Help Topic: OCIO and LUT

[stevejjd]

That's really helpful- thanks sharktacos

[PIXELBOX_SRO]

Nice post!
In my opinion the LUT implementation in the VFB doesnt properly work. I will post some samples tomorrow of what i mean.

[OPEN_RANGE]

Still following this thread. I do not have any of the technical knowledge and expertise that is being discussed. I do want to be able to use the filmic tone mapping. Right now I'm using it in the free version of Fusion. It's nice because it has the controls for shoulder and toe (shown in the earlier thread pos). Lets one compress highlights AND lift shadows.But that has one gotcha, max image size allowed is 3240 x 2160 (4K, UHD). I can't justify the cost and complexity of a full version of Fusion just to apply tone mapping.

I was hopeful that applying filmic LUT from this thread to the VFB might be a solution. I have applied it successfully and it looks good. Having the controls over the filmic tone mapping, like available in fusion, would be nice but maybe not required. My trouble is that I can't seem to sort thru the file format differences to get it applied in pshop correctly.

I'm working in Vray with linear workflow. Saving renderings as 16bit/half float .exr files



Rendering in VFB with no LUT or other controls


Rendering with filmic LUT


Rendering with filmic LUT and Convert to Log color space unchecked. This is what it looks like when I apply the filmic LUT to the rendering.exr in pshop

[OPEN_RANGE]

Had to make second post to include following attachements

EXR opened in pshop



EXR in pshop with filmic LUt applied. this is what I hope to sort out. How to apply the filmic LUT in pshop correctly




I hope this is not too much for this thread or a hijack of it.

[sharktacos]

Do be aware that Photoshop does not play nice with EXR nor with LUTS. This is because it is primarily a tool developed for print. You may get better results using things like After Effects or Premiere. Personally I like to work in Nuke since it works in linear straight out of the box.

[davision]

Does anyone know how to get the OCIO plugin to work wtih After Effects. I have it running but I can only point to one ocio config file. The pdf manual makes it look like you can choose between a set of OCIO configs (spi-anim, spi-fx, etc.).

[stevejjd]

You can get Nuke for free https://www.thefoundry.co.uk/products/non-commercial/

Download and use the filmic tone mapper all for free.

The Exr beauty pass you are saving does not have the frame buffer tone mapping options burned in.

I think you have to open the VFB and Hold Click the Save Icon and chose current channel - I think this will Burn the Filmic Tone Mapping into the file. I havnt confirmed this yet but Im sure there is a way to Burn all the Color options from frame buffer to the saved file. I also want to experiment with Cebas PSD manager which can send the passes to photoshop with the correct order and blending mode and also collapses the color controls into a LUT adjustment layer.

[PIXELBOX_SRO]

Hey guys,

i ve promised some images about the vrays LUT implementation which i find to be a little unfinished (i dare to say)

below are two comparison sets of images.
Left image is always from CORONA IMAGE EDITOR while the right one comes from VRAYS FB
Please notice that when you load the EXR in both, they both seem a little different (probably because the process the EXR different way) and the one in VFB needs to have the sRGB button checked to be viewed properly (if you render linear).....here, vray is more contrasty and corona is a less
After application of LUT in both, the situation changes - Corona is brighter and more contrasty, the Vray is a littel washed out and whats more....YOU HAVE TO UNPRESS THE sRGB BUTTON!!!!!
It took me half a half a day to find out that i need to uncheck the sRGB button in order to view the LUT the right way.

Anway, i am really missing some smart LLUT browsing and opacity control for the LUT.

Why is it necessary to unpress the sRGB in VFB?
What do you think is causing both render engines to display differently when its the same EXR and the same LUT?

[OPEN_RANGE]

Stevejjd,

Thanks for that. I had looked at that option but the gotcha is that I need to do commercial work. So the free version is not an option for me. As you have stated, the free version of Fusion handles this very well with a filmic macro add on. I find the Fusion tone mapper controls (shown in your post #10) to be very useful, especially for getting more detail out of shadows. The gotcha is the free Fusion will only allow saving images of max size 3240 x 2160. Full verisons of both Nuke and Fusion are too $ for a one person freelance operator like me.

Martin,

Agree it wold be desirable, maybe even a requirement, to be able to apply the filmic tone mapper as a separate operation (versus baking in) so that one could control the opacity of it. Having the other controls like mentioned above also very useful

[piotrus3333]

OPEN_RANGE

it looks from the screenshots like you are saving your exr's with wrong gamma. don't know about newer max but 2015 saves exr's with wrong automatic gamma ("recommended" setting).
and go for 32bits. than just grab cube file with all the frame buffer corrections and it will contain LUT as well (so probably also OCIO)

[OPEN_RANGE]

Piotrus, thanks for your reply. It's a bit hard to make out, but in the top most screenshot you can see that I do have the "automatic" checked in the save file dialog.

i can "grab" the file from the VFB with the LUT applied, but I am trying to find how to save the render and then apply the filmic LUT in pshop. I am starting to get that I may neeed to incorporate using After Effects for this. Have not tried that yet. Have used free Fusion and that works but max resolution is limited. Full version of Fusion or Nuke too $ for my limited needs.

[piotrus3333]

Piotrus, thanks for your reply. It's a bit hard to make out, but in the top most screenshot you can see that I do have the "automatic" checked in the save file dialog.

automatic does save wrong gamma to exrs in 2015. I can safely assume that 2017 is no different. I was refering to just that screenshot, with save file window.

[piotrus3333]

and by grabing .cube file I ment saving LUT from VFB.

[OPEN_RANGE]

I am a bit confused (maybe more than a bit). I never heard that max saves to the "wrong" gamma if using automatic. My understanding is that, using vray default linear workflow, having automatic checked in the file save dialog results in getting the Gamma 2.2 baked in to the saved .exr. I think that's how it's supposed to work and how it has worked in 2015, 2016 and now 2017? If 'override is checked" then it can be saved with Gamma 1.0.

I don't understand the need to grab the .cube file or save LUT from the VFB? The .cube file is saved in a directory on disc so I just use the same .cube file from that location and put it into the VFB and then also add it in post in pshop. Thus, no need to "save LUT from VFB"?

My level of expertise with this stuff is limited. I like being able to apply the filmic tone mapping. I'd like to be able to control it's settings and strength. I'm trying to figure out the best way to go about that for my circumstances.

[sharktacos]

I am a bit confused (maybe more than a bit). I never heard that max saves to the "wrong" gamma if using automatic. My understanding is that, using vray default linear workflow, having automatic checked in the file save dialog results in getting the Gamma 2.2 baked in to the saved .exr. I think that's how it's supposed to work and how it has worked in 2015, 2016 and now 2017? If 'override is checked" then it can be saved with Gamma 1.0.

If the 2.2 gamma is baked into the EXR this makes it no longer a linear file (linear means 1.0) and as a result all the math in Nuke will be incorrect. So if you are trying to maintain a linear workflow, as done in a VFX pipeline, then it is defintly "wrong" to bake the sRGB gamma transform into the image. In a linear pipeline the 2.2 gamma is how the linear image is viewed on a sRGB monitor. In Vray this "view transform" is a little button on the VFB. In Nuke there is a similar view transform.

If you want to just edit the image with a non-linear workflow in Photoshop, in a manner similar to how one would edit an 8-bit PNG photo, then you could bake the view transform (the 2.2 sRGB gamma, or the Filmic LUT, etc) into the image. But then you are no longer working in linear. Photoshop really does not work well in linear anyway, and I would frankly not expect it to give accurate results with linear EXR files and LUTS.