Blender Applink 2.8
Blender Applink comes inside of Blender 2.8. Please download the latest blender 2.8 from here: https://builder.blender.org/download/
Enable Addon in blender:
Go to Edit -> User Preferences.. Click addons tab.
Search '3D-Coat Applink' and press checkbox to activate it.
Blender -> 3D-Coat -> Blender workflow
Select objects you want to take into 3d-coat.
On right side of 3D View there is '3D-Coat Applink' panel.
Press Transfer and go to 3D-Coat. (You can also find these options when you press 'SHIFT + Q' key in 3D view.)
Turn on 'Treat material as separate textures'. After you are okey with other settings press 'Ok' button
After you are done with painting go to File -> Open in Original App.
Select what texture you want to export. When you done your other settings press Ok.
Go back to Blender and press 'Update' Button.
3D-Coat -> Blender workflow
When you are paint your painting go File -> Export to -> Blender
Name your file and select type to .FBX and press 'Save' button
You might have to play with 'Apply scale' setting to find the right scale for you. I have used 0.03.
Select which textures you want to export. Applink automaticly updates your: color, roughness, metalness and normal maps.
Press ok when ready and go to Blender and press update. (You can also find these options when you press 'SHIFT + Q' key in 3D view.)
TUTORIAL VIDEO 1 (Blender -> 3D-Coat -> Blender workflow)
TUTORIAL VIDEO 2 (3D-Coat -> Blender workflow)