How to make decal material that "projects" on a surface ?

I’d like to have a surface (extruded plane) with material that projects onto another surface beneath it (could be a wall, ceiling, floor, terrain, etc.)

Imagine a terrain mesh with terrain material, and a decal mesh with foot steps (or oil spill puddle) material (colored texture) placed slightly above the terrain mesh. The decal texture needs to be projected to the terrain mesh to conform to it (and perhaps when terrain texture is baked, the decal should stay on the baked terrain texture).

Is it achievable with Cycles ?

How do I set up this contraption ?

Thanks

need to subdivide and use skrinkwrap or retopo!

happy bl

Is that what I described? :no:

I am aware of srinkwrap. I need to literally project texture, without conforming any geometry itself.

EDIT: I am guessing something like this is what I need (but I haven’t watched it yet, so I might be wrong):

you said you wanted it to conform

" The decal texture needs to be projected to the terrain mesh to conform to it "

if not that then show some pics so we can better see what you mean !

happy bl

I don’t see the need to have any extra mesh. You can do all that in the terrain’s material…
And there are quite few ways to do it also… you can do it with custom uvmaps, the mapping node, by using others objects coordinates, etc…
And then, play with masks, rgbmixes and shadermixes.