Radiosity and fuzzy shadows

prometheus

REBORN
I was thinking more that if you have a highly specular (reflective) object casting a shadow on a highly specular (reflective) ground plane, there will be more light bounces between them that require evaluation. If your samples aren't high enough, you aren't evaluating them, thus noise.

Rather than raising your light samples, it seems worth it to me to check to see if your material is 50% or more specularity and then reducing it if the material doesn't require that much specularity.

Then just try another render. You may get a smoother shadow at lower samples with the benefit of less rendering overhead.

Quick testing..

I think I have to stand a bit corrected, but I don´t think that has to do with highly specular surface or pure roughness, it´s just that the ray samples need to be evaluated per surface when ray hit´s.

The surface noise in the parts of any surface that is in the shadows, it will not matter much if you raise the light samples, the light samples seem to only bother about the softness in the shadow if it has any softness angle set to it to produce softer shadow at the ends of the shadow, or if using domelight or a very high angle similar to producing completely soft shadows, and that was what was the issue. (increase light samples)

Another issue is the actual (shadow) noise on any surface being in the shadow, that can´t be cleared up by increasing light samples, but have to be adressed with cam samples, going from 4-15 perhaps.

But you also talk about roughness and specularity which I believe introduces the other type of noise such as fireflies, which is a bit different.
 

prometheus

REBORN
Here´s three samples,
first image with lowest light sample, yielding very noisy end shadow softness, low cam sample at 3 isn´t clearing up noise much at that level on the surface.

Second image increased cam sample to 10, and it´s getting much better for surface noise and slightly better on the end shadow also, but there is still noise in the end shadow that will not be cleared up with cam samples.

Third image increased Light samples to 10, and the noise on the end shadow is cleared up a bit more, it may be hard to see it on these images stacked up like this, but if you overlay them and check you will see the difference.
So samples goe´s from light to cam samples
1,3
1,10
10,10
And the light sample contributes pretty much only to the angled shadow dispersion softness, while cam sample will help out on both, but I don´t think roughess settings on pbr surfaces will contribute to affect this type of noise.

1.jpg


2.jpg

3.jpg
 

prometheus

REBORN
and here´s two more, this time around keeping low values on light samples and cam samples, but increasing GI samples from 1 to 10 , yielding better cleared up shadow noise on the surface apart from the end angle of the shadow, which needs both increased ligh and cam sample.

The first image without increased reflection samples (only one) thus the issue you are probably talking about, which is more white speckle noise and some smaller fireflies.
The second image with still same light and cam samples and same GI sample at 10, but increased reflection sample to 20, which is clearing up white speckle noise and smaller fireflies, but still could use increased light samples to clear shadow softness noise, and slight cam sample to clear up the shadow noise on surface.

4.jpg



5.jpg
 
First: can it be that Geoff Vane still uses LW 11? In another thread he wrote something like that, if I'm not mistaken.

However in LW 2018 - LW 2020:
Instead of countless trial and error, you should look at the buffers used in the scene.

Noise in Alpha Buffer: AA Samples
Noise in Diffuse Indirect Buffer: GI Rays / AA Samples
Noise in Specular Direct Buffer: Light Samples
Noise in Diffuse Direct Buffer: Light Samples
Noise in Shadow Buffer: Light Samples
Noise in Specular Indirect Buffer: Reflection Samples
Noise in Refraction Buffer: Refraction Samples
Noise in SSS Buffer: Subsurface Samples

Of course, you only have to look at the buffers that actually used in the scene, depending on the materials and render or volumetrics settings (for what there are more buffers).

Increase the samples only where noise is visible. In the Diffuse Indirect Buffer, the noise can come from too few GI or AA samples. Here you have to test a little bit.

Note: if you increase the Camera samples, you should reduce the Shading samples accordingly, as they will be multiplied by each other. Also Light Samples will be multiplied by Shading Samples and added to the Camera/Shading Samples (Camera Samples * Shading Samples + Light Samples * Shading Samples).

So if the Reflection Buffer is noise free and the Camera Samples have to be increased then you should reduce the Reflection Samples to achieve the same product.

Generally speaking, it is advantageous to adjust the camera and light samples first and then the necessary shading samples.

In versions before LW 2020, you should definitely set "Affect Specular" to ON for Environment lights and the Surface Reflection Options to "Rayrace Only" (Since the Environment Light uses MIS samples). More about it in this thread.
In LW 2020, this works automatically.

So much for the general procedure.

Finally, use a noise filter. Best Denis Pontonnier implementation of Open Image Denoiser.
You can find it here: https://dpont.pagesperso-orange.fr/plugins/nodes/DP_Filter.html

ciao
Thomas
 
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prometheus

REBORN
First: can it be that Geoff Vane still uses LW 11? In another thread he wrote something like that, if I'm not mistaken.

