Hi everyone !
I have searched on the forum and all over the internet for this problem but i can’t find any solution. 
So i came to you hoping you would know.
So i created a mesh on 3ds max, did some sculpting on zbrush, made uv of the modified basemesh on 3ds max. And when I try to export a map with the Render Surface Map, i’ve got weird faceted maps (as you can see on attached files).
Same happens on zbrush when i try to create a displacement maps or a normal map.
I did some rough uv’s on the first model in 3ds max and the same thing is happening. So i guess the problem comes from the basemesh itself.
But can’t find the solution, i tried some reset xform, some unify normals… None seems to work. I’m kinda desperate now 
So if you can help me, i’ll be really glad. Thanks for your time !