Bake impossible

Hi o/

I try to bake a .OBJ sculpt on a .FBX low poly before start the textures and i tried all i know but impossible to succes the bake. 

My sculpt is rlly high poly so i separate it in several parts, and do exactly the same on my low poly.

Each time i try to bake a part, substance take its time, it's ok but it give me empty map or map with nothing on it.

Here : thickness, diffuse (it's ok here i didnt put color for now), curvature and normal maps

I checked all files, and all high poly and in correct position on the low poly.
I tried to import again both high and low poly files, to reduce resulution, to reduce weight of file by separate again some parts.

I had some error some time like "mesh normals are invalid", "unexpected illumination model" or the last one this morning : "no object detected to attach a new mesh instance". Some time Substance tell me that the bake failed but even when it didnt failed, i'd the same problem of empty maps.

I tried to bake a differents old work of mine with exactly the same method for see if it's work and it's work well.

I rlly dont understand where the problem comes from and how fix it.