Eyesight
Eyesight is the 3D renderer integrated into BrickLink Studio for creating photorealistic images.
(Another renderer integrated in that tool is POV-Ray.)
Eyesight is a command-line tool spawned by Studio when you are triggering a rendering from its user interface. It can be run standalone manually if you specify the correct options.
To see a list of all available options, invoke it from the command line with this parameter:
eyesight.exe --help
Note that that executable can be found in a subfolder e.g. PhotoRealisticRenderer\win\64.
What is Eyesight?
You can learn from the COPYING.txt file delivered with BrickLink Studio that
Eyesight is based on the open source "Cycles" renderer
The version integrated in BrickLink Studio 2.24.2_4 is Cycles 1.9.0.
It has been adapted for BrickLink Studio by KOG Corporation.
Cycles is a renderer which is part of Blender. Its source code can be found at