Advice for Huge Terrain Grid

General Grid graph
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I’m looking for the best approach to manage a large terrain grid (8x8 tiles, each 1000m²) using A* Pathfinding. Any advice on optimizing performance and accuracy?

I’m using A* PRO to draw some roads and path over the terrain, basically shouldn’t be complex, but the gird that I’m able to achive is 1024*1024 with a cell of 7.8125.

So I’m using AstarPath and when I init the grid I try to get it smaller but didn’t work:

float worldSizeX = _terrainGrid.GetLength(0) * _terrainGrid[0, 0].terrainData.size.x;
float worldSizeZ = _terrainGrid.GetLength(1) * _terrainGrid[0, 0].terrainData.size.z;
float nodeSize = 2; 
int graphWidth = Mathf.RoundToInt(worldSizeX / nodeSize);
int graphDepth = Mathf.RoundToInt(worldSizeZ / nodeSize);

gridGraph.SetDimensions(graphWidth, graphDepth, nodeSize);
gridGraph.center = new Vector3(worldSizeX / 2f, 0, worldSizeZ / 2f);
gridGraph.is2D = false;

Despite explicitly setting float nodeSize = 2; the cell size remains around 7. I checked the calculations, but I can’t figure out why the grid isn’t reflecting the expected resolution. Could it be an internal limitation of A* or something I’m overlooking.

So maybe a better solution could be to create a grid for each terrain tile, isn’t it?
The terrain is procedurally designed, so the roads have to, that’s why I thought A* would be a good solution, but the grid is too big and lack of details, so often fails on founding a valid path.

Maybe adding a RecastNavmeshModifier would improve performance and helps?
I’m quite lost.

Any advice is very welcome :slight_smile:

  • A* version: 5.3.7
  • Unity version: 6000.1.5
2

Yeah I’d definitely start by switching to a RecastGraph over a GridGraph here. They handle huge areas a lot better. Alternatively, you can also look into the ProceduralGraphMover to make a graph that follows your agent, instead of scanning the entire scene. In your case I’d start with Recast though.

1 Like
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ProceduralGraphMover looks exactly what I need, I could use a much more detailed grid!
Thank you, I’ll test it both! :slight_smile:

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4

And yes. The grid graph is artificially limited to 1024x1024. Large grids use up a lot of memory, so you pretty much never want anything larger than 1024x1024.

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I’m just using it to draw roads and rivers, so a stretched grid at 1024 is still fine, because a single cell is half the width of the road, so I should be fine.:wink:

For the NPC prolly will need something different.