Vray Luts look wrong

[hermit.crab]

This only works as long as you do not save the image. The written output is totally messed up with LUT baked into the image.

Seems to work fine on a simple test. Do you have an example to share?

[kosso_olli]

Sure. Here is an image in the VFB along with the settings, and an image of the saved EXR from the VFB opened in Photoshop. It seems like double-gamma.
This was tested with a variety of LUTs, they all behave the same.

[Donfarese]

That's interesting, I haven't saved an image out yet. I just copied from VFB and pasted in my comparisons.

[hermit.crab]

Sure. Here is an image in the VFB along with the settings, and an image of the saved EXR from the VFB opened in Photoshop. It seems like double-gamma.
This was tested with a variety of LUTs, they all behave the same.

For linear image formats, you need to disable the Display Correction in your image viewer (i.e. in Nuke, the image's Color Space should be set as sRGB).

[kosso_olli]

Well, thanks Photoshop. There is no way to do it there.

[piotrus3333]

nuke, fusion, vray - everything works the same as you have more options to make it work the same.
its Corona that is different: when you prepare a lut for Corona you need to put it in a gamma sandwich.
and its 2.2 and not sRGB.

edit: if Corona devs say it’s sRGB not 2.2 I guess I missed that detail. sRGB sandwich in that case.

[piotrus3333]

I'm sure this is something I'm doing wrong, but when I add Luts to other renderers I get what I expect and similar results. But when I add the same Luts to Vray I get very odd results. I attached an image showing the issue with just one Lut and with Corona since Chaos owns both. See what the Lut does to the Vray render compared to what it does to the Corona render. This Lut happens to use log space, if that matters.

this particular lut was made for Corona. there should be _lin version where you got this one. if not let me know which one is it.

[Donfarese]

this particular lut was made for Corona. there should be _lin version where you got this one. if not let me know which one is it.

Hi piotrus3333, Thanks for the input. The LUT is mP_CoronaLogUE3Filmic_5.35_64.3dl. It uses log space. it would be great to have this in Linear and in non Log space to test with Corona and such.

[piotrus3333]

Hi piotrus3333, Thanks for the input. The LUT is mP_CoronaLogUE3Filmic_5.35_64.3dl. It uses log space. it would be great to have this in Linear and in non Log space to test with Corona and such.

UE3 Filmic LUTs:
https://forums.chaos.com/forum/chaos...17#post1140217

mP_Lin2UE3Filmic_468_5.35_32.csp is mainly for Photoshop (or Affinity Photo). PS in 32bit mode only obviously. uses CineonLog shaper. csp format is not very popular but this lut will work everywhere where csp is properly supported.

mP_CineonLog2UE3Filmic_5.35_64.3dl is for everything else (e.g. VRay with Log option ticked).

mP_CoronaLog2UE3Filmic_5.35_64.3dl is Corona only. with apply lut in log space on. it is still CineonLog to UE3 Filmic but with Corona's gamma backflips.


what do you mean by "non Log space"?

[Donfarese]

UE3 Filmic LUTs:
https://forums.chaos.com/forum/chaos...17#post1140217

mP_Lin2UE3Filmic_468_5.35_32.csp is mainly for Photoshop (or Affinity Photo). PS in 32bit mode only obviously. uses CineonLog shaper. csp format is not very popular but this lut will work everywhere where csp is properly supported.

mP_CineonLog2UE3Filmic_5.35_64.3dl is for everything else (e.g. VRay with Log option ticked).

mP_CoronaLog2UE3Filmic_5.35_64.3dl is Corona only. with apply lut in log space on. it is still CineonLog to UE3 Filmic but with Corona's gamma backflips.


what do you mean by "non Log space"?

Thanks for all the info, what I meant is the corona version, but where you don't need to enable log space.

[piotrus3333]

Thanks for all the info, what I meant is the corona version, but where you don't need to enable log space.

what is wrong with log? apply lut in log space option moved into settings part of UI? that was in 7 I guess. in Corona 8 it is back where it should be.

it is possible in Corona (at least with cube format I think) but it would require pretty big LUT to retain precision.