Modifying the show grading space using roles

grading-space-roles-base.ocio (with thanks to Kevin Wheatley!)

ocio_profile_version: 2.1

search_path:
  "grades/$SCENE/$SHOT/$ELEMENT:
  grades/$SCENE/$SHOT:
  grades/$SCENE:
  grades:
  luts:
  /my/global/config/location/luts/no-op"

roles:
  show_turnover: Input - RED - Linear - REDWideGamutRGB
  show_grading: Input - RED - REDLog3G10 - REDWideGamutRGB
  show_delivery: Input - RED - Linear - REDWideGamutRGB

environment:
  SCENE: ""
  SHOT: ""
  ELEMENT: ""

displays:
  Rec709:
    - !<View> {name: Show Look, colorspace: showLook}
    - !<View> {name: Show Look Graded, colorspace: showLookGraded}

colourspaces:

  - !<ColorSpace>
    name: showLook
    family: "Output"
    equalitygroup: ""
    bitdepth: 16ui
    description: |
      Simulation of show look output (contextual)
    isdata: false
    allocation: uniform
    allocationvars: [0.0, 1.0]
    from_reference: !<GroupTransform>
      children:
        - !<ColorSpaceTransform> {src: ACES - ACES2065-1, dst: show_grading}
        - !<FileTransform> {src: show_lut.cube, interpolation: tetrahedral}

  - !<ColorSpace>
    name: showLookGraded
    family: "Output"
    equalitygroup: ""
    bitdepth: 16ui
    description: |
      Simulation of show graded output (contextual)
    isdata: false
    allocation: uniform
    allocationvars: [0.0, 1.0]
    from_reference: !<GroupTransform>
      children:
        - !<ColorSpaceTransform> {src: ACES - ACES2065-1, dst: show_grading}
        - !<FileTransform> {src: primary.cdl, direction: forward}
        - !<FileTransform> {src: show_lut.cube, interpolation: tetrahedral}

grading-space-roles-input.ocio

ocio_profile_version: 2.1

roles:
  show_turnover: Linear ARRI Wide Gamut 3
  show_grading: ARRI LogC3 (EI800)
  show_delivery: Linear ARRI Wide Gamut 3

Diff of base and merged configs:

% diff grading-space-roles-base.ocio grading-space-roles-merged.ocio
12,14c12,14
<   show_turnover: Input - RED - Linear - REDWideGamutRGB
<   show_grading: Input - RED - REDLog3G10 - REDWideGamutRGB
<   show_delivery: Input - RED - Linear - REDWideGamutRGB
---
>   show_turnover: Linear ARRI Wide Gamut 3
>   show_grading: ARRI LogC3 (EI800)
>   show_delivery: Linear ARRI Wide Gamut 3