Noodles: A Path Tracer Made of Blender Nodes
Noodles is a small physically based ray tracer implemented fully inside Blender's rendering engine. Specifically, it is implemented purely as a network of (many!) nodes assembled in the shader editor, see the illustration above.
Many rendering systems, including Blender, allow users to create and edit their own materials based on powerful node-based shader editors. For instance by combining multiple BRDFs using various "add" and "blend" nodes, or by creating procedural textures out of mathematical functions. As shown in this project, they are indeed flexible enough to implement a full raytracer inside a custom material.
Some basic "rules" apply: all nodes available in Blender's shader editor are fair to use, except for the Script Node which allows you to write arbitrary OSL code inside of it. This would defeat the main point of this project and take all the fun out of it. For similar reasons, no add-ons or custom Python scripting should be abused to generalize or circumvent the node system.
The main rendering loop uses path tracing (including multiple importance sampling between BRDF and light sampling) to compute global illumination.
