"Diagonal Connections not Supported"

noio · September 16, 2025, 12:46pm

A* version: 5.4.3
Unity version: 6000.0.56f1

When units are navigating a GridGraph, I keep getting an Exception: Diagonal connections are not supported

This does not happen immediately when the units spawn, it only happens a little bit into them navigating the grid. Full stack trace is posted below.

It happens when there’s a couple units on the grid. I’ve made a screen recording below

What does this error mean? I understand if it’s some misconfiguration, but why does it then only pop up when there are many units?

Exception: Diagonal connections are not supported
  at Pathfinding.PathTracer.ResolveNormalizedGridPoint (Pathfinding.GridGraph grid, Pathfinding.Collections.CircularBuffer`1[Pathfinding.GraphNode]& nodes, Pathfinding.Collections.UnsafeSpan`1[T] cornerIndices, Pathfinding.Funnel+PathPart part, System.Int32 index, System.Int32& nodeIndex) [0x0017b] in ./Library/PackageCache/com.arongranberg.astar@9a6b1e585a1a/Utilities/PathTracer.cs:1837 
  at Pathfinding.PathTracer.SimplifyGridInnerVertex (Pathfinding.Collections.CircularBuffer`1[Pathfinding.GraphNode]& nodes, