Enlighten
Real-time indirect lighting middleware that let bounced light change as the sun set or a wall collapsed — without rebaking the lightmaps.
Baked lightmaps look good but are frozen: move a lamp and nothing adds up any more. Geomerics in Cambridge tackled this with a radiosity variant that does the heavy lifting in advance on a simplified version of the level, leaving only the actual light transfer to be computed at runtime. The result was cheap enough for consoles.
Frostbite used Enlighten from Battlefield 3 onwards, and Unity 5 built it in as its real-time GI in 2015. ARM bought Geomerics in 2013 and sold the business on in 2017. Hardware ray tracing has since taken over much of the same job, with far steeper demands on the graphics card.