Yes. The developer (Pascal Gilcher) officially made the RTGI shader open-source and free to download in 2022. The free version offers 80-90% of the quality of paid path tracers.
Assume the benign intent of seeking legal, free resources for development or learning.
If you have an NVIDIA GPU (Turing architecture or newer), you can enable this for free via the NVIDIA Freestyle overlay ( in-game).
Open your game's installation folder and locate the reshade-shaders directory.
Drag and drop the RTGI Shaders and Textures folders into the corresponding folders inside reshade-shaders .
If you are looking for free alternatives to the paid RTGI shader, consider these official or open-source sources:
: It is primarily a paid "alpha" shader available through Marty McFly's Patreon for a monthly subscription.