which is not surprising, as the cloud quality is likely to be determined by the Easy Cloud Quality settings rather than the atmosphere samples.

Render Test 6:
[attachimg=6]:
Atmosphere > Quality > Samples 32
Easy Cloud > Quality > 2.0
Render > Quality > Micropoly Detail 0.8 (1.0)
Render time 00:08:23.
Decreasing the Render > Quality > Micropoly Detail made little difference, but speeded up the render.

What does the Easy Cloud > Quality > Sample jitter setting do, when might I need to change it?
What does the Easy Cloud > Quality > Smallest Scale setting do, when might I need to optimise it?

paq

#1
Hello,

Most of the time I find default Terragen settings working very well (for me) :

So :

- make sure Defer atmo/cloud is activated in the render quality settings.
- Reduce atmosphere sample to 16, and easy cloud setting to default value.

Now to reduce the noise in cloud/atmosphere, increase AA.

Default 2 is a pretty low value, 4 should give a very decent result ... I rarely go over 5.

Probably not the shortest rendertime,  but it's easy to setup :)
Gameloft

Oshyan

Unfortunately that reference thread on render settings is quite old now and does not deal with the newer Defer Atmosphere option, nor does it apply well to Terragen 4 "v3" cloud shading.

The biggest question about your settings, which you haven't answered in any of the examples, is whether Defer Atmo was enabled. If it is, then I'm surprised by the high noise results. If it's not, then I would suggest first enabling it. Then we can work on good settings to optimize for quality vs. render time.

When Defer Atmo is enabled, the main Micropoly Detail setting does not affect cloud quality, it is only then affecting terrain detail. I would not recommend using above 0.65 or .7 (and I often use 0.5, especially if most of the terrain is covered by objects/plants).

Also, even with Defer Atmo disabled, such high atmosphere samples are almost never necessary in situations where the sky is so normally and brightly lit. Higher atmo samples are generally only important for reducing noise when there are heavy shadows in the scene, or the sun is near the horizon. With Defer Atmo enabled, the atmo samples can be even less. When using high AA values of e.g. 12, you can especially reduce atmo samples to even as low as 8 or 6! Even 16 will almost guarantee minimal noise *from the atmosphere* (remember, this is separate from cloud noise), assuming you are using high enough AA. So I would strongly suggest reducing your atmosphere samples as you'll save notable render time.

Once Defer Atmo is enabled it is the antialiasing settings that have the biggest impact on noise levels. I generally recommend cloud Quality values between 1 and 2, and to use the AA settings to optimize noise levels further. I do not suggest going above 3 for Quality if possible. Again you can usually get the noise reduction you need from AA changes.

The main trick with reducing render time when using high AA values (in cases where it is necessary to get good quality vegetation, for example) is to use highly adaptive AA. This can be adjusted in the Edit Sampling dialog, where you can change to e.g. 1/64 first samples, and then adjust the noise threshold to get a good compromise of quality and render time.

- Oshyan

penboack

Thanks for your suggestions they are proving very helpful.

The Defer Atmosphere option was set to off (I started the scene in TG 3.4, where it is off by default).
I followed Oshyan's advice and lowered the Micropoly Detail from 0.8 to 0.6, the terrain is covered in plants.

I have made some more test renders of the clouds, the settings I used and the resulting images below.
I'm afraid that the settings are quite detailed, they are straight out of my notes. The second line of tests 2 and 3 gives the changed parameter.

Render Test 1 snb1208.
Cloud Render Region Benchmark
[attachimg=1]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 6
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.05 (Default 0.05)
Render Time 00:12:03 (00:12:27 including updating the populators)

Render Test 2 snb1208.
Cloud Render Region AA12 (6)
[attachimg=2]
Atmosphere > Quality > Number of Samples 16 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:41:57

Render Test 3 snb1208.
Cloud Render Region AA12, Atmosphere > Quality > Number of Samples 8 (16)
[attachimg=3]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:40:33

To get the Xfrog plants to render with minimal noise seems to require AA12 (AA16 is even better and slower!), which is why I have used that setting for the Cloud Region for testing.
I am working on some tests using the Crop region on the forest close to the shore.
My initial thought is to try using Adaptive Sampling with the First Sampling Level set to 1/16 and to then adjust the Pixel Noise Threshold to see if I can speed up the render of the clouds whilst keeping the detail in the forest.

Would another possibility be to lower the cloud quality, as the Anti-aliasing is very high for the Xfrog objects?

Matt

Yes, this is a difficult case where you need AA high for the trees but it's overkill for the sky. If you can, break the render into two parts. I'm working on ideas to optimise this kind of situation.

Quote from: penboack on January 10, 2017, 03:16:38 PM
Would another possibility be to lower the cloud quality, as the Anti-aliasing is very high for the Xfrog objects?

Yes. With such high AA you should be able to reduce the cloud quality, but I would stay above 0.2. However, when going with a high-noise/high-AA strategy like this the adaptive AA doesn't work as well as I'd like, even with a very low pixel noise threshold setting. So, if you reduce the cloud quality I would keep the adaptive first sampling level at 1/4 or 1/16, but no more extreme than that. It's a tough balancing act that I'm trying to figure out how to work more automatically in future.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Oshyan

I would still also suggest trying highly adaptive AA (with default noise threshold to start) with higher AA levels. I'm surprised I did not see a test for that. For example, AA12, 1/64 first samples, 0.025 noise threshold. As Matt says it does not work as well as it could, but it might help. And if the results look fairly noise-free (due to still such high AA/samples), try increasing the noise threshold a bit...

- Oshyan

penboack

#6
Thanks Matt, Oshyan.

More render tests.
First, Cloud Quality.

Render Test 6 snb1208.
Cloud Render Region AA12, Atmosphere > Quality > Number of Samples 8, EasyCloud > Quality > Quality 0.5 (1)
[attachimg=1]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 0.5 (1)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:30:38
Render time is around 25% shorter when the Cloud Quality setting is reduced from 1 to 0.5.
The amount of Noise in the cloud is increased a little, but is less than that in the Render Test 1 Benchmark render with AA6.

Render Test 7 snb1208.
Cloud Render Region AA12, Atmosphere > Quality > Number of Samples 8, EasyCloud > Quality > Quality 0.25 (0.5)
[attachimg=2]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 0.25 (1)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:21:21
Render time around 50% shorter when the Cloud Quality setting is reduced from 1 to 0.25.
The amount of Noise in the cloud is increased a little over the previous test, but is less than that in the Render Test 1 Benchmark render with AA6.


Second, Cloud Adaptive AA tests.

Render Test 8, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/16 (Default 1/4) first samples.
[attachimg=3]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:26:25
Adaptive sampling is much faster with only fractionally more noise.

Render Test 9, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/64 (1/16) first samples.
[attachimg=4]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/64 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:24:17
Small improvement in the render time compared to the previous test. No real change in the noise level.


Third, Forest Adaptive AA tests

Forest Render Region from 4000 x 2000 Image
Forest Benchmark Render
[attachimg=5]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:08:22.

Render Test 5 snb1208.
Forest Render Region from 4000 x 2000 Image
AA6 (12)
[attachimg=6]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:03:27
Very grainy.

Render Test 10, Adaptive Sampling.
Forest Render Region from 4000 x 2000 Image, First Sampling Level 1/16 (Default 1/4) first samples.
[attachimg=7]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:07:24
The Forest has much more Noise than with the default sampling settings.

Render Test 11, Adaptive Sampling.
Forest Render Region from 4000 x 2000 Image, First Sampling Level 1/16 (Default 1/4) first samples, Pixel Noise Threshold 0.020 (Prior 0.025, Default 0.025)
[attachimg=8]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.020 (Default 0.025)
Render Time 00:09:32
The Forest has more Noise than with the default sampling settings.

Render Test 12, Adaptive Sampling.
Forest Render Region from 4000 x 2000 Image, First Sampling Level 1/16 (Default 1/4) first samples, Pixel Noise Threshold 0.015 (Prior 0.020, Default 0.025)
[attachimg=9]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.015 (Default 0.025)
Render Time 00:12:23
The Forest now has slightly less noise than with the default sampling settings.


Forth, Cloud test with Adaptive AA optimised for the forest to give the same quality as the default AA12 settings

Render Test 13, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/64 (1/64) first samples, Pixel Noise Threshold 0.015 (Default 0.025)
[attachimg=10]
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/64 (Default 1/4) first samples
Pixel Noise Threshold 0.015 (Default 0.025)
Render Time 00:53:24
Render Test with the Adaptive Sampling optimised for the forest.
I forgot to put the First Sampling Level setting back to 1/16, the setting that I was using for the forest, but I am really only interested in the render time here and it would be longer if the setting had been set to 1/16 first samples.
The render time is significantly longer than the default adaptive sampling setting.


Conclusion:
Overall for this scene reducing the Cloud Quality to compensate for the high Anti-aliasing setting that is needed to get a clean render of the forest seems to work best.

Thanks again for your help with optimising the render settings.

Charles

Oshyan

#7
Great to see a lot of tests of this. However I see some confusing results that make me wonder if you're reporting your test parameters correctly in all cases. For example in this test
"Render Test 5 snb1208.
Forest Render Region from 4000 x 2000 Image
AA6 (12)"
You actually list the AA as 12 still. I assumed the parentheses here indicated 12 was the default, but 6 was the current value. Was it 12, or 6?

I'm also a little surprised how you have AA of 12 with default 1/4 sampling and end up with a longer render time with more adaptive AA just by slightly decreasing the noise threshold. Theoretically this is possible, of course, but I think what it mostly shows is that the atmosphere is pretty "undersampled" in your tree area, so no matter the sampling adaptivity, a decrease in noise threshold means more samples are applied.

What this most importantly tells us is that in fact you need to increase atmosphere samples! I would suggest still using highly adaptive AA (1/64, or at least 1/16), and using cloud quality of 0.5-1 (somewhere in that range), but use atmo samples of perhaps 12 or 16. Perhaps it justifies another set of tests just for that. In other words you are seeing noise in the tree test that is only coming from the atmosphere undersampling (cloud quality should not be having an effect here). Therefore, use render settings that are optimal for the clouds (as far as I can see this was AA12 with 1/64 sampling), and then increase atmosphere samples until noise level is acceptable. My bet would be that you'll end up with similar or lower render time for equivalent noise levels. But I could be wrong. I would love to see it tested. :D

The important take-away is that noise in the "atmosphere" of Terragen renders comes from two separate sources that each have their own individual quality/noise/sampling controls: clouds, and atmosphere. If you get good quality in one area (e.g. clouds), but not another, the ideal solution is not necessarily to change the overall settings (e.g. antialiasing level or adaptivity), but rather to try to change the settings just for that one element of the scene (the atmosphere in this case). In some cases it can be difficult to tell where noise is coming from just by looking at a render, for example where a dark area of atmosphere has a cloud behind it - noise could be coming either from the atmosphere between camera and cloud, or from the cloud shading itself. In these cases only testing will determine.

- Oshyan

penboack

#8
The values for settings in parentheses are the prior settings (to remind me what I was using previously), so for Render Test 5, the prior value was 12, not 6.
The render times confirm that, with AA6 the render time is 00:03:27 instead of 00:08:22 for AA12.

I checked through my notes before posting, so I am confident that they are accurate.
The line of text above the image describes which parameter has been changed.
The notes below the image give the values for the parameters that I am interested in.

The atmosphere has a quite high haze value, so yes you are right, I need to do some more tests with higher atmosphere samples and then see if the Adaptive AA can be used without needing to lower the pixel noise threshold to get a clean render of the forest, as lowering the pixel noise threshold clearly causes the render time to increase dramatically for the clouds.

The following tests were made on the Forest region to find the optimal value for the Atmosphere > Quality > Samples.
The earlier tests showed that reducing the Atmosphere > Quality from 32 to 16 to 8 did not have much impact on the render time for the clouds.


Comparison Render: Render Test 4.
Reproduced from my previous post to complete the set.
Render Test 4.
Forest Render Region from 4000 x 2000 Image
Forest Benchmark Render AA12 default sampling.
[attachimg=1]
Atmosphere > Quality > Number of Samples 8 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quality > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:08:22.


Render Test 14, Adaptive Sampling, Forest Render Region from 4000 x 2000 Image.
Atmosphere > Quality > Number of Samples 16 (Prior 8, Default 16)
First Sampling Level 1/16 (Prior 1/4, Default 1/4) first samples
[attachimg=2]
Atmosphere > Quality > Number of Samples 16 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:06:13
The render shows more noise in the forest than Render Test 4, but less noise than Render Test 10 (see previous post).


Render Test 15, Adaptive Sampling, Forest Render Region from 4000 x 2000 Image.
Atmosphere > Quality > Number of Samples 32 (Prior 16, Default 16)
First Sampling Level 1/16 (Prior 1/16, Default 1/4) first samples
[attachimg=3]
Atmosphere > Quality > Number of Samples 32 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:06:38
The render shows less noise than Render Test 4.


Render Test 16, Adaptive Sampling, Forest Render Region from 4000 x 2000 Image.
Atmosphere > Quality > Number of Samples 64 (Prior 32, Default 16)
First Sampling Level 1/16 (Prior 1/64, Default 1/4) first samples
[attachimg=4]
Atmosphere > Quality > Number of Samples 64 (Prior 32, Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:07:06
The best render yet. Increasing the Atmosphere > Quality > Samples from 8 to 64 has dramatically improved the noise level in the forest for a comparatively small increase in the render time.


Render Test 17, Adaptive Sampling, Forest Render Region from 4000 x 2000 Image.
Atmosphere > Quality > Number of Samples 64 (Prior 64, Default 16)
First Sampling Level 1/64 (Prior 1/16, Default 1/4) first samples
[attachimg=5]
Atmosphere > Quality > Number of Samples 64 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:05:49
The render time is now slightly shorter than that of the benchmark render, Render Test 4, there is also slightly less noise. The result is slightly inferior to Render Test 16.


Increasing the Atmosphere > Quality > Samples to 32 or 64 in combination with the use of Adaptive Sampling gives an acceptable level of noise in the forest region with a lower render time.

penboack

#9
Next up, cloud region render tests.

Render Test 18, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/16 (Default 1/4) first samples.
Atmosphere > Quality > Number of Samples 64 (Prior 8, Default 16).
[attachimg=1]
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:29:24


Render Test 19, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/64 (Prior 1/16, Default 1/4) first samples.
Atmosphere > Quality > Number of Samples 64 (Prior 64, Default 16).
[attachimg=2]
Atmosphere > Quality > Number of Samples 64 (Default 16).
EasyCloud > Quality > Quality 1 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/64 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:26:27.
Little difference in quality from Render Test 18. The render time is around 10% shorter.


Render Test 20, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/16 (Prior 1/64, Default 1/4) first samples.
Atmosphere > Quality > Number of Samples 64 (Prior 64, Default 16).
EasyCloud > Quality > Quality 0.5 (Prior 1.0, Default 0.75)
[attachimg=3]
Atmosphere > Quality > Number of Samples 64 (Default 16).
EasyCloud > Quality > Quality 0.5 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:30:25
Lowering the Cloud > Quality from 1 (Render Test 18) to 0.5 (this Render Test) increased the render time slightly, strange!


Render Test 21, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/16 (Prior 1/64, Default 1/4) first samples.
Atmosphere > Quality > Number of Samples 64 (Prior 64, Default 16).
EasyCloud > Quality > Quality 0.25 (Prior 0.5, Default 0.75)
[attachimg=4]
Atmosphere > Quality > Number of Samples 64 (Default 16).
EasyCloud > Quality > Quality 0.25 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/16 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:27:23
Lowering the Cloud > Quality from 0.5 (Render Test 20) to 0.25 (this Render Test) decreased the render time slightly.


Render Test 22, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/4 (Prior 1/16, Default 1/4) first samples.
Atmosphere > Quality > Number of Samples 64 (Prior 64, Default 16).
EasyCloud > Quality > Quality 0.25 (Prior 0.25, Default 0.75)
[attachimg=5]
Atmosphere > Quality > Number of Samples 64 (Default 16).
EasyCloud > Quality > Quality 0.25 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:31:47
With the Adaptive Sampling put back to the Default values the Render Time increases from 00:27:23 (Render Test 21) to 00:31:47 (this Render Test).


Render Test 23, Adaptive Sampling.
Cloud Render Region AA12, First Sampling Level 1/16 (Prior 1/4, Default 1/4) first samples.
Atmosphere > Quality > Number of Samples 32 (Prior 64, Default 16).
EasyCloud > Quality > Quality 0.25 (Prior 0.25, Default 0.75)
[attachimg=6]
Atmosphere > Quality > Number of Samples 32 (Default 16).
EasyCloud > Quality > Quality 0.25 (Default 0.75)
Render > Quaity > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)
Render Time 00:22:01
Increasing the Atmosphere > Quality > Samples from 32 to 64 increases the render time from 00:22:01 (this Render Test) to 00:27:23 (Render Test 21).


Conclusion:
Mixed results, the Adaptive Sampling in combination with lowering the Cloud Quality setting actually resulted in longer render times in some cases.

penboack

#10
Finally a Render Test of both regions with the following settings.
Atmosphere > Quality > Number of Samples 32 (Default 16).
EasyCloud > Quality > Quality 0.25 (Default 0.75)
Render > Quality > Micropoly Detail 0.6
Render > Quality > Anti-aliasing 12
First Sampling Level 1/4 (Default 1/4) first samples
Pixel Noise Threshold 0.025 (Default 0.025)

[attachimg=1]
Render Time Clouds Region: 00:25:16

[attachimg=2]
Render Time Forest Region: 00:06:49

The Cloud Region render time is in the middle of the range of render times for that region with no major compromises in the noise level.
These settings seem to be a good compromise. The Forest Region render is the best of all of the tests but with a render time that is slightly lower than the longest of the previous tests where the render times varied from 00:05:49 (Render Test 17) to 00:07:06 (Render Test 16).

The low Cloud Quality setting compensates for the high Anti-aliasing setting. The high Atmosphere > Quality > Samples setting greatly reduces the noise in the atmosphere that was affecting the forest region. The use of Adaptive Sampling did not seem to be effective because the benefits in the cloud region were offset by the additional noise in the forest region.

Oshyan

Very interesting tests indeed! Thanks for doing all this and for posting it. It seems like you've found a good balance for your particular scene. We hope to make all of this more automated and self-optimizing in the future, to save you (and others) this amount of testing. But for now you have a better understanding and a good starting point for future scenes, I reckon. Just keep in mind that the higher atmo samples will not be necessary in many other scenes; even with high haze, as long as there is not significant detail needing to be rendered in areas of shadow with lots of atmosphere between it and the camera, then you can get away with lower samples generally.

- Oshyan

penboack

Thank you for your advice, and thank you to Matt and paq for theirs, which was invaluable in setting up tests and getting a much better understanding of how the various settings work and interact.

One of the things that I found was that by keeping notes of the key parameters that I am testing the effect of in OneNote and running the tests as a kind of background activity on another PC it is much easier to carry out a large number of tests without needing to worry about the time they take to render or getting confused as to what was changed on the previous test.

A couple of weeks ago when I first got the Terragen 4 upgrade I did comparison renders of the scene in Terragen 3.4 and Terragen 4. The renders take half the time in Terragen 4 which is a huge improvement, like getting a computer that is twice as fast.

I just started a 2400x1200 render. I will post the results once they are rendered out.

Charles