Save EXR from VFB

[glorybound]

Why doesn't the VFB save the VFB color adjustments? It get's me every time and it kind of defeats saving all the elements together from the VFB.

[jackieteh]

Great question...i am here to ask the same question today
Hoping anyone or chaos group could answer this, thank you.

[vlado]

OpenEXR files are by definition intended to be in linear space without any color corrections.

Best regards,
Vlado

[glorybound]

Okay, good to know. What would the best way to save the VFB color grading in 32 bit, with all the elements?

[vlado]

Okay, good to know. What would the best way to save the VFB color grading in 32 bit, with all the elements?

This might not always make sense. Many color corrections (highlight burn, LUT etc) clamp the result or otherwise modify it in a way that makes 32-bit output somewhat pointless. A better approach would be to export a LUT file with the color corrections and apply it on the exported linear EXR output.

Best regards,
Vlado

[glorybound]

Gotcha, thank you!

[dans]

@Vldao AFAIK using the current V-Ray LUT export (.cube files) will not produce the same result as the VFB for color values that go beyond the 0 to 1.0 range, because the cube file is written for the default domain 0..1.

Daniel

[vlado]

@Vldao AFAIK using the current V-Ray LUT export (.cube files) will not produce the same result as the VFB for color values that go beyond the 0 to 1.0 range, because the cube file is written for the default domain 0..1

Hm, I have to check that.

Best regards,
Vlado

[jackieteh]

If vray can save out all the correction into EXR like corona is great right?

[vlado]

If vray can save out all the correction into EXR like corona is great right?

Nope. EXR files are supposed to represent the raw render without color corrections. We will enable the writing of the color corrections when saving to 8-bit files (JPG, PNG etc) but not for EXR files.

Best regards,
Vlado

[LudvikKoutny]

I would welcome the option for HDR formats too, honestly. Cases where color corrections completely clip off the dynamic range outside of 8bit are actually quite rare. So if you have image, which you have set up to look very nice right in the VFB, and you just want to take that result you already like in Fusion for example, if you then decide to touch exposure in fusion, to lower it for example, you won't get clipped ugly gray flat areas on highlights as long as you haven't used a combo of color corrections which completely clips the range.

Of course, it would still make sense to keep such option off by default.

[jackieteh]

Nope. EXR files are supposed to represent the raw render without color corrections. We will enable the writing of the color corrections when saving to 8-bit files (JPG, PNG etc) but not for EXR files.

Best regards,
Vlado

Now i understand why vray turn off the option. but it is hard to explain to those who using corona in my company

[jackieteh]

I would welcome the option for HDR formats too, honestly. Cases where color corrections completely clip off the dynamic range outside of 8bit are actually quite rare. So if you have image, which you have set up to look very nice right in the VFB, and you just want to take that result you already like in Fusion for example, if you then decide to touch exposure in fusion, to lower it for example, you won't get clipped ugly gray flat areas on highlights as long as you haven't used a combo of color corrections which completely clips the range.

Of course, it would still make sense to keep such option off by default.

What is HDR format mean? do vray got this option now?

[Fat Tony]

Nope. EXR files are supposed to represent the raw render without color corrections. We will enable the writing of the color corrections when saving to 8-bit files (JPG, PNG etc) but not for EXR files.

Best regards,
Vlado

yes please, and also would be really really handy to enable writing LUT in 8-16 bit files directly from VFB. Any previews we make in VFB, atm we have to print screen instead of proper save when using LUTs

[LudvikKoutny]

Hi,

sorry to necromance this thread, but I just found one thing I can not understand.

Chaosgroup seems to be very protective about keeping high dynamic range image formats output of out V-Ray linear, hence the reluctance to introduce ability to output images with LUT baked in. So I respected that and relied on that being the case. I've just now saved EXR image that has been rendering for hours, and I had highlight compression in exposure controls of VFB enabled just for preview purposes. I've just saved the EXR expecting it will be saved linearly, closed the VFB and opened different scene. To my surprise, the EXR was saved with the highlight compression baked in, effectively negating all the time I've spent rendering the image, as I needed HDR data to apply glares.

I really do not understand it. Why can we have an option to ruin our HDR images with highlight compression and contrast features, but can not do so with LUTs. Shouldn't it be all or nothing? This mixed behavior adds to the confusion.