Yes please report this, with a sample scene if possible 
A general info: Please report bugs to the bug tracker (Use Help → Report a Bug from within Blender). We cannot keep track of issues reported here.
1 Like
OK, I will report this with a sample scene. And here is another thing, transparent bsdf seems have a fixed refract ior like 1.45 or 1.60 which is much higher than I wanted. Is this possible to reduce this value by using graph/node tree? If not possible, I may change the source code, but I only find blender\kernel\shaders\node_transparent_bsdf.osl.
#include “stdcycles.h”
shader node_transparent_bsdf(color Color = 0.8, normal Normal = N, output closure color BSDF = 0)
{
BSDF = Color * transparent();
}
No idea where transparent() function comes, it is not in stdcycles.h.
The transparent BSDF does NOT refract light. You are probably observing some other effect.
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Thank you, my mistake.
Hi.
About defaults.
Since new AI denoisers handle fireflies correctly, is it worth it to continue clamping indirect light by default? I also think I remember reading that default Indirect Light clamping=10 was causing some problems with Nishita Sky Texture. (Edit: Default Clamp)
About Light Paths, I have noticed some times that for glass/transmission materials to look better it needs a bit more Glossy and Transmission bounces than the current default values.
4 Likes
I would personally be in favor of the indirect light clamp being increased. However, I believe setting the value to 0 (no clamping) is still a bad idea. From limited testing a value like 50 seems to be better. As it still reduces fireflies but doesn’t decrease the brightness as much as 10.
The reason I’m suggesting leaving clamping on is to continue to reduce fireflies is for people who do not wish to use denoising, or for people who wish to mix the noisy render result with the denoised result in compositing for “artistic effect”. And with adaptive sampling being the default, you can get some issues with fireflies that could potentially lead to denoising artifacts if no clamping was used.
6 Likes
Agree that the default light bounce can be higher, there can be some really obvious difference:
Probably also volume:
I have heard several times people complaining to me how Cycles volume scatter is dirty and heavy, then I asked them whether they set the light bounce higher, they would tell me they never touched it, didn’t even know it exists. So I think it makes sense to have the default be higher.
10 Likes
While I agree that 4 glossy bounces is not enough for rendering glass, 10 bounces is usually more then enough even for ill cases. It would be cool to make trapped rays escape glass after the last bounce by default, not just them being killed causing black areas around glass lips. So far I have to repeat the same shader setup over and over. Dispersion also would be welcome, but that requires either random per ray or spectral rendering =)
3 Likes
Is the dispersion parameter for transparent shaders planned for any future of Cycles, please?
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Not Transparent shader I think. But generally speaking I imagine that will be the task of the future for the Spectral Cycles branch after it completes the initial merge (hopefully in 3.1 or 3.2) :
This is probably not related to the topic here so if we are to discuss more about dispersion we should better move on to the the spectral thread.
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Hey, I have CyclesX crashing on so many scenes currently random.
How can I see the crash log? To report the bug
Christensen-Burley SSS is back for now:
https://developer.blender.org/rB73a05ff9e83a31be34d32a92cd5fb4d17994e342
I’m looking into this, we may add it back as a pass independent of denoising.
If you’re on Windows, the Blender install folder contains a blender_debug_gpu.cmd that you can run to generate debug logs. Generally, more important than crash logs is a .blend file to reproduce the problem. And then if we still can’t reproduce, a crash log can help.
17 Likes
Great!! Today I was using 2.93 at work and I just came in a situation where Random Walk just didn’t work but Christensen-Burley did very easily, and I wished we could have it back in 3.0! Thanks Brecht!
2 Likes
Thanks for taking time to reply Brecht, It’s awesome that you are looking into it! Fingers crossed to see it back in, independent from denoising seems even more fitting to such a useful utility pass. Thank you for all your incredible work!
No clamping can produce more noise in general, not just fireflies. But default value could certainly be increased to work better with the sky texture. How much clamping will darken the image depends on exposure and lights, but value between 30 and 50 should give better results out of the box.
Christensen-Burley SSS is back for now:
Thank you Brecht !
1 Like
Hey have the bug of everytime i render Blender crashes with AS at a random position → when not when a new Tile starts.
https://developer.blender.org/T92158
Have you seen this?
Nice paper the results are pretty impressive