You need to switch the shader in substance painter to "PBR-metal-rough-translucent" in the shader settings menu: https://docs.substance3d.com/spdoc/shader-settings-29130769.html
yeah looks like amazing stuff to work on! Are the characters going to be purely unlit or is there some interesting pbr style shader going on to make metals reflect etc?
I have experience creating modular sci-fi environments in PBR with Substance Painter and Unity 5. https://www.artstation.com/artist/ken0y Best Regards, K
Great stuff, lovely textures! Really hope that we as artists don't lose this care with diffuse maps now that we are moving towards PBR and automatized methods :)
Also, there's an article on Toolbag site that covers process of manual converting M/R maps to S/G maps. http://www.marmoset.co/toolbag/learn/pbr-conversion
I like the lighting choice you went with, the floor lights really bring out the quality of the flooring and the roughness of the material. I'm assuming you're working with PBR for that.