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Fusion bugs when working in DWG RCM?

PostPosted: Tue Aug 02, 2022 10:52 pm
by Frediswack
I'm working in resolve color management with my working timeline being DWG and my output set to Rec709
I'm aware of the manged view lut bug and have changed the output space to bt.709(scene) and the image in fusion matches the color page.
But checking the color inspector,
I'm seeing values outside of the 0-1 range.

This doesn't happen when i turn off resolve color management.
Is there a fix for this?

Re: Fusion bugs when working in DWG RCM?

PostPosted: Sat Aug 13, 2022 9:36 am
by shebbe
It's not a bug. Working in RCM automatically linearizes the material in Fusion. This means that for DWG the working space becomes DWG/Linear. The Fusion viewer LUT is a simple gamut + gamma conversion without any form of display rendering applied. RCM uses DaVinciDRT by default as it's tonemapper creating the preferable colors and highlight rolloff. If you want to see this inside Fusion you'll need to unfortunately setup a custom view transform behind the MediaOut node and use that instead.

(scroll down on the images to see all settings)
CST 1: To revert the linearization and jump back to Intermediate to match the RCM working space
Screenshot 2022-08-13 at 11.23.10.png
Screenshot 2022-08-13 at 11.23.10.png (291.46 KiB) Viewed 543 times

CST 2: To match the output transform chosen in RCM.
Screenshot 2022-08-13 at 11.23.30.png
Screenshot 2022-08-13 at 11.23.30.png (374.18 KiB) Viewed 543 times

You could group these two nodes to clean it up a bit but the catch is that viewing through this means colorpicking and value reading is not in linear anymore. You'll have to turn it off temporarily when you wish to do so.

So regarding your above 1.0 values it's correct because it's linear, which is what you typically want for VFX.

Regarding the 'bug'. This has been an ongoing problem ever since the two software married and there are still no tools to work with it properly. The easy solution is to just at least give the ColorSpaceTransform as an option in the Fusion viewLUT settings or have it work automatically by reading the settings from the Color Managed settings with a dedicated entry called RCM. But who knows if they'll ever come up with something. There are dozens of thread about this issue and no acknowledgements I've ever seen from BMD or statements that they're working on improving this workflow.

It gets even worse for graphics because you don't have control over how Resolve will treat the Fusion comps so if you only use display referred data in terms of colors for things like text or motion graphics, it will still treat it as linear and render through the display transform, making it unusable for adding simple lower thirds etc.

Re: Fusion bugs when working in DWG RCM?

PostPosted: Sat Aug 13, 2022 11:33 am
by shebbe
The stuff I explained above still holds true but I thought a bit more about it and came up with a better way that uses the viewLUT.

I tried creating the same steps within a single LUT but the format doesn't support values above 1.0.
Then I tried creating the full steps by first a 1D LUT to go from Linear to Intermediate but I didn't manage to map the full range into a spi1d file yet.
Then I considered just going to a different log format instead with 1D and then apply a 3D LUT to go from there to the DaVinciDRT output space. This works like a charm it seems.

You'll need to apply two LUTs in your viewer. The first is a default LUT in the VFX IO folder.
- Linear to ARRI LogC.cube
Then right-click in your viewer and go to LUT-> Add New -> pick my LUT.
You can grab my LUT here and place it in the LUT folder of Resolve.

Make sure it's in that order. If it still looks weird make sure the default manage settings that you can't remove are set to No Change by going to the LUT menu and click Edit...
2022-08-13 13_32_36-RightView.A LUT Editor.png
2022-08-13 13_32_36-RightView.A LUT Editor.png (13.41 KiB) Viewed 530 times

Let me know how that works out for you!

Re: Fusion bugs when working in DWG RCM?

PostPosted: Sun Aug 14, 2022 10:01 pm
by shebbe
One more update.
I managed to create a working 3D cube stored 1D shaper for Linear to Intermediate.
This works just like the other VFX IO LUTs in Resolve.

So you can use these LUTs instead of what I previously suggested for a much more sensible workflow.