Updating single nodes to expand pathing in Grid Graph(2D) suddenly skips a node


I’m creating a top-down 2D game where you can mark tiles(nodes) to dig your way out. I’m currently using this code to make it possible for the AI to walk once a tile has been dug:

   AstarPath.active.AddWorkItem(new AstarWorkItem(ctx => {
            var makeWalkableNode = AstarPath.active.GetNearest(cellPosition).node;
            makeWalkableNode.Walkable = true;
            var gg = AstarPath.active.data.gridGraph;
            gg.GetNodes(node => gg.CalculateConnections((GridNodeBase)node));

However, when they reach a certain distance from the center of the grid it skips a node.

The console prints the “makeWalkableNode” position once it has been dug, which you can see skips a step for some reason. Scanning the whole graph with AstarPath.active.Scan(); “fixes” this problem since the uncolored area connects, but is not good for performance.

If I change the Grid Graph’s width and height this “node skip” happens earlier. Doesn’t matter which way I dig, the skip forms a grid pattern.

I’ve tried reading the scripts and documentation to find if a single Grid Graph is divided into subgraphs with 1 node’s border, but wasn’t successful.



Might it be that your cells don’t line up with the centers of the nodes? Could you show a screenshot of this?


The cellPosition is a Vector3Int which is the bottom-left corner of a cell. I tried this:

 AstarPath.active.AddWorkItem(new AstarWorkItem(ctx => {
            Vector3 test = cellPosition + new Vector3(0.5f, 0.5f, 0);
            var node1 = AstarPath.active.GetNearest(test).node;
            node1.Walkable = true;
            var gg = AstarPath.active.data.gridGraph;
            gg.GetNodes(node => gg.CalculateConnections((GridNodeBase)node));

And it works now… So you are correct, I will have to adjust so that a cellPosition is in the center instead.

Thank you very much for this quick answer. The problem was deterministic so I just thought it would be something else. Do you know why?



The exact positions of the nodes depends on how you have configured the grid graph settings.
Note that you can also get the node using integer coordinates like

var x = 5;
var z = 7;
var node = AstarPath.active.data.gridGraph.GetNode(x,z);

where (x,z) = (0,0) is always the top-left node of the graph, and (width-1,depth-1) is always the bottom-right node.


Oh, I might look into that.

Once again thank you very much!