Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: cecofuli on 2013-05-19, 18:07:51

Title: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 18:07:51
Hi,

as you can see, in the ceiling and windows I don't have noise.
but look at on the glass table (glass wit absorption).
You can see clear a lot of noise. Why?
DOF with Corona. Corona settings are default.

(http://www.francescolegrenzi.com/Temp/142_Noise.jpg)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-19, 18:58:58
You can try render this view in the alpha 4 version?
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 19:02:23
I use alpha4 =) Cause the good old "blur bug" in the daily version. And I don't know if it is fixed.
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-19, 19:31:10
I talked about the noise in reflection still in alpha version 3, keymaster said that fixed, it seems that is not fixed (
http://forum.corona-renderer.com/index.php/topic,377.0.html (http://forum.corona-renderer.com/index.php/topic,377.0.html)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 19:37:01
I think the same.
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-19, 19:41:12
You publish this work as done? Beautifully turns out!
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 20:34:49
Yes, why not =) This is a WIP

(http://www.francescolegrenzi.com/Temp/143_Caffetteria_0001.jpg)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-19, 20:38:45
Great! I Like it!
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 20:48:10
Thanks :)
Title: Re: Noise in the reflection table: bug?
Post by: Chakib on 2013-05-19, 23:15:00
what a fantastic render, cheers !
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 23:22:35
Chakib, it's just a simple coffee, but thanks. The shaders are in WIP, as many other stuff.
Another view.
Again, look the noise on the table, after 3 hours... :(

(http://www.francescolegrenzi.com/Temp/144_Caffetteria_0003.jpg)
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-19, 23:22:53
This is not a bug, just fewer samples are taken when the rays bounce from the table. Corona currently uses NO adaptivity. Just imagine the speed after I add it :D
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-19, 23:24:40
This is not a bug, just fewer samples are taken when the rays bounce from the table. Corona currently uses NO adaptivity. Just imagine the speed after I add it :D

So, do I just need time to remove the noise? When you'll add the adaptivity ^____^' , like in VRay?
and, what about the shadows through the solid glass?
As you can see in my floor, now I use a solid glass with "cast shadows" option disable in the shader.
Title: Re: Noise in the reflection table: bug?
Post by: racoonart on 2013-05-20, 00:01:22
This is not a bug, just fewer samples are taken when the rays bounce from the table. Corona currently uses NO adaptivity. Just imagine the speed after I add it :D

May the force be with you! (and with us afterwards!) If you'll make something as powerful as vrays dmc... man, i don't even find something i can say after that :) DMC + Corona fancyness ... wonderful
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-20, 00:08:44
This is not a bug, just fewer samples are taken when the rays bounce from the table. Corona currently uses NO adaptivity. Just imagine the speed after I add it :D

So, do I just need time to remove the noise? When you'll add the adaptivity ^____^' , like in VRay?
and, what about the shadows through the solid glass?
As you can see in my floor, now I use a solid glass with "cast shadows" option disable in the shader.
yes, I'll get to it, it's just that I'll need to again dig deep into the core to make that happen. So give me a week or two
Title: Re: Noise in the reflection table: bug?
Post by: Ludvik Koutny on 2013-05-20, 09:54:44
If your light sources are large (like windows) then caustics will not converge that slow. Try to set Max sample intensity to about 20, enable shadows in your glass material, and render close up of the chair shadow. I think the shadow will not be opaque, but will converge fast ;) The extreme clamping scenario usually happens only in cases with very small and bright light sources in a very dark environments ;)

Max. sample intensity (MSI from now on) does not make shadows opaque, or disable caustics. It just throws away samples that are significantly different than the average of samples taken from the given point. So if you have very large light, like window, where it will be very easy to calculate caustics even using regular path tracing, then not many samples will have significantly different value than the rest, so not much data will by thrown away and you should get transparent shadows with soft caustics. ;)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-21, 11:22:34
Again, noise in DOF, like in my old child bedroom. Also, fireflies on transparent chairs.
About DOF, I think I cannot do nothing. 8 hours and 450 passes are too much. I think Keymaster must to do something =(
For fireflies, if I disable the light, everything is ok. But, in the light option, I don't have "disable in reflection/refraction"
Corona parameters as default ( PTS= 32 , MSI 20 )
Some suggestion?  I cannot send to my client rendering with this noise...

