Page 1 of 1

OCIOFileTransformViewLut broken (+ some lut ideas)

PostPosted: Wed Sep 09, 2015 6:00 am
by Theodor Groeneboom
-

Re: OCIOFileTransformViewLut broken (+ some lut ideas)

PostPosted: Thu Sep 10, 2015 8:43 pm
by Rony Soussan
Couldn't agree more.
I hope to take all this up once 8 is out, as the whole lut workflow is a bit dated. It works, but needs a bit more effort than it should to get the results you need.
With BMD having DaVinci and all that, I am optimistic about that workflow getting some love moving forwards.

Re: OCIOFileTransformViewLut broken (+ some lut ideas)

PostPosted: Fri Sep 11, 2015 12:02 am
by Chad Capeland
Rony Soussan wrote:Couldn't agree more.
I hope to take all this up once 8 is out, as the whole lut workflow is a bit dated. It works, but needs a bit more effort than it should to get the results you need.
With BMD having DaVinci and all that, I am optimistic about that workflow getting some love moving forwards.


I think the buffer LUT works fine, it's just such a pain to get it set up. So many clicks...

Re: OCIOFileTransformViewLut broken (+ some lut ideas)

PostPosted: Fri Sep 11, 2015 11:34 pm
by Rony Soussan
exactly, and appending multiple luts, and just doing a basic black point gamma check is a lot more work than it has to be.
I ultimately end up using fileLuts and gamut nodes in the flow to manage that stuff.

Re: OCIOFileTransformViewLut broken (+ some lut ideas)

PostPosted: Sat Sep 12, 2015 6:43 pm
by Stefan Ihringer
Yeah, consolidating and rethinking the LUT workflow would be good. But I don't know if that's possible without losing features that somebody might use.

So what does Fusion support...

  • built-in LUTs
  • Fuses (ViewShaders)
  • arbitrary .settings files (even including blurs and transforms)
  • probably C++/Cg plugins I guess?

then it has:

  • capability to chain multiple LUTs to create a LUT chain
  • save LUT chains as part of the VIEWER setup (together with the state of the other viewer settings)

and all of this can be done twice:

  • as a buffer LUT (good: works in 3D/materials, bad: lifts the viewer's canvas and checkerboard color, bad: hard to enable/disable)
  • as a 2D LUT (good: easy access through button, bad: doesn't work in 3D/materials)

List of problem areas:

  • building LUTs or even changing them (in the case of buffer LUTs and chains) requires stumbling through multiple levels of context menus (an easy to use dialog or a "mini flow view" that allows you to create LUT chains would be cool)
  • no gain/gamma sliders for a viewer that are within easy reach (like Houdini/Nuke/AfterEffects)
  • distinction between buffer and 2D LUTs (powerful, but to me it feels like a workaround for the fact that regular LUTs were there first but couldn't be made to work in 3D space?)
  • you can NOT switch between multiple LUT chains easily (except with different viewer presets). This is a problem because even in simple cases like applying ARRI's Alexa LUT in a linear workflow you need to chain viewshaders: a log/lin conversion from linear to logC, then ARRI's 3D cube to rec709.
  • LUTs are saved for each viewer and each viewer's A and B buffer. Useful, but also a pain to update LUT presets or even provide facility-wide presets. (Although Nuke has far less LUT-related features than Fusion, I have no issues with it forcing a TD to create a LUT gizmo and install it for the whole facility with a single line of Python code... after all, LUTs aren't like tool colors where everybody prefers their own style.)

Ideas:

  • Maybe save LUT chains as a special kind of settings file that will subsequently be listed in the LUT flyout menu?
  • build LUTs by using a GUI instead of nested context menus. Could be done by having the LUTs available as special tools that you can chain in Fusion's regular flow view or by something like the right side in this screenshot of the MacOS Automator: http://www.osxexperts.net/styled-2/file ... -step3.jpg
  • LUT chains could also be visible below the viewer so you can enable/disable each item. This would allow you to create cool setups that include everything you might need to finetune and check composites (grain boost, saturation boost, slamming gamma up or down). In this case, easy to reach gain/gamma sliders could be added by users instead of being there by default. I made a mockup back in 2012 :geek:

Re: OCIOFileTransformViewLut broken (+ some lut ideas)

PostPosted: Sat Sep 12, 2015 7:41 pm
by Chad Capeland
Stefan Ihringer wrote:distinction between buffer and 2D LUTs (powerful, but to me it feels like a workaround for the fact that regular LUTs were there first but couldn't be made to work in 3D space?)[/list]


That may have been the case, but the workflow is supposed to be buffer LUT for display correction. Are you on an sRGB monitor, a P3 monitor, a 6 primary projector, etc.? The regular 2D LUT is for image correction. Is the input Rec.2020, but you want to see it Rec.709? Are you working in scene space, but have been given a preliminary LUT by the colorist?

The problem I have though, is that the 2D LUT should be applied when you save an image from the Viewer. Otherwise it's a display correction, which is what the buffer LUT is for.

And I'm not entirely sure what the handoff is. If your buffer LUT is going from sRGB to your monitor calibration, that's fine if your 2D LUT is outputting in sRGB. But what if your 2D LUT is outputting P3? Should the buffer LUT be converting P3 to your monitor calibration? If so, it's not working, as setting the buffer LUT's Gamut View's Source Space to From Image doesn't do anything.

Stefan Ihringer wrote:Ideas:

[list]
[*]Maybe save LUT chains as a special kind of settings file that will subsequently be listed in the LUT flyout menu?
[*]build LUTs by using a GUI instead of nested context menus. Could be done by having the LUTs available as special tools that you can chain in Fusion's regular flow view or by something like the right side in this screenshot of the MacOS Automator: http://www.osxexperts.net/styled-2/file ... -step3.jpg


These can be combined into one workflow. You have a .setting file in the LUT folder. It can be opened in Fusion and re-wired and then resaved. Would be even nicer if it was live, though. LUT Macros come close to this, but they aren't Cg and you don't have access to all the LUT plugins as flow tools. But think about it... How cool would it be to have Cg tools in the flow? I know OpenCL is more flexible, but Cg is easy and fast.