What this the for technique shadows?
Well that’s pretty cool. Would make a sweet feature for unity (hint hint). But I don’t understand, is this a question on how you would implement this (guessing it is because of the ? mark)? Or showcasing a feature? If the former you could try using shadow casting spheres attached to the armature that are then culled from the camera. Or better yet a super low poly version of you model that casts shadows and is culled out.
Don’t know much about shadows though so I’m just guessing 
Well if they have a paper published you could try and implement it in unity. It’s going to be tough as hell, but it’s probably doable (even if barely).
The closest thing to this that is available for unity out of the box is SSAO (in PRO), but it’s not the same to this.