Tone Mapping

[glorybound]

Reinhard, in V-Ray, seems to be pretty common and highly used. However, isn't that tone mapping in the renderer, which isn't the best place to do it? When I set my V-Ray color mapping to Reinhard, clamp the output, and check Sub-pixel, my render times is around 2 hours. It's a very flat and dull render, but I can tweak that in post, and I might be limiting myself. When I stay pure linear (don't clamp or check Sub-pixel and with Linear multiplier) my render time jumps to 11 hours and I get fire flies with blown out areas. I get why; V-Ray is dealing with the bright spots. I am not too concerned with the blown out areas; tone mapping in post should solve that, but the fire flies are problematic. I do have Max ray intern enabled, but I am still getting them. I understand that their is a couple schools of thought, but what is the best way to work? I am working with real camera settings and real light settings; I can better wrap my head around things staying with real settings. Should I simply render darker, saving at 32 bit exr and tone mapping in post, or are their inherent issues with this, too?

BTW... I do architectural stills. My question was initiated by a tutorial I just watched (https://vimeo.com/ondemand/tonemap)

[3LP]

Can you show a crop of the type of fireflies you're dealing with?
Stan

[glorybound]

I have dealt with them, but for next time, I'll show what's going on. However, what's with the extreme render time difference?

[glorybound]

I rendered the est 11hr linear and it actually only took 2 hrs, which is the same as the Reinhard render with clamped and sub-pixel checked.

[voltron7]

What kinds of light sources are you talking about here?

[glorybound]

All kinds, I guess. I have VRay Sub/Sky, some IES, and some VRay lights.

[CAPTURE_MM]

So your main problem are the fire flies, right? To which value did you set the Max ray intensity? You might have decrease the value further. Other than that, avoid small concentrated, overly bright light sources.
Also check to see if your material samples are set high enough. Remember that with "Divide subdivs" enabled and a high Max subdivs AA value, your material samples will get reduced considerably and you might end up with too few samples per primary ray.
I'm not sure if higher light samples will also help alleviate this issue, but you could try that, too. It will only help if these are true light samples and not merely shadow samples.

[CAPTURE_MM]

One more thing: based on our experience, the specular contribution of bright lights is often causing fire flies. Consider reducing its specular contribution per light or turn off the specular contribution alltogether and render only true reflections of visible area light sources.

[glorybound]

To which value did you set the Max ray intensity? You might have decrease the value further.

I was increasing it... oops. I did look for documentation on the Max Ray intensity, but I didn't find much. I'll try to lower it.

[glorybound]

So, un-tick specular for the lights?

One more thing: based on our experience, the specular contribution of bright lights is often causing fire flies. Consider reducing is specular contribution per light or turn off the specular contribution alltogether and render only true reflections of visible area lights. sources.

[CAPTURE_MM]

So, un-tick specular for the lights?

Either that, or lower the specular contribution in the "Options" rollout of a vray light source. I'm using VRay for Maya, but I guess the same option should be available in 3ds Max, too.

[Deflaminis]

One new feature of Vray 3 that doesn't get mentioned much (but is pretty awesome) is on the corrections controls in the "Exposure" rollout you can adjust the burn rate there now, as a post effect. So... can render linear and preview Reinhard and make all sorts of adjustments based on both combined with the Bloom/Glare. Pretty sweet.

[glorybound]

Yes, I have played with this and it does it well, but it's very destructive.

One new feature of Vray 3 that doesn't get mentioned much (but is pretty awesome) is on the corrections controls in the "Exposure" rollout you can adjust the burn rate there now, as a post effect. So... can render linear and preview Reinhard and make all sorts of adjustments based on both combined with the Bloom/Glare. Pretty sweet.

[Deflaminis]

I guess I always throught Reinhard was destructive as well. Maybe they give different results because one happens at render time and one happens in post. Have you noticed any weirdness?

EDIT: Spelling

[Lupaz]

Reinhard, in V-Ray, seems to be pretty common and highly used. However, isn't that tone mapping in the renderer, which isn't the best place to do it? When I set my V-Ray color mapping to Reinhard, clamp the output, and check Sub-pixel, my render times is around 2 hours. It's a very flat and dull render, but I can tweak that in post, and I might be limiting myself.(https://vimeo.com/ondemand/tonemap)

This seems to be like a good workflow. I use this, except with linear instead of reinhard. Sub-pixel mapping was doing all the necessary adjustments without needing a "burn value" parameter.
BUT! A week ago I went nuts with a scene because the brightness was messed up. I then realized that it was the sub-pixel thing.

I wonder if there could be a way to control this sub-pixel mapping to manage burned areas, as opposed to work with rehinhard or completely linear, which never solved the AA artifacts on extreme contrast areas.