Currently check_for_collisions=True only considers the scattered objects and not their surroundings.
For such cases, I would recommend using Isaac Sim’s API to spawn/move objects and check for their collisions/overlaps with their surroundings as well.
Example of physx api call for checking for overlaps:
def on_overlap_callback(self, hit):
print(hit.rigid_body)
single_hit_check = False # iterate all overlaping objects
get_physx_scene_query_interface().overlap_box(extent, origin, quat, on_overlap_callback, single_hit_check)