bvhtree just got a radius/point check to detect face intersections

Game Engine Game Engine Support and Discussion
1

With the new command in mathutils
Bvhtree sphere test, you can grab /circle select in the game engine and the viewport, on objects that have no collision bound, you can use it to operate on large meshes without iterating over all the vertex or faces,

(first you must build and balance the tree though*)

So dynamIc texture painting can wrap across seams and also many new possibilities with mesh editing using bpy and a network socket.

You could also do a form of LOD like my kdtree LOD, but more accurate as the shape of the face representing the object can have size and dimensions unlike a point.

Useful functionality to have, something we already supported for KD-Trees:

Committed BVHTree.find_nearest_range(), 0, see API doc 1 and
example script 2.

2

https://www.blender.org/api/blender_python_api_2_77_0/mathutils.bvhtree.html#mathutils.bvhtree.BVHTree.find_nearest_range