It's a question I've been thinking about for some time... How do you effiently find a path on a 2D tile-based multilevel map? The map I use, for example, is 2048 on 2048 tiles wide. It has 14 levels and levels are connected by stairs, ladders, rope holes, ...
How would you introduce level-changing tiles into A* in an efficient way? I know it is possible to add multilevel path-finding by just adding edges from an up-node to the corresponding down-node. But then path-finding isn't very efficient.
For example. What if the current node (e.g. [100, 100, 7]) is directly under the goal (i.e. [100, 100, 8]), and we can't go up anywhere near the current node. Instead we first have to go down some levels, and then up again, only then to reach the goal. A lot non-existing paths will be considered (= a lot of time and computation) before we finally find an existing path.
Feedback appreciated, Gillis