However in LW 2018 - LW 2020:
Instead of countless trial and error, you should look at the buffers used in the scene.

Noise in Alpha Buffer: AA Samples
Noise in Diffuse Indirect Buffer: GI Rays / AA Samples
Noise in Specular Direct Buffer: Light Samples
Noise in Diffuse Direct Buffer: Light Samples
Noise in Shadow Buffer: Light Samples
Noise in Specular Indirect Buffer: Reflection Samples
Noise in Refraction Buffer: Refraction Samples
Noise in SSS Buffer: Subsurface Samples

Of course, you only have to look at the buffers that actually used in the scene, depending on the materials and render or volumetrics settings (for what there are more buffers).

Increase the samples only where noise is visible. In the Diffuse Indirect Buffer, the noise can come from too few GI or AA samples. Here you have to test a little bit.

Note: if you increase the Camera samples, you should reduce the Shading samples accordingly, as they will be multiplied by each other. Also Light Samples will be multiplied by Shading Samples and added to the Camera/Shading Samples (Camera Shading * Shading Samples + Light Samples * Shading Samples).

So if the Reflection Buffer is noise free and the Camera Samples have to be increased then you should reduce the Reflection Samples to achieve the same product.

Generally speaking, it is advantageous to adjust the camera and light samples first and then the necessary shading samples.

In versions before LW 2020, you should definitely set "Affect Specular" to ON for Environment lights and the Surface Reflection Options to "Rayrace Only" (Since the Environment Light uses MIS samples). More about it in this thread.
In LW 2020, this works automatically.

So much for the general procedure.

Finally, use a noise filter. Best Denis Pontonnier implementation of Open Image Denoiser.
You can find it here: https://dpont.pagesperso-orange.fr/plugins/nodes/DP_Filter.html

ciao
Thomas

The only thing to get answered from him, is what LW version he is using, otherwise, check the first post and the image he posted..to me it is very clear there is only noise in the end of the shadow and the light is a dome light, and that is to be fixed with light sampling and to some degree cam samples all the other things and stuff I also posted, is a bit irrelevant in this case.

For other cases when understanding what part is causing the issues, I can only agree with what you have said.
 
The only thing to get answered from him, is what LW version he is using, otherwise, check the first post and the image he posted..to me it is very clear there is only noise in the end of the shadow and the light is a dome light, and that is to be fixed with light sampling and to some degree cam samples all the other things and stuff I also posted, is a bit irrelevant in this case.

For other cases when understanding what part is causing the issues, I can only agree with what you have said.

Of course, in his picture it looks like the shadow edges are causing the problem. If so only the light samples are responsible for it and not the camera samples (these also reduce noise but also increase render times unnecessarily)!
To determine this you should look at the individual buffers. This is the only way to clearly identify what is causing the noise (and if other sample settings are too high).

ciao
Thomas
 

prometheus

REBORN
Of course, in his picture it looks like the shadow edges are causing the problem. If so only the light samples are responsible for it and not the camera samples (these also reduce noise but also increase render times unnecessarily)!
To determine this you should look at the individual buffers. This is the only way to clearly identify what is causing the noise (and if other sample settings are too high).

ciao
Thomas
It's not the Only way to clearly identify what is causing this issue, not in this case, by default we know the light in matter has a too low default sample setting, thus it's a 100% chance of yielding noise in the end of the shadows.

That said..if you do not know this..I agree with you ;).
 
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Geoff Vane

Worst 3D artist ever
The light samples are indeed hidden in the render tab.
(For me the parameters seem scattered all over the place. And their names often don't speak to me)
I found the light samples and setting these to 4 immediately removed all noise.
 

prometheus

REBORN
We could have solved this with only two post in this thread, but that requires that people describe what Lightwave version they are using from the very beginning, and those trying to answer not rushing away before getting that in place in the first place, that includes me as well :D.

Not until post 14 did someone ask what Lightwave version you used, and that was I think actually me :D

So no wonder you got suggestions that weren´t matching your Lightwave version.
Light samples isn´t in the render tab (surface and shading samples is) Light samples is in the light properties in Lightwave 2018 and up, but for Lightwave 2015 and maybe below, Light samples is in the render tab.
 

prometheus

REBORN
Gee. Kind what I said in my first reply ... ;)
I don´t see you mentioning that in your first reply that has anything about light samples being in the render tab and in reference to 2015 lw version, your first reply was mostly just linking to rebel hill´s video...which was showcasing sampling in 2018 and up, not lw 2015.
:D
 
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