strange point ( pixel ) trough glass

[walterfog]

hello,

i was working in a scene, that is something like a wardrobe cabinet, with glass door... and inside this wardrobe there are spotlight to the ceiling, that i made with corona light, the type is " sector " and it is a sphere sector... the problem is that you could see in the picture... when light pass throughout the glass, very strange pixel were made by corona... and this is not normal noise, cause this pixel increase during the render time...
i was trying many and many solution... change light type... reflection... refraction..etc.... deleting also the glass of the wardrobe doors... the problem still remain, and not only in this scene, but in all the scene like this... what happen??

[houska]

Hi there! Thanks for the report. It looks like a standard firefly, but you're saying it does not behave like one... Could you post a simple scene where this is happening?

Thank you :-)

[walterfog]

Hi there! Thanks for the report. It looks like a standard firefly, but you're saying it does not behave like one... Could you post a simple scene where this is happening?

Thank you :-)

this is a simple scene where this happen through the glasses... this happen when in the light mix you increase the light " SPOT SOFFITTO "... if you turn off this light the strange pixel disappear....

[walterfog]

Hi there! Thanks for the report. It looks like a standard firefly, but you're saying it does not behave like one... Could you post a simple scene where this is happening?

Thank you :-)

this is a simple scene where this happen through the glasses... this happen when in the light mix you increase the light " SPOT SOFFITTO "... if you turn off this light the strange pixel disappear....

it is this bug fixed yet??? could anyone reply please??

[maru]

LightMix has some limitations, and greatly increasing and decreasing light intensities, and turning them off, is one of them. This is expected to introduce persistent noise, fireflies, etc, simply because sampling becomes inefficient then.
On the other hand, I tested the reported scene, and even with all lights disabled but the "SPOT SOFFITO", the fireflies did eventually go away after some extra passes when I used region rendering on them. Denoising could help too.

[houska]

Hi walterfog and sorry for the delay,

we tried your scene and found some 3rd-party plugins (Maxwell material and V-Ray bridge nodes in render settings). When we deleted these plugins from the scene, there were no problematic fireflies. This is probably because you're using the Maxwell material for the incriminated spotlights? We are terribly sorry, but we cannot support all third-party plugins that are out there. Could you try to reproduce this problem with Corona plugins only?

Thanks you!

[walterfog]

Hi walterfog and sorry for the delay,

we tried your scene and found some 3rd-party plugins (Maxwell material and V-Ray bridge nodes in render settings). When we deleted these plugins from the scene, there were no problematic fireflies. This is probably because you're using the Maxwell material for the incriminated spotlights? We are terribly sorry, but we cannot support all third-party plugins that are out there. Could you try to reproduce this problem with Corona plugins only?

Thanks you!

sorry but i really don't understand what your meaning... in this scene there is not maxwell or v-ray plugin.. at all...  and in the render setting there is only corona setting... this scene was made by a clean and new c4d scene, with only corona installed.... no other third-party plugins are there... there was only 1 maxwell materials that in used in some mesh... sorry... only a little mistake...  i've replace them with a white corona material but the problem still present... as you could see from the attached pictures, the problem is only when the light SPOT SOFFITO is turned ON... if the turn OFF the spot soffitto the fireflies disappear... no maxwell or v-ray matter in this ...

[houska]

Hi walterfog and sorry for the delay,

we tried your scene and found some 3rd-party plugins (Maxwell material and V-Ray bridge nodes in render settings). When we deleted these plugins from the scene, there were no problematic fireflies. This is probably because you're using the Maxwell material for the incriminated spotlights? We are terribly sorry, but we cannot support all third-party plugins that are out there. Could you try to reproduce this problem with Corona plugins only?

Thanks you!

sorry but i really don't understand what your meaning... in this scene there is not maxwell or v-ray plugin.. at all...  and in the render setting there is only corona setting... this scene was made by a clean and new c4d scene, with only corona installed.... no other third-party plugins are there... there was only 1 maxwell materials that in used in some mesh... sorry... only a little mistake...  i've replace them with a white corona material but the problem still present... as you could see from the attached pictures, the problem is only when the light SPOT SOFFITO is turned ON... if the turn OFF the spot soffitto the fireflies disappear... no maxwell or v-ray matter in this ...

Well, it could be that I made a mistake, but the matter of fact is that I was not able to reproduce your problem. I'll try again with the new scene. Thanks for providing it!

