Lighting with HDRI and Temperatures

[padre.ayuso]

Does anyone have a good tutorial to read on how to light an interior scene using HDRI and at the same time be able to tweak the temperature of the HDRI directly in VRay? I'm sure there is a way, but have not worked it out yet. Maybe it is an odd request, but I felt like I should ask.

[Sbrusse]

What about changing temperature in the VrayCam?

[vlado]

You could pipe the HDR through a ColorCorrection node and tweak its hue there.

Best regards,
Vlado

[padre.ayuso]

What about changing temperature in the VrayCam?

That would be a negative. If your interior lights have a temperature value of 3000, then once you change your camera values you have to start messing up with the interior values and there is more lights in the interior than just the sun (being only one light).

Vlado's idea is good, I have tried Color Correction in RT GPU before but somewhat unsuccessful. I think I'll give it a go today and let you guys know on this thread how that goes.

[padre.ayuso]

You could pipe the HDR through a ColorCorrection node and tweak its hue there.

Best regards,
Vlado

Hi Vlado,

So just tried the Color Correction tool with the GPU RT. The only thing that I'd ask if at all possible is to enable or make it work slightly differently. The only tools that work and seem to change the HDRI on RT GPU is the Advance Controls of RGB, not the overall Saturation and Hue Shift. If I can Desaturate from Color Correction it would be easier than trying to get the right values of RGB in Advance. Then again, I think it was Grant Warwick that mentioned that Hue Shift and Saturation in Color Correction map don't work properly... Just mentioning it here to see if something can be done about it. Thanks!

[chriserskine]

i've warmed and cooled hdri's by using a vray comp map, hdri in one slot and a vray color set to temperature in the other.

[padre.ayuso]

i've warmed and cooled hdri's by using a vray comp map, hdri in one slot and a vray color set to temperature in the other.

Interesting, I'll try that. But if I'm not mistaken, the Comp Map handles 8 bit colors? I may be wrong on this, but I read it somewhere that it handles white as 255 in RGB, which is an 8bit amount, right? If so, when you put an HDR image in one slot, does it get "converted" into an 8bit image? Agai, I'll try it on my next scene, but just wondering how does that work?

[chriserskine]

I didn't realize vraycomptex wasn't float.

I don't normally do it. but i think i was setting it to multiply.

worked pretty well for what i needed.

[padre.ayuso]

OK, will let you know how it goes for me. Here is the article I was referring to:

https://www.vray.com/vray_for_3ds_ma...ycomptex.shtml

[DPS]

How about adjusting the HDRI in an output map. Adjust the white point of the individual RGB channels and leave the gamma in tact. This is the same as adjusting the exposure per RGB channel and is how the white balance works in a digital camera.

I think it works in RT.

Also if you're experiencing saturated colours using HDRIs, I often see people having this issue when they don't adjust the white balance in camera as Sbrusse suggested. You'd usually adjust the white balance when using a real camera.

[Vizioen]

So according to the manual the VrayComptex isn't float? Question: is the native 3dsmax Composite map float?

[vlado]

So according to the manual the VrayComptex isn't float?

Of course it's float. Where in the manual does it say otherwise?

Best regards,
Vlado

[Vizioen]

Of course it's float. Where in the manual does it say otherwise?

Best regards,
Vlado

I was just quoting padre.ayuso. The link (https://www.vray.com/vray_for_3ds_ma...ycomptex.shtml) he mentioned, talks about 255 values, which is 8bit, so I understand the confusion.

[padre.ayuso]

Of course it's float. Where in the manual does it say otherwise?

Best regards,
Vlado

Thanks Vlado, yes, that was my confusion, because apparently white point was set at 255 so I was wondering. But if you say it is float, then that clears it up.