Noise in Vray Disc light

[Furnace]

Hi,
Someone her has helped me set-up some VRay disk lights to act as headlights to create some headlight mist/fog, reference to what I'm trying to do attached.
Does anyone know why I'm getting the extreme white noise dots?

Thanks,
Elliot

[tashko.zashev]

Try to rise up the "probabilistic lights" parameter and see if it helps.

[Furnace]

Hi Tashko,
That didn't work, noise looks the same, please see attached.

Any other ideas?

Thanks,
Elliot

[Svetlozar Draganov]

Then it is best to send or attach a simplified version of the scene for investigation.
Let us also know the exact version/service pack of V-Ray and 3DSMax.

[alexyork]

Try turning off Probabalistic Lights entirely. In my experience with scenes with many lights it is a total nightmare to make it work properly.

But this to me looks like crazy overbright specular.

[vlado]

Try turning off Probabalistic Lights entirely. In my experience with scenes with many lights it is a total nightmare to make it work properly.

Can you get me such a scene? I'd love to see where it fails.

Best regards,
Vlado

[alexyork]

Can you get me such a scene? I'd love to see where it fails.

Best regards,
Vlado

I can try. It was very noticeable on a particular project, which is under very strict NDA unfortunately. Basically it was just a regular exterior scene with something like 100+ lights and with PL enabled I was getting terrible sampling issues and not able to properly control light sample quality as I normally like to (per light). I just found it way better without it enabled.

[Joelaff]

Are the lights going through the refractive headlight glass? Maybe try excluding the glass from the lights and see if that helps?

[vlado]

I can try. It was very noticeable on a particular project, which is under very strict NDA unfortunately. Basically it was just a regular exterior scene with something like 100+ lights and with PL enabled I was getting terrible sampling issues and not able to properly control light sample quality as I normally like to (per light). I just found it way better without it enabled.

Ok, so it will be a perfect study case if you can get me something similar. I definitely want to make this work in all situations.

Best regards,
Vlado

[Morbid Angel]

All the fancy stuff aside, you'd probably better off using simple spot lights.

[Joelaff]

We find probabilistic lights seems to generate significantly more noise in all of our tests, and no speed improvement. So it is off by default here.

I am with Dmitry, spotlights for the car headlights. Just throw a projector map on there to get the needed light pattern on the ground.

[vlado]

We find probabilistic lights seems to generate significantly more noise in all of our tests, and no speed improvement. So it is off by default here.

Well, it's the opposite of my tests - and precisely why I want to see yours. It also gives me a context to test any further improvements in that area.

Best regards,
Vlado

[Joelaff]

When we are done with this project in a couple weeks I will see if I can get something together. The problem is that it is usually on a big complex scene that we can't send out.

On simpler scenes it doesn't seem to make any difference. Of course sometimes there are fewer than the specified number of lights, in which case I would assume it is ignored.

I wonder if it has to do with IES lights. Our current project has everything in the shot animating, as well as the camera walking backwards from inside to outside. The inside is terribly slow and/or noisy. The outside fast. Irradiance maps don't seem to be accurate enough for the project, and take almost as long to generate and then render as brute force. The interior has a number of IES fluorescent type lights, and I am pretty sure they are contributing to the slowdown.

[vlado]

Ok then, whatever you can throw my way is welcome Thanks!

Best regards,
Vlado

[Syclone1]

The scene did the same thing with the disk lights and with IES as well. Ill make a new scene for you Vlado and send that off.

-=Edit=- file sent with just the fog and lights