I have a question [Landscape]

Why when I place a floor some pixels above my landscape there are some diagonal lines that appear on the surface. Thoose lines look like shadows at least thats what I think and they are parallel to each other. Please tell me what are they and how to remove them. I’m new to the engine but I know some basic things about it.

Can you post a screenshot?

Hard to say without a screenshot. If your light isn’t set to movable perhaps it’ll go away if you rebuild the light?