Port blender 2.8: add-on + export
The add-on is now available in blender 2.8 (must still be loaded with the script mechanism).
The export to MRF file format is functional with a temporary hack: principled BRDF is export as colored lambert. Should be done correctly when MRF supports this type of material.
Using MRF for rendering directly in blender 2.8 has yet to be validated.