Dots on face during 3d Face scanning? Why? (pictures)

Jonathan85

I came across this:
http://3.bp.blogspot.com/-TYtSdyZ0v-Y/Vp_v06xG58I/AAAAAAAAG70/NUz-4_laAC4/s1600/marekNovotny_Texture.jpg
http://4.bp.blogspot.com/-vZffYyEYflQ/Vp_EFtkF8EI/AAAAAAAAG60/Lz95wBZwqqk/s1600/20160120_112859.jpg
https://pbs.twimg.com/media/CZLknKLW0AAaetZ.jpg:large

Its some game dev company scanning real human faces for use in their project (game) using some DSLR cameras (photogrammetry scanning). They are not scanning only their neutral face expresion but also additional face expresions (anger, sad etc.) probably for facial animation.

My question is simple, what are the black dots marked on the characters faces? I dont believe its for the scanning itself (since i have some experience with photogrammetry and know that they are not needed for the scan itself). I believe its for additional "manual" processing in additional program and its used for facial animation in later stages of development. I believe that 3D animators place later "markerss" ("numbers") on each of these spots and it will help to pair each of the face expresions with the neutral face speeding thus the process of creating the facial animation.
 
Am i right? How (in which programs) are the dots used and what for CONCRETELY? Thanks a lot

Hito

yea you're right. they're mocap markers for capturing expressions

Jonathan85

but how do they work exactly, in which program and how do they help?Because the base for the head will be the neutral face expresion which they will retopologize (and model the rest/back of the head) and then they will merge in gradually the rest of the (hipoly) expresions and they will "sculpt" or somehow try to merge them with the retopologized (subdivided) neutral face...
Is that correct? How exactly and in which part of the pipeline do those markers help please...?

Bal

From my experience those marks are just there to show where to place the reflective markers for motion-capture.
It's faster to draw marks on the actors face like this (often times using a mask with holes), so that whenever one of the markers falls off it's quick to put one back in the right place.
As for software, well that's just whatever mocap solution is being used.
The fact that the actor has these during the 3D Scan process is often times due to the fact that they are scanned on the same day as they do mocap (cheaper), and the photos can then be used to double-check later on that the actors real expressions match with what the mocap has recorded.