(http://www.francescolegrenzi.com/Temp/145_Noise_Fireflies.jpg)
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-21, 11:35:10
PT samples are 16 by default, right? And you should lower it if you are using DOF, to about 4
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-21, 11:37:14
No, 32, as in the interactive Guide. But I try with 4 in a crop. What about the white fireflies?
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-21, 11:59:49
you can try for example disabling the visibility of the light, or lowering max depth
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-21, 12:02:40
Better with PT= 4. Max depth = Ray Depth? Now is 25, by default. Usually in VRay is 5. Or am I wrong?
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-21, 12:38:45
The only way to "solve" (It's better say reduce)  the fireflies is changing "Internal res" from 2 to 4.
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-21, 12:47:21
Or use this free tools. But, obviously, it adds "blur" to the  rendering.

Defly - firefly and hot pixel noise removal tool (http://www.visnevskis.com/index.php?id=95)
Title: Re: Noise in the reflection table: bug?
Post by: maru on 2013-05-21, 14:23:24
Or render in huge resolution with "do antialiasing" disabled and then downsample in photoshop.
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-21, 14:26:46
Quote
Also, fireflies on transparent chairs.
This is Alpha-4 bug! In the last builds is fixed!
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-21, 14:30:11
It does not necessarily needs to be. If there is a complicated glass structure, then since on every surface you have both reflection and refraction, the number of possible paths grows exponentially with ray depth, and you get something with fractal behaviour. If you the have thousands of possible ray directions for single pixel, the probability that some of them hit the sun randomly grows, and so you get frequent bright spots. This is physically correct behaviour, and Corona should converge to the physically correct result in the long run, although it is certainly undesirable for this kind of renders.
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-21, 15:04:55
Here are the fireflies on transparent objects (post from mantis).
Or is it not?
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-21, 15:18:13
which ID is this, this looks like good old NaNs
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-21, 15:42:40
0000231
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-22, 11:47:16
With the new version, noise and fireflies. But after 9 hours, the noise is too much.
Any suggestion?

(http://www.francescolegrenzi.com/Temp/146_Noise.jpg)
Title: Re: Noise in the reflection table: bug?
Post by: maru on 2013-05-22, 12:20:17
More PTS, less MSI.

You can try selecting a small square on the noisy area and letting it render for the same amount of passes that you got after 9 hours. Try changing lights samples multiplier.

You could also show HD cache settings.
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-22, 12:30:59
You can post part of scene (with noise and fireflies)? I would tried to help.
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-22, 13:44:50
PTS = 4 for DOF, as Ondra suggested me.  MSI = 50 for better highlight.
HD as default. Never change.  I'll rty with crop and see what happen.

Yes, I have the scene both in VRay and Corona.
I want to clean-up and post here both files.
With VRay and sub-pixel mapping OFF was impossible to render in decent time.
When buckets are  over transparent chairs, DMC sampler becomes CRAZY!!!
This is a "big problem" in VRay, as Vlado wrote me. 
Look my old VRay thread  LINK (http://www.chaosgroup.com/forums/vbulletin/showthread.php?71891-Sub-pixel-ON-OFF-phisical-INCORRECT-noise-and-rendertime&highlight=sub-pixel)

If you want to compare VRay and Corona (or MW, Arion, Octane) sub-pixel mapping must be OFF.

IOR for chairs is wrong. And I don't like the shader/color. But this idea is from my architect :(
S curve, CC , Sharp and denoise in PS


(http://www.francescolegrenzi.com/Temp/147_Caffetteria_0003.png)
Title: Re: Noise in the reflection table: bug?
Post by: maru on 2013-05-22, 14:34:29
HD as default. Never change.
Maybe you should try with different settings. You can always revert to original values with right click.
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-22, 14:36:22
good, but I don't know how HD parameters influence the noise XD
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-22, 15:00:55
With the  new daily build, something different in the chairs reflection.
I change a little bit the power of lights, but not the IOR...
I don't like the "back table reflections" inside  the chairs... =(
 
PS: no fireflies ;-)

(http://www.francescolegrenzi.com/Temp/148_output.gif)
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-22, 15:03:52
yes, it behaves differently, I'll look into it today or tomorrow
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-22, 15:05:53
Ok. Thanks! And... do you have some suggestion for the noise in the black area?
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-22, 16:02:08
no... either give it more time or wait for the adaptivity ;)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-25, 19:00:07
Here the scene just for testing purpose.

As you can see, after one hour, for this resolution, is enough and with double time we don't have significant improvement in the noise quality. (PT+HD)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/11_Corona_00000.png)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/12_Corona_00003.png)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/13_Corona_00006.png)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/14_Corona_00007.png)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/15_Corona_00012.png)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/16_Corona_00015.png)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/17_Corona_00019.png)

Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-25, 19:04:06
But I don't understand the differences between PT-HD (lighter) and PT+PT (darker)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/18_Cecofuli.gif)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-25, 19:13:22
Here a render at 3000px after 9 hours!!!
Good quality after 3 hours, but the noise, created by lights on the reflective surface, is still here =(
Ondra needs to works on this "bug-problem".
 
