Octane for Unreal.

Octane is a GPU path tracer. Unreal is a real-time engine. They disagree about materials, about how a scene should be described, and about what a frame is allowed to cost. The plugin is the translation layer between them, and most of the work is deciding what each mapping should do when the two models don't line up.

Adeline developed that plugin at Otoy. It was used for games, architectural visualisation and VR, which want different things from it: arch-viz will happily wait for a frame, VR will not.

The plugin baked scenes on demand: lighting, shadow and caustics, using the Octane renderer directly on Unreal surfaces. Adeline extended it into an early form of a GPU lightmass renderer — Unreal didn't have one of its own yet.

Geometry had to be reformed going from Unreal's scene representation to Octane's, and the two scene graphs were kept as separate copies in memory, synchronised so a bake matched what was in the viewport. The worst mismatch by far was scale: Unreal reasonably targeted lower-end hardware budgets at the time, while an architect's scene could easily carry hundreds of millions of polygons.

It was aimed at both architects and game developers, but it never reached release — Otoy's partnership with Unity took Unreal off the table before it shipped. Unreal later built its own path tracing and GPU lightmass independently.