Just spent the last few hours learning how to generate materials and publish them to UE4 with Substance Designer. By setting up the materials in Designer correctly, you can get a lot of variety. Here is my first go at it:
Pipe Valve Material from within UE4
Only problem is that the procedural aspects of the material (paint chips, dirt, etc) seem to be tied to the normal, AO, and curvature maps used when published within Designer. If I attempt to change them inside of UE4, it breaks the procedural generation (it still works, but the generation effects do not follow the mesh curvature or AO). I would like to be able to use the materials for any object by swapping out the normal and AO maps, but cannot seem to get it to work. Are there any Substance Designer users in here who can help?