PTS = 6
MSI =  20
Lights samples = 4


(http://www.francescolegrenzi.com/Works/38_cecofuli_test/19_Corona_3000px.png)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-25, 19:23:35
try set refl.gloss to 0.99 or (0.999) for clear refl, in the alpha 3 it's help me.
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-25, 19:34:20
thanks for the suggestion. I'll try ;-)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-26, 18:32:03
Polymax, I didn't solved the problem with glossy at 0.99.

sole sligtlhi better result with Lights subdivs, but... I thing we have to wait Ondra and new Corona render.
Too much noise in the reflection lights, after... 18 hours!!!  (Final output 3K)

(http://www.francescolegrenzi.com/Works/38_cecofuli_test/24_Corona_3000px_Light_subdivs.png)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-26, 19:45:09
In light sources (hidden illumination) visibility is on?
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-26, 19:51:52
As default. I didn't touch nothing.  )
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-26, 20:52:19
I tried to repeat, well, maybe other conditions ...
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-27, 00:38:58
Soon I'll send you the full Corona scene =)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-28, 18:48:31
I did a quick test.
Slightly changed the render settings.
Crop mode rendering (therefore, the noise is more than a "view" mode), 250 pass
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-28, 18:51:32
Interesting. What's about the noise on the chrome spotlight, on the top-right side of the brown ceiling? 
Obviously, what did you change? =)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-28, 19:04:46
Interesting. What's about the noise on the chrome spotlight, on the top-right side of the brown ceiling? 
Obviously, what did you change? =)
ok. i try crop render of chrome spotlight!
I slightly changed the render settings.
Tonight I will render in high resolution, tomorrow will show the result :)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-28, 19:27:36
Can I ask you what parameters did you change? MSI? Lights samples?
Is the DOF off? Why?
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-28, 19:44:50
I reset renderer to default and changed:
1. Exposure compens = 4
2. Highlight comp = 5
and that's all :)
Well I need more time to achieve the best result, so tomorrow I will see what should be changed more (after hires render) :)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-28, 19:57:45
Only these? Mmm... I have to try me too =)
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-29, 07:33:33
I'll have to test with your scene, but now the result is:
What do you think?
PS. I use the method of solving the problem "step by step", so while rendering without the DOF! ;)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-29, 09:30:45
Good, but, as you can see on the chrome lamp, after 4 hours, still very noisy. Can you share your renderer setting by a screenshot?
Title: Re: Noise in the reflection table: bug?
Post by: Polymax on 2013-05-29, 10:01:55
I tried to explain in the picture:
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-29, 10:05:19
So, you suggest me to replace the real CoronaLights with Mesh + CoronaMtl emitters? Ok, I'll try...
Title: Re: Noise in the reflection table: bug?
Post by: Stan_But on 2013-05-29, 15:35:48
Quote
So, you suggest me to replace the real CoronaLights with Mesh + CoronaMtl emitters? Ok, I'll try...

light mesh emitters are very noisy now. As and very many lights too.
Corona lights + coronaconstant mat will help you get out from noise
Title: Re: Noise in the reflection table: bug?
Post by: maru on 2013-05-29, 16:14:10
Try this:

PTS: 24
LSM: 1


HD CACHE:
PT SAMPLES: 1024
pos sensitivity: 10

refl glossiness threshold: 1

Region-select a small square with lots of noise and render.
Title: Re: Noise in the reflection table: bug?
Post by: Ondra on 2013-05-29, 16:30:57
it is not that simple, you will get different results (noise-wise) when rendering small region/entire picture with HD cache - small region will not properly fill the cache.
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-29, 16:59:29
Try this:

PTS: 24
LSM: 1


HD CACHE:
PT SAMPLES: 1024
pos sensitivity: 10

refl glossiness threshold: 1

Region-select a small square with lots of noise and render.

Hi maru,
ok, I'll try a 1080p resolution tonight ;-)
Title: Re: Noise in the reflection table: bug?
Post by: maru on 2013-05-29, 21:55:45
it is not that simple, you will get different results (noise-wise) when rendering small region/entire picture with HD cache - small region will not properly fill the cache.
This explains a lot. :)
Title: Re: Noise in the reflection table: bug?
Post by: cecofuli on 2013-05-30, 12:26:29
Nothing to do...
With LSM: 1 I have a lot, a lot of noise coming from the arealight (areashadows)
Much better with LSM = 20 or 30.
The noise in the glossy surface, there lights are reflected still here.
After many test, I think the "solution " in to wait Ondra ;-)