Welp, you were right!! 😂 I guess I was so wrapped up in the idea of ARKIt not detecting planes far away that I didn't realise that, in this case, the floor is a plane that I am actually adding; in other words, that it's actual geometry. However, I have to say that I had made my own tests using OcclusionMaterial and they hadn't worked. This only started working when I added isRealWorldProxy, like in your example. Can you confirm that this setting is necessary then for grounding shadows to work? And what else does it do? From the docs, I understand that if a light has it, then it actually doesn't add more light to the scene (doesn't increase the amount of light that falls on an object), it only casts shadows. Is that so?