   Pathfinding on a 3D heightmap
  ello guysi just need to ask on how to implement A* pathfinding on a heightmap implemented using a quadtree and a heightmap from an bmp file.I already implemented A* on 2D tile map since i can divide my map to a tile.i just dont knw how to implement this on a 3D heightmap since the map are not implemented using tiles.   
  Even though it is rendered as a 3d object, it is still a 2d surface (most likely, unless you have some caves or otherwise undercut geometry), and each point on that surface can have attributes such as a gradient, material, and flags. So it should be straight forward to adapt your tile based A* algorithm to this 2d grid.   ;  also you can create 3d array with all the nodes(if map not big), Or do search in 2d array. It's pretty simple. I yesterday write my A* algo + binary heaps and he is praty fast 500x500 map he found path by 10 ms.;  Create a 2d tileset that describes the difficulty of travelling from one location to another.If there difference in height is positive (uphill) then have a higher difficulty based on the gradient.If there is no difference then have the difficulty as 0If there is a downwards slope then have a difficulty < 0 unless it becomes too steep and then make it positive.That way the computer can plot a path that takes in to account the height and possible paths across the terrain.   