At this point in time i have noticed that allot of Blender’s baking options seem to be targeted towards internal refinement rather than external use.
- Baking Diffuse colour currently adds in lighting variations.
- There is no option currently for baking out a metalness map
- Roughness map’s requires very specific settings and post processing to act correctly in other software (Generally inverted for use in UE4)
- Specularity maps needs very creative re-wiring of nodes to bake.
blender needs a PBR Bake option that then lets you bake out a
- Albedo map (flat colour map)
- Roughness / Gloss (That doesnt bake your HDRI on to the material)
Another option that may work is adding in a “Flat Bake” option to the Bake panel, This could give a flat even outcome that ignores lighting & other objects within the scene.