Missing information and question about speedtree video: SpeedTree 8: Mesh Anchors

[arno.bax]

I already found the answer by myself!
it's included in this video: https://www.youtube.com/watch?v=S_-HOFEhsg8

[arno.bax]

I followed this video: https://www.youtube.com/watch?v=y0crJqFDCD8 and i understand nearly everything.
The only point that i am missing completely is also my question.
what is the black icon named twigs in the generation editor and how do you make it and use it. I ask this question because i just can't find the answer to it and it seams to be an important step for the frond behaviour.

Thank you.
Arno Bax