ignore depth buffer for terrain

Hello.
Is it possible to make one material render always over terrain (but below detail meshes and grass!).
I want to achieve a situation where that green grid would never be cut away by terrain mesh, but still render below terrain grass, detail meshes and other objects.
So it has to do something with depth buffer? Like set the grid material to ignore terrain textures’ depth? but how…?

Thanks in advance!

3090-bufferquestion.jpg

solution 1

use projector for terrain-only layer

solution 2

paint grid on terrain as any other texture. this can be done also procedurally by scripting

solution 3

reproduce geometry of terrain to plain with grid

solution 4

improve shaders to draw grid between terrain and terrain details with ignoring z-buffer