[walterfog]

Hi walterfog and sorry for the delay,

we tried your scene and found some 3rd-party plugins (Maxwell material and V-Ray bridge nodes in render settings). When we deleted these plugins from the scene, there were no problematic fireflies. This is probably because you're using the Maxwell material for the incriminated spotlights? We are terribly sorry, but we cannot support all third-party plugins that are out there. Could you try to reproduce this problem with Corona plugins only?

Thanks you!

sorry but i really don't understand what your meaning... in this scene there is not maxwell or v-ray plugin.. at all...  and in the render setting there is only corona setting... this scene was made by a clean and new c4d scene, with only corona installed.... no other third-party plugins are there... there was only 1 maxwell materials that in used in some mesh... sorry... only a little mistake...  i've replace them with a white corona material but the problem still present... as you could see from the attached pictures, the problem is only when the light SPOT SOFFITO is turned ON... if the turn OFF the spot soffitto the fireflies disappear... no maxwell or v-ray matter in this ...

Well, it could be that I made a mistake, but the matter of fact is that I was not able to reproduce your problem. I'll try again with the new scene. Thanks for providing it!

this is not a new scene... this in only 2 screen shot that show you what happen, when we turn off or on only the SPOT SOFFITTO light in light mix.... are you testing under WIN or OSX ? i use OSX 10.9.5
so in the previous scene i posted you only have to replace ( ALT + drag )  the material ( maxwell ) SPOT with a common white corona material... the problem still again...

[houska]

this is not a new scene... this in only 2 screen shot that show you what happen, when we turn off or on only the SPOT SOFFITTO light in light mix.... are you testing under WIN or OSX ? i use OSX 10.9.5
so in the previous scene i posted you only have to replace ( ALT + drag )  the material ( maxwell ) SPOT with a common white corona material... the problem still again...

Ok, so this is new information. It could be that it's not reproducible on Windows, but only on Mac. In general, it's good to state your hardware setup and OS beforehand, as it might clear up some confusion. We'll try it on Mac then. Thanks for this information!

[walterfog]

this is not a new scene... this in only 2 screen shot that show you what happen, when we turn off or on only the SPOT SOFFITTO light in light mix.... are you testing under WIN or OSX ? i use OSX 10.9.5
so in the previous scene i posted you only have to replace ( ALT + drag )  the material ( maxwell ) SPOT with a common white corona material... the problem still again...

Ok, so this is new information. It could be that it's not reproducible on Windows, but only on Mac. In general, it's good to state your hardware setup and OS beforehand, as it might clear up some confusion. We'll try it on Mac then. Thanks for this information!

the problem is that it persist in the WIN too.... i have a workstation with only c4d and corona... no maxwell or v-ray and the same fireflies happen too in windows... :-(

[houska]

the problem is that it persist in the WIN too.... i have a workstation with only c4d and corona... no maxwell or v-ray and the same fireflies happen too in windows... :-(

Are you aware of what Maru wrote, right? If you are using LightMix and the light was originally very dim, you cannot expect it to be able to scale up without additional noise. This is not a bug, but an inherent feature of the pathtracer. What makes your renderings normally converge faster will in this case cause more noise, because the renderer didn't know the light will be so intense in the end!

Of course, if you are not ramping the intensity up, it should not increase the noise, so this might be a bug. We just need to cross out the obvious causes (and of course, so far, none of us here in Render Legion was able to reproduce it).

[Nikola]

Hi,

I can confirm Cestmir conclusion. When I render the image with SPOT SOFFITTO set to 0 there are no fireflies but then when I set the value of SPOT SOFFITTO in LightMix to 60, fireflies appear, and the reason is the one described by Cestmir. Alternatively, you can increase the intensity of the SPOT SOFFITTO light and then you can lower its multiplier value in LightMix tab because when you are lowering the multiplier value (as opposed to increasing it), you cannot get the fireflies.

Nikola

[walterfog]

Hi,

I can confirm Cestmir conclusion. When I render the image with SPOT SOFFITTO set to 0 there are no fireflies but then when I set the value of SPOT SOFFITTO in LightMix to 60, fireflies appear, and the reason is the one described by Cestmir. Alternatively, you can increase the intensity of the SPOT SOFFITTO light and then you can lower its multiplier value in LightMix tab because when you are lowering the multiplier value (as opposed to increasing it), you cannot get the fireflies.

Nikola

hi nikola.... i try what you told me and at the first sight it seems to work fine... :-) :-) i will made other tests but the solution you give me seems to finally delete any fireflies.... :-) thanks a lot for your support guys... :-)

[maru]

By the way, and for other users, basic info on the LightMix and its limitations can be found here: https://coronarenderer.freshdesk.com/support/solutions/articles/12000017218