Hey,
That’s right. Did the render time change too dramatically between 0.001 and 0 though? This was the main concern when we left it at 0.001 by default.
Cheers!
I will make a test for u
@svetlin - the correct thing we need to do (for the v-ray lights as well, when I get to it) is outside the threshold to just sample the lights probabilistically…
Best regards,
Vlado
Well, currently Phoenix samples them probabilistically inside the threshold and does not sample them at all when the intensity is under the threshold. This is another aspect of the problem with managing the emissive lights inside Phoenix. Ultimately, a new V-Ray light would be the solution.
Sorry to hijack the thread, but I think I’m having the same problem.
I’m not getting banding, but a lot of noise / fireflies in reflections.
In that attached render, Phoenix Light Cut-off is 0.002. If I lower it to zero, I get only noise in reflections.
If I set it to like 0.01, Reflections are clean, but the light banding is visible.
Yup, this is exactly the weak point of the emissive lights as they are right now - reflections, especially glossy ones, would be very noisy, because Phoenix is trying to handle V-Ray’s job on its own.
Ok thanks, good to hear that you already know where the problem is.
Keep us updated when you find a solution.
Roger that - this is one of the areas that would need the most attention.
With my tank firing scene I emit and reflect light on the ground and it’s really noisy and full of fireflies. Is there any workaround you could suggest while you find a solution?
I tried using only GI (emit light off) and it’s the same. Maybe increasing subdiv of the emit light? Direct and GI I guess?
i notice the lighting, specular and GI passes are looking good, but the reflection one is noisy.
Hey guys I found the solution!
It’s just the settings I used all the time to avoid fireflies in glossy reflection even without Phoenix (I just forgot to use them in this scene):
In the V-Ray color mapping I just check on Sub-pixel mapping and I clamp the output to 5 or 8.
I’m pretty sure it will work for you too Lasse. It happen all the time when there are very bright sources being reflected, be it from an HDR environnement or light or PhoenixFD fire. Explosions are very bright sources that’s why.
before:
after:
Both settings are needed cause here is what happen when you use only one:
Subpixel mapping only:
And clamp only:
I also tried lowering the max ray intensity setting in the Global switches cause in the docs they say: “Its effect is similar to the Subpixel mapping + Clamp output options of the Color mapping section, but the Max ray intensity is applied to all secondary (GI/reflection/refraction) rays, as opposed to the final image samples. This allows fireflies to be effectively suppressed but without losing too much HDR information in the final image.”
But even lowering it to 0.001 )no subpixel and no clamp) does not work in this case, I am loosing all light on the tank and still got all the fireflies.
Hey Jstrob
have you tried comparing the overal look of the frame when enabling subpixel mapping?
In my tests, enablin subpixel always changes brightness of the scene in some parts.
But perhaps the very high clamp value goes against that and levels out the differences???
I almost always use it and I never noticed a change in the overall look, just a change in the highlights which become less bright. But you can make them brighter by rendering all the needed raw elements and adjusting in comp.
Any updates for this issue?
I’m currently working with the scene where I need to get reflections and Phoenix lighting working.
I’m still doing simulation tests, but after a week or so, I should start to render passes out for comp.
Clamp and sub-pixel mapping might help, but I wouldn’t like to go that way yet.
Hi,
I have another shot here (my missile launcher) where the light from the missile fire on the wall and objects around (which are matte objects) is very noisy and too long to render. using clamp and subpixel doesn’t correct it. I think I will just fake it in a separate pass using an omni light animated to follow the fire.
If anyone find a fix for this please tell me.
In fact I was using matte objects to create light from fire pass to comp on live footage. But I noticed if I use a black material override instead, I get a lot less noise. Still noisy but I will use the denoiser to see.
Good find! I’m afraid that until we make the Fire lights native to V-Ray, there will always be similar situations, and workarounds such as this or reducing the light resolution, the light power on scene options or experimenting with the light subdivisions would be the way to go.
In fact the biggest problem with lighting on objects (from PhoenixFD) when the objects are matte object (from their prop in vray prop) is the render time. It was more than 8 hours a frame and still very noisy. So creating a separate pass with a black vray material on regular objects was way faster to render ( 50 minutes a frame down from more than 8 hours on dual xeon E5-2640 v3).
And so raising light subdiv would not work, reducing light power on scene would not work cause in my scene is was alreayd pretty dark. I am trying lowering light resolution just to see but even at 0.01 (I was at 6 or 7 before), there is still noise.
Now I had a problem with too much noise/artefact and very slow render in my light pass even with the black shader override. I even had some bucket with noise and some other that were ok.
but I just change the volumetric mode to the volumetric geometry mode for my light pass and now it works lik e a charm and renders super fast.
before (the result of some render region experiment avorted because it was too slow):
and the vol geo mode:
:
