Documentations of graphics software are all super interesting.
  • Arnold
    • Arnold renderer by Solid Angle.
  • VRay
    • VRay renderer by Chaos Group.
  • Maxwell V3
    • Maxwell renderer (V3) by Next Limit.
  • Maxwell V4
    • Maxwell renderer (V4) by Next Limit.
  • RenderMan 22
    • Pixar’s RenderMan.
  • Corona
    • An interactive documentation for 3ds Max.
  • Redshift
    • Redshift renderer.
  • Unreal Engine 4 - Release Notes
    • Release notes of UE4, each version is worth a read if you are a fan of rendering technologies (real-time).
  • filament
    • Compact and feature-rich real-time renderer with extremely nice documentation.

Entries listed with no specific order.