05.02.2024 – CG process

Week 15 – CG Process: From Matchmove to Final Composite

Throughout the previous classes, delved into various stages of the CG production pipeline, including matchmove, clean-up, and color grading. Now, it’s time to integrate these processes to seamlessly composite CG elements into a video.

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Key Processes:

• Matchmove:
  • Undistort the original plate and analyze the scene using the CameraTracker node.
  • Create cards to match on the trackers. For a detailed guide on matchmove, refer to my previous post: Matchmove.
• Clean-up:
  • Remove specific objects or markers on the original plate using projection techniques.
  • To lighten the script, render and reimport the cleaned-up plate (preferably in .exr format to avoid quality loss).
  • Roto the plate if necessary. For more details on projection, check my previous post: Projection.
  • Slap Comp:
    • Before starting the compositing process, create a simple slap comp by merging CG on the cleaned-up plate. This aids in checking the before and after of your work.
• Compositing:
  • Utilize render passes from 3D tools to composite CG onto the plate. For insights into AOVs and passes, as well as adjusting multipass and relighting, refer to my previous posts: AOVs and Passes and Adjusting Multipass and Relighting.

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Additional Points for Natural Compositing:

• Match Color using a Grade Node:
  • Whitepoint from the original source to neutralize white.
  • Gain from BG source and Blackpoint from the original source to neutralize black.
  • Lift from BG source.
• HueCorrect Node:
  • Select color (Ctrl), adjust the curve, and add points on the curve (Ctrl+Alt).
• Toe Node:
  • Select the shadow area from the BG plate to match black. For more options, use the BlacksMatch gizmo.
• MotionBlur3D:
  • Create a motion channel using the camera.
  • Apply the VectorBlur node with the motion channel. If possible, use motion vector channels rendered from 3D programs for more accuracy.

Finishing Touches and Quality Check (QC):

• Incorporate Aberration (Gizmo), Defocus, LightWrap, Grain nodes, etc.
• After composing everything, conduct a quality check (QC). Merge the original and final plate with the Difference operation.

• Utilize QCTechnical (Gizmo), SliceTool (Gizmo), and Colorspace nodes for thorough QC.