We take a look at the Volumetric Sampler in UE5 PCG (Unreal Engine 5 Procedural Content Generation) to be able to volume sample any environment and filter out the ground / floor, the walls, and the roof / ceiling to spawn whatever we want without needing to sample individual meshes with a mesh sampler.
https://dev.epicgames.com/community/learning/tutorials/dLOM6/unreal-engine-volumetric-sampling-in-pcg-is-a-lot-more-powerful-than-you-think