A* pathfinding in 3D

Question

I've looked through some A* pathfinding algorithm examples, but as far as i know they work with grids e.q -> http://qiao.github.io/PathFinding.js/visual/

But how can I use this algorithm in my 3D Engine(I'm using Unreal Engine 4)?

Answer 1

Actually A* does not use dimensions.

A* works with nodes and each nodes have paths to other nodes.

In the case of a 2D grid every cell is a node and every boundary is an implicit path (left, right, up, down, and/or diagonals), the key here is that it is implicit.

This is a trick to reduce the memory footprint, but A* itself does not require a 2D or 3D grid. You can use A* with explicit paths/connections between the nodes such as a country road map.

In the case of a 3D grid, you apply the same method as a 2D grid but now you can move in the 3rd dimension as well.

But this is not how most 3D games use A* because the memory needed for a usable 3D grid becomes too large very quickly. Instead they use navmeshes.

Search the web for "navmesh"

• http://en.wikipedia.org/wiki/Navigation_mesh

Blue part is the navmesh:

A* works on those: each triangle is a node, each edge is a path.

There isn't an up-down-left-right, there are neighboring triangles through edges A-B-C.