You kind of can’t.
pivot painter works with precise pixels. And its a completely different thing compared to the trails.
The trails can work well for everything. Have been using it as a vector field over everything for the past 6 months but it has its own caviats with Niagara.
as far as getting the grass to move, you have to encode the x/y pivot point of each vertex inside a texture and use that to pass valid points into it.
or, you could encode it into vertex paint, which is a little easier.
Every vertex needs a pivot point.
you could also “eyeball” the pivot point by saying every vertex has a pivot X distance lower than it self on Z.
but this will create tris close to the floor to bend at a different angle than they should / cause artifacts…
I have been trying to come up with a blender script to encode the pivot points, but even blender and python don’t really offer the kind of access needed to do so.
You’d have to be able to select and loop every island of connected verts and assign the same vertex paint value to all the verts.
unfortunately there is no way to automatically process this apparently.
doing it manually over 1000 verts is a bit insane.