There is what you said. I read it. Even read it again. So I ask…why are you talking about allocated memory and invalid pointers? You are talking about things related to memory management.
Yes, I know unreal supports more than real-time conventional rasterization.
You do need someway to talk about various objects if you are doing ray-tracing and/or physically based rendering so that you can compute more accurate colors. But, you don’t need to ‘render’ everything.
You don’t even have to ‘render’ anything. You can use Signed distance functions: