Options for overhang detection during procedural object spawning

I'm trying to make a tool for procedurally generating objects on my terrain.

Generally spawning works fairly well, but I'm trying to figure out how objects that spawn on edges of cliffs and sharp edges can be detected and avoided. Objects that overhang basically.

Right now I already use a raycast to check for a position to spawn the objects. The only way I can think to do some sort of overhang detection would be to cast 4 more downward rays from each corners of the object, creating a plane. If that plane intersects the terrain than its not flat.

But this is just checking if the square underneath the object is uninterrupted, not necessarily only overhanging objects as a bump under the object would cause it to fail. Plus 4 more raycasts is quite an expensive road that i'd like to avoid. If anyone's got some suggestions for a better idea I'd love to hear it.

 

https://docs.unity3d.com/ScriptReference/TerrainData.GetHeights.html

Probably want to look at terrain smoothing as well.

 

What if the terrain is not using Unitys terrain. I made a custom Blender planet that i am spawning my objects on.

 

I'm not sure exactly, but a quick Google search found this:

https://forum.unity.com/threads/solved-mesh-vertex-position-in-world-space.30108/

 

okay that helps a bit with meshSpawning, but i'm working with raycastSpawning. And also how is that relevant to overhang detection?

 

If you know where the mesh is in world space, you should be able to tell if the object on it is "too high," in other words if it overhangs.

Another quick search:
https://forum.unity.com/threads/cal...form-positions-across-a-meshs-surface.640747/

 

Does your scene have a navmesh? I Find the closest point to my spawn location that’s on the nav mesh.