Animation rendering artifacts - noob questions

Started by amandas, February 05, 2021, 05:12:50 AM

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amandas

Hi there,

I am making my first attempt at a planetary sequence. I made a first preview render and noticed rendering artifacts - would appreciate a helping hand.

Prev: http://arturmandas.com/tempVids/planet.mp4

TGN 4.5.56
Path Tracer, max. paths 16
Micropoly Detail 0.4
Anti-aliasing 1

Rest at default values.


I see 2 issues there: flickering and noise. I am guessing reverting to default renderer and upping AA to 3 should be enough. Should it?

Also, I have huge problems getting the right values for large scale clouds - it would be good if there were presets not only for specific look, but distance as well. Is there a guideline for that, somewhere?

Thanks in advance.
Artist / Developer
open for freelance / full project cycle
http://arturmandas.com

WAS

#1
The flicker is likely because you haven't generated GI for the animation, so it's generating a new GI for each frame on the fly and introducing variations. I remember increasing the GI blur radius helped, and it's default far to low for animation, where people use like 200+ for it's value.

Additionally, I would suggest using the soft AA Filter to prevent pixel optimization variation between frames (which creates noise in animation). Sharpen in post. These artifacts are very noticeable unless you're at a really high resolution. Also, you'll need higher AA unless you heavily customize the pixel noise threshold for something like this with lots of contrasting colours/light.  Soft AA will only help so much here but still needs higher AA.

PS I suck at animation, so try my advice with a grain of salt, and maybe wait for the masters.

Nala1977

honestly i wouldnt use path tracer for this, also AA 1 is extremely low and can produce jagged edges that when are animated makes the flicker
try mpoly detail 0.5, AA 4 and switch to normal render, not Path tracer

WAS

#3
Found a issue with GI. At a certain distance, it doesn't cache any GI from the planet, so it renders a blank GI, and thus a blank render. It's not until around frame 50 that the camera is close enough in my tests.

This probably explains my suns issue about cloud distance sampling, or I was outside the background sphere (which is at default size in this test)


Update: So I did a test animation and did some pretty "high" settings but still had some white pixel flicker and faint noise. Also some weird GI caching circles that you can see on the surface at the beginning. So I think the GI blur radius needs to be much higher then what I used, and the pixel noise theshold needs to be even lower, and/or AA increased.

Settings: 
MPD: 0.2
AA 3 (PNT 0.05)
GI cache quality 8
GI sample quality 8
GI blur radius 8

Also did "Animation Check..." under sequence tab

I rendered a sequence of the the GI cache files, and used the blending between 5 files (not sure which ones it uses as I used as I added same sequence %04d to the loading. Not sure if that's correct to do but there isn't actually much docu on doing a cache sequence.


Hannes

Hi Amandas. Nice to see people making animations. :)
In my opinion you don't need GI for this kind of animation at all. As you can see in your clip, the planet isn't completely unlit on the dark side, which looks a bit unnatural. If you want to turn it off, go to Render/GI settings and set GI cache detail and GI sample quality to 0.
The path tracer is also absolutely not needed here. And as the others said, AA 3 is way too low. Depending on which quality you want, I'd start with a minimum of 6.

WAS

#5
Atmosphere shadow may be off which is why backside is glowing. Too bright of a light source node can do it too. In the Binary scene, the suns couldn't go brighter without the backside of the planet illuminating, and imo aren't bright enough to make the 0.25 colour clouds white (without orbit lighitng model)

If you plan on adding a star background you'll probably need AA 7 PNT 0.01 on soft filter in order to prevent flickering there.

amandas

Hi guys,

thank you very much for support! I've received much info that will certainly help me. Lots of helpful tips. The flickering was what worried me most. I will disable GI, not needed, also I need to minimize render time here.

Again, thanks!
Artist / Developer
open for freelance / full project cycle
http://arturmandas.com

Kadri

#7

I had sometimes problem with flickering too.
Try to lower unneeded detail of the fractals (don't use small scales so much you can).
It helps with render times too.

For some scenes i rendered a much bigger image and used it as a front projection for the landscape, planet etc.
With these kind of textures you will get much less flicker and faster render times in general.

I was rendering a scene with mountains from 20 km or so above the planet right now.
Render times were more then 1 hour per frame. I exported the landscape as an object and used that instead the original fractal one.
Now render time is 10-15 minutes per frame. One problem is you have to use quite a big object for this or you loose quite a detail.
I could have used an exported hightfield too probably for this. The detail could have been better too then an object.
So it depends on your scene and what you want to do.

But in general if you want to use scenes like you posted they are mostly very fast to render if you don't go too close for very fine detail.
And motion blur (direct or postwork) helps too.

amandas

Quote from: Kadri on February 07, 2021, 10:40:14 AMI had sometimes problem with flickering too.
Try to lower unneeded detail of the fractals (don't use small scales so much you can).
It helps with render times too.

For some scenes i rendered a much bigger image and used it as a front projection for the landscape, planet etc.
With these kind of textures you will get much less flicker and faster render times in general.

I was rendering a scene with mountains from 20 km or so above the planet right now.
Render times were more then 1 hour per frame. I exported the landscape as an object and used that instead the original fractal one.
Now render time is 10-15 minutes per frame. One problem is you have to use quite a big object for this or you loose quite a detail.
I could have used an exported hightfield too probably for this. The detail could have been better too then an object.
So it depends on your scene and what you want to do.

But in general if you want to use scenes like you posted they are mostly very fast to render if you don't go too close for very fine detail.
And motion blur (direct or postwork) helps too.
Thank you, will do much smoothing in post, using motion vectors.
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amandas

What helped me most is the GI and pixel reconstruction filter tips - I am guessing here that for large cam-to-planet distance deltas the probability of artifacts is significant; smooth filter helps to mask that.
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Tangled-Universe


amandas

Quote from: Tangled-Universe on February 08, 2021, 12:15:44 PMPlease show the result eventually :)

Thanks, sure, will do. I will probably use Intel Image Denoiser to speed things up a bit.
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WAS

Quote from: Kadri on February 07, 2021, 10:40:14 AMTry to lower unneeded detail of the fractals (don't use small scales so much you can).
It helps with render times too.

I wanted to touch on this real quick. While this is mostly true, for quality in the scene it's best to balance octaves or min scale with displacement detail.

For colour maps I usually have min scale at 10-100. But for displacement PFs, I have the displacement roughness at 1.5-2.5 which helps bring out orbital terrain detail. Because when colour, and displacement are both too smooth, your planet ends up looking flat and blurry.

Kadri

What i mean is something like this below.
First image is with 0.01 minimum scale, second 0.1 and third 1. There is difference, but very small.
If you do something like the 4. image (minimum scale 10) that is another thing of course.

amandas

Quote from: Kadri on February 09, 2021, 04:36:32 PMWhat i mean is something like this below.
First image is with 0.01 minimum scale, second 0.1 and third 1. There is difference, but very small.
If you do something like the 4. image (minimum scale 10) that is another thing of course.

This is a very nice comparison, thanks!
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