How to limit decals ''bleeding'' on perpendicular surfaces

[RyanB]

This is how you can mask out any normals that were up or down. To mask out anything perpendicular to the projection angle requires creating a blueprint container for your decal and creating a Material Instance Dynamic and setting the decals X rotation to be the value of a VectorParameter. Then in the material, just plug in that new vector value to one of the pins on the dot product.