how to get terrain verticals to auto paint?

[FrenzyTheory]

https://www.youtube.com/watch?v=MlgvfEicdwU

how did this user get his verts to auto texture when he
was modifying the terrain.

[jonimake]

https://www.youtube.com/watch?v=MlgvfEicdwU

how did this user get his verts to auto texture when he
was modifying the terrain.

You need to setup the terrain material so that it blends based on the terrain surface normal angle.

[fighter5347]

Take a look at the vehicle demo -> I think they used such a material