So I've been following along with this tutorial for making a grass shader, for reference I am relatively new to the shader world: https://roystan.net/articles/grass-shader.html. I've pretty much gotten everything to work and I am starting to work on modifications, so it fits better with my project. The basic idea behind what I want, is I have a geodesic dome as my planet surface and I need grass to grow on the meshes surface. Grass should grow on any of the hexagons that face away from the origin, but not on the side of the raised hexagon platforms. In it's current state the grass grows on all faces of the mesh. I've tried limiting when blades can spawn by checking that their normals are above a certain value in the geo function. So far it only limits spawning in certain regions. I'm pretty certain, I'm correct in my understanding of using normals to limit the grass. I just don't know how I should go about achieving it. I'm pretty lost on where to go from here, and would love any help. Thanks!