As other particle buffs will know, one of the types of particles you can spawn is a spaceObject particle. Essentially you specify a P3D file and a particle is made using that model. No geometry other than visual is spawned.
It's possible to balance the drop parameters to spawn immovable objects, but there's no control over the orientation. I suspect a similar method is used for island clutter, the small vegetation objects and rocks that you see spawning and disappearing depending on your location & movement. Those objects also have no geometry other than visual, i.e. no collision, shadow or viewblock geometry etc.
Does anyone have a clue if that clutter spawning method can be accessed for more flexible use? I'm thinking about things like spawning random object clutter around a player, not as part of the island config, which is not particle based and so can be spawned and culled at will.