ImGui node graph editor over rigNodeComponent CNodeGraph.
Complete built-in catalog: Values, Maths, Modulators, Logic, Vectors, Color, Output - search in Add node, typed pins (green/blue/pink), color picker, live eval, Open/Save .rig. Ctrl-P opens a Patch bay (From / Destination rows) over the same graph.
Hero seeds a color-wash graph (LFO to Map to Brightness) that tints a scene circle via Color Ref.
Artist guide: docs/nodes.md (cheatsheet, catalog, recipes).