Editing GridGraph at Runtime

General Grid graph
#1

Hi there,

I have set up a gridgraph with the following settings:

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image468×532 25.9 KB

I Instantiate a cube prefab and assign a random position to it every 1 second, and consider it an unwalkable part of the graph.

private void Refresh()
    {
        _obj.SetActive(false);
        var bounds = _obj.GetComponent<Collider>().bounds;
        var guo = new GraphUpdateObject(bounds);
        guo.updatePhysics = true;
        AstarPath.active.UpdateGraphs(guo);
        
        _obj.SetActive(true);
        _obj.transform.position = new Vector3(Random.Range(0, 10f), 0f, -Random.Range(0, 10f));
        bounds = _obj.GetComponent<Collider>().bounds;
        guo = new GraphUpdateObject(bounds);
        guo.updatePhysics = true;
        AstarPath.active.UpdateGraphs(guo);
    }

I expect the first part of the code to remove the previous position of the cube on the graph, and the second part, add a unwalkable hole on the graph.
Unfortunately the result I get is multiple holes that represent the change done during the previous refresh… No holes get cleared up.

Is this process not synchronous? is it due to multithreading?

#2

Could it be related to that thread? Cannot seem to scan graph from script
Unfortunately calling Physics.SyncTransforms
cause a weirder issue and never seem to update the graph at all.

#3

It seems to be related to that issue:

I found three options to fix this issue:

1- Wait for the end of the frame (I do not like this solution as I need to refresh my grid synchronously)
2- Set Physics.autoSyncTransforms = true; (Physics.SyncTransforms doesn’t seem to be enough)
3- Refresh collider by calling
collider.enabled = false;
collider.enabled = true;

#4

Hi

UpdateGraphs does indeed not actually update the graph. It just puts it in a queue and the graph will be updated later. This is done for performance.

You can force the graph to be updated immediately by calling AstarPath.active.FlushGraphUpdates();

See https://arongranberg.com/astar/docs/astarpath.html#FlushGraphUpdates