All objects that are the same colour share a single material. If I join all these separate objects into one, the materials all transfer and I retain the correct colours, however I now want to modify these materials in order to add different normal/roughness etc. maps.
I cannot add these maps individually to each coloured material as there are potentially hundreds of different materials. So I need a method of merging all the colour data into one material which I can then change the other aspects of without the individual vertices losing their colour information.
The model was originally exported from UCSF Chimera. I can use either Blender 2.79 or 2.8. I would prefer to have the whole model as one object but would be ok with it remaining as separate objects. Colours must remain exactly the same and in the exact same place (very important, no manual recolouring).