HDRI and firelies with vray 3.30

[t3dm]

Hi all,

Got a scene that has fireflies on the reflections... not had to deal with this for a while.

The render is at 4000px (smaller and you don't really see it as bad)

The render only has the HDRI active at the moment (while I trouble shoot). I am using global sub divisions... which are low for speed, but even when I go local and with the HDRI subdivisions at 64 the fireflies are evident and buckets are slowing to a crawl over the fireflies.

I have tried various HDRI's too and they are evident in them all.... used max ray intensity to reduce. The only way I have found is to get rid of the them is to 'treat glossy rays as GI' set to 'always' in the material...

usually if I enabled Clamp output and sub pixel mapping it would sort the problem... that doesn't even work though!

LC/BF GI....

[vlado]

Do these go away if you disable the "Reflective GI caustics" parameter in the GI settings? You may need to switch the rollout to "Advanced" view to see the option.

Best regards,
Vlado

[t3dm]

ahhhh.. away to check as I we normally hide the glass at the windows from GI... which check this and re render...

[t3dm]

alas.... not worked..

i'm pretty stumped on this.. tried most of the usual suspects in this kind of problem....

[vlado]

Ok then I will need the scene somehow to figure out what's wrong.

Best regards,
Vlado

[t3dm]

It's a heavy one.. I haven't really working with the new vray 3.3 settings.. so reading up on this. It's a typical HDRI through window's issue, I would normally have around 64samples on the hdri then use adaptive sampling and noise threshold to remove.

I will upload the scene and wetransfer to you.. what's the best email to send it to?

[vlado]

I will upload the scene and wetransfer to you.. what's the best email to send it to?

It's best to send it to support@chaosgroup.com and mention this thread.

Best regards,
Vlado

[Morbid Angel]

Check that the material on the geometry which gets speckles is not ggx, if it is try switch it to blinn.

Also generally speaking, small bright objects, like point spheres, or any small geometry with self illumination may cause this since its hard to indirectly trace that kind of source. See if you have any of that in your scene.

[t3dm]

yep... I was worried with was something scene dependent.. then checked another project we were working on and I got the same.....

so reset back to defaults and I think I have found out that filter maps was ticked but filter for GI in the image sampler was not checked.... doing tests at various test now... looking good!

[t3dm]

actually... nope... that didnt work at higher resolutions... 4500px plus!

[Morbid Angel]

Is your hdr high res with some kind of hot spot like a sun? its also possible if you have a dot in the hdr that's really bright it will cause this.

[t3dm]

yep.. it's a high HDRI.. we take our own... but tested it with cg_source and Peter Guthrie once we have too.... it's something that I have noticed come back in, as before if we had this we would clamp or use max ray intensity to remove (though I would always try and relight the scene first...

it's a challenging visual.... and we have very little time to complete, so now using this as a R=D project now.

If I put up the dmc max subdivisions to over 24 and the MSR to 48 I can remove the firefiles... but for a 5000px BF render it will take 27hrs to render.. we were getting around 7hr before... so not really going to cut it for the type of work we do... obviously we can selectively render some of the problem areas...

I'll post the file shortly.

[t3dm]

...here is the HDRI screengrabs....

[svetlozar.draganov]

...here is the HDRI screengrabs....

Did you send us that scene to support@chaosgroup.com?