I'll be covering here in writing what the great William Faucher has created a video on regarding the ACES workflow from Unreal 5/4 to Davinci Resolve.
General Information
Linear SRGB is the default colour space in Unreal Engine. Any conversion either go to Linear sRGB or from Linear sRGB
Once the OCIO config file is setup you wont have to redo this during the project as you can reuse this file
Unreal is in linear sRGB, the viewport has an ACES filmic tonemapper applied, giving us the substantial benefits of the ACES tone curve, filmic highlight rolloffs, etc.
However, the ACES colorspace for post-production work is intended to be linear. What we get out of UnrealEngine with default render settings isn't in linear, the tonemapper remaps those linear values to the 0-1 range. The OCIO config disables that tonemapper at render time. Which is why we jump through all the hoops in this to render in linear.
DJV is a great viewer that lets you view EXR sequences quickly without compositing them together. It also has lots of features within it to preview such as LUT application.
Links
ACES Configs: https://github.com/colour-science/Ope...
ACES 1.2 Config: https://github.com/colour-science/OpenColorIO-Configs/releases/tag/v1.2
Davinci Resolve: https://www.blackmagicdesign.com/products/davinciresolve/
Step 1 - Setup OCIO Config File In Unreal Engine
Download link 2, ACES 1.2 Config zip file. Then extract this file wherever you desire
Open your Unreal project and create a folder called OCIO Configs
Right click in this folder and create Miscellaneous>Open Color IO Configuration. Name this OCIO_Config_01
Double click this config file. Once open click the three dots next to the 'Configuration file' input and select the 'config.ocio' file from the ACES 1.2 folder you extracted earlier
Under the 'Color Space' > 'Desired Color Spaces' click the + button twice to add two elements
Set index [0] to 'Utility - Linear - sRGB'
Set index [1] to 'ACES - ACEScg'
The editor may lag clicking this drop down but be patient
Step 2 - Render Settings in Unreal Engine
When rendering you should use the Movie Render Que to get better quality renders (Enable this in plugins)
Add your sequence to the movie render que. Click 'Unsaved Config' Under Settings to set up the properties
Firstly, delete jpeg sequence, click the green setting button and add, '.exr sequence', 'Anti-aliasing' & 'Color Output'
For reduced file size you can use the compression method 'DWAA' in exr sequence settings
Set Anti-aliasing temporal sample count to 16, tick 'Override Anti Aliasing', tick Render Warm Up Frames
Open Color Output Tab, tick 'is Enabled', Load config file you created 'OCIO_Config_01'
Set the Source Color Space to 'Utility - Linear - sRGB', set the Destination Color Space to 'ACES - ACEScg'
In the Output Tab, file name format, before the name add the prefix 'ACEScg_' so that when editing you know the colour space clearly. Remember to also set your path to where you want the frames to render to
Finally click the 'Load/Save Preset' button and save this config as a preset in your project so if the render fails or you want to change cameras you won't have to reconfigure this.
Once you press Render Local, all your frames should be produced into your Local folder selected earlier
Step 3 - Davinci Resolve Settings
First thing to do before you import anything is to setup the project settings as this cannot be changed later. Under 'Master Settings' set your resolution, timeline frame rate and playback frame rate (30 for my project), video format and bit-depth (10-bit)
Under the 'Color Management' tab set: Color Science: ACEScct ACES Version: ACES 1.2 ACES Output Transform: Rec.709
This is all thats required. Though I would suggest that you click the three dots in the top right of the window and 'Set current settings as default preset'. Just remember to change your FPS per project
Now we just need to import our frame sequence. The easiest way I've found is to go to the media tab and just drop the actual windows folder into the large section under 'Media Storage'. You should now see the frames as an individual frame sequence.
It is important that you right click this sequence and click 'clip attributes' and set the correct Video Frame Rate here too!
Right click your clip, go to 'ACES Input Transform'>Color Space Conversion>ACEScg - CSC
Now go to the edit tab and just drop this frame sequence into the timeline and it will create a timeline for you. Now you are ready to edit!!