Decal that does not draw on sides of an object

Hi,

I’m trying to build on the Decal Graph and create a decal that does not draw on the sides of a cube so that the decal in practice “ignores” drawing on anything but the ground. I’ve found out that you can use the DDY Node | Shader Graph | 7.1.8 operator but I seem to be using it wrong.

I hope someone could point me in the right direction, thanks for you time :slight_smile:

Bump!