Bakes map are black

Hi everyone.

i sculpted a high detail model in zbrush and want to paint in subtnce painter.(i use subtance painter 2018), i export FBX from zbrush and i import to subtance.

when i want to bake the maps, resualt is the black and empty map. 

i searched in internet and find same problem like this. and solutions like scale.

Thanks if you can help me.

Pic 1:

sculpted model with 3.6 mil total point in zbrus. i decimation it and reduced to 30 k.

Pic 2:

Black maps in subtance