That was just the wind xgen modifier + colliders. But the right way to get a believable simulation is dynamic nhair curves for the guides (or animguide modifier) and xgen colliders for the single fibers.
Thank you Justo! I'm using guides. I'm on Maya 2015 and groomable splines definitely are not suitable for long hair, whereas interactive grooming is not present at all in the old xgen plugin. I'm impatient to try this new feature.
A project I made to improve my character skills. It's a semi-realistic take on Young Nahoko from "The wind rises". Modeling done in zbrush/maya, texturing in Mari, shading, lighting and rendering with Arnold. Xgen hair. On my Artstation too: https://www.artstation.com/artwork/5484z