Terrain Detail Mesh - Get World Position and Rotation

Hello everyone,

I currently search a solution to retrieve exact world position and rotation of each Detail Mesh on terrain. I search a lot and it's seems there no way to do that. I work on trash terrain cf screenshot. The terrain tool have a good performance but i can't use it because i don't find a way to retrieve postion of each Detail Mesh painted.

If there is no solution can you give me a way of what i have to learn to recreate a shader "Detail Mesh". A way to display a lots of objects on a plane with good performance. I'm new in shader so it's hard to find a way to do that.

Thanks a lot for your answers