Help Topic: OCIO and LUT

[Rens]

Ok to test the Filmic OCIO file attached is the zip from the first link with the vray specific lines commented out, just unzip it in a folder and load up config.ocio in the VFB (disable the sRGB button in the VFB and switch the LUT/OCIO button to OCIO, load the file -- see the attached image).

All in all it's a pleasant look for a lot of things, not for everything though. Definitely something to play with.

[stevejjd]

Cool, at least now we can have a play and see if its good.

[Rens]

So to recap without all the technical details:
This is a colour correction for your rendered image, like you could achieve with the VFB controls or in post (PS/Nuke/AE/etc.) as well, which can give nice results in certain situations.

[stevejjd]

I really like it already ~ Vlado doesnt have to code a color Mapping engine ~ Lele wont be tortured, The VFB wont become Nuke ..... looking good

[Rens]

Yeah it's a very pleasing look, especially for archvis I can imagine!

[stevejjd]

I think Im perfectly happy with this. No need to bother Vlado. This is fantastic. Thanks Rens....they shall give you the medal of honor.

@Rens have you tried downloading and testing the OCIO profiles from http://opencolorio.org/downloads.html

Do you know how to use and test them and what they are? Are they camera and film types?

Man Im really happy! ~ I am living proof that The squeaky wheel gets the grease

[kosso_olli]

Thanks Rens and 1funk for trying this out! Just tested it on an interior, looks good. However, there is no way to get these images into Photoshop for example. The OCIO transforms are not baked into the render, the ctrl+c trick doesn't work (I only get a very washed out image into PS that way). PS itself doesn't support OCIO, of course. Cause Adobe.

Left sRGb, right filmic in high contrast mode.

[vlado]

However, there is no way to get these images into Photoshop for example.

You can always copy/paste from the VFB. Now there is a button for this in the VFB toolbar (before there was only the Ctrl+C shortcut). We are currently thinking of how exactly to expose the functionality to save those things.

Best regards,
Vlado

[kosso_olli]

Yes, I did that. But the image in PS is really washed out afterwards. Don't know why, but it has something to do with the applied OCIO.

[Ihno]

Try to set the proof to monitor rgb.
Ps adds a gamma curve to all 32bit images.
You can also use the exposure effect with a gamma of 0.45.

[Oleg_Budeanu]

it would be cool if someone can make a short tutorial on how to use that for previewing image and use that profile in NUKE or Fusion afterwards.

[stevejjd]

Found a small but interesting article here
http://www.xuanprada.com/blog/?category=color+space

[yolov]

Do you mean the LUT/OCIO that you can export from the VFB and then use it in NUKE (for exampe)?

[^Lele^]

I really like it already ~ Vlado doesnt have to code a color Mapping engine ~ Lele wont be tortured, The VFB wont become Nuke ..... looking good

I agree, thanks Rens.
What i really didn't want, was for all the issues arising from the abuse of CC approaches which aren't quite well understood to fall on my lap (or our Support's!).
Have a ball deciding the subjective qualities of befores and afters, as long as when things do not work, as intended or at all, we don't have to debate Filmic all over again: we (well, surely I) did tell you before.
Equally, for every time it'll do what you want, feel free to curse my way: i have a feeling i won't have my ears ringing all that much anyways. :P

[sharktacos]

Some things should be set straight here:

- Saying that it can be done in post is completely missing the point. The entire point of this is that you do not do this only in post. That you view your scene through better camera response already when setting it up, so you don't make mistakes in setu process, such as using too faint light sources that will cause less light bounces, and such. The point of this is viewing data that renderer feeds you through a curve that makes the data more resemblant of how human eye perceives real world captured through photography. The point here is to prevent you working blind the entire time in 3d package, and hoping you will fix it all in post.

- Yes, it is a LUT, technically, but LUTs can not access more than 0-1 range, so that LUT needs to be fed the source image in a Filmic Log base, instead of sRGB base, so it can access entire exposure range, not just 0-1. And this is something V-Ray can not do. V-Ray can load the Filmic Log base OCIO, but it does not allow you to use OCIO and LUT at the same time.

- It would be very unfortunate to implement ACES in a way that it exposes all of the filmic tone mapping controls. All the toe/shoulder and slope parameters. This would confuse the hell out of users, especially the new ones, and would kill the feature almost instantly. The simplistic way it is implemented in Blender is a lot better example.

I would recommend this video. It's more professional and technical than BlenderGuru's video. It has a lot less inaccuracies and explains it a lot better: https://www.youtube.com/watch?v=vKtF2S7WEv0

Excellent summary. I want to return to your statement about the difference between OCIO and LUTS. So if the idea is to make the lights react in a way that is more like a camera, simply having a LUT would not work because it is only affecting the 0-1 range, and you need to have an OCIO instead to affecting the full range?

If that's true it would be good to be able to have both an OCIO and LUT applied in the VFB. Would this be a difficult thing to implement? I guess I had assumed it already worked to have both on in the VFB.

Note: I have zero interest in creating a "look" in the VFB and am only interested in getting the lights to respond like they do in a camera, which does not happen in sRGB.