Beginner in Graphics - On a Quest to do the foliage from the Witness

Hi,

You (hardcorebadger, AcidArrow) combined two features:
One is to fade out away the face when almost perpedicular to the camera view.

The other is to use a normal vector which roughly point away from the center of model.

So we need two normals per vertex.

I want to combine these features in my tree. My idea is to simply interpret the local position of each vertex as its second normal! The origin of the fluffy tree mesh top will be somewhere inside the trunk, it think on the ground. I tried it in Unlit and Surface Shader, but it did not work.

Can somebody help?

Kind Regards,
Chris