@Omar Vector this is not correct. What you show in that screenshot is attempting to retrieve a material using the hit result face index. These are totally different things . Face index will be a value in the hundreds or thousands, corresponding to a single index from the array of ALL faces on the mesh that was hit. GetMaterial() returns a value from the Materials array which is going to be a handful of indices corresponding to the material IDs of that mesh.
Using one to retrieve the other is almost guaranteed to be out of bounds.
It won’t crash, cuz it’s blueprint. But it also won’t work 