The idea of baking is ancient. I recall people used Lightwave and Brazil render for 3d max in late 90th or something . Long before Render-to texture dialogs appeared in 3dmax . It followed an idea of "baking camera" using surface normals and UV space for ray tracing. Or just baking shader into UV including reflections.
Alias Maya and Kinetex 3Ds Max as they were before Autodesk, offered built-in baking. Its still there now Render to Texture afaik its called where you can choose types of maps you want to bake including lighting. Unreal Tournament baked lighting info on the base texture to have that distint look. Below is an example,…