Approximate, incremental nearest-neighbour algorithm for moving bodies

Question

Bounty

This question raises several issues. The bounty will go to an answer which addresses them holistically.

---

Here\'s a problem I\'ve been playing with.

Answer 1

Have you tried using a quad tree?

That is, recursively partition the "world" into a graph with four subnodes each. The tree can then quickly check which objects are inside a particular square of the world and discard the rest. A very effective culling technique often used for improving performance of collision detection in games.

If this is 3D, extend it to an octree.