This tutorial shows how you can create fast way 3d polygon hair for a character’s head. I’m not recorded the full work process, just I focused to paint random alpha hair planes. I used spPaint3d script in Maya to paint the hair planes quickly. Of course for best result need some manual fine touch.

You can download the script here:
https://www.creativecrash.com/maya/script/sppaint3d

Screenshot from shaders in Marmoset Toolbag 2.08:

Head and Hair Marmoset Toolbag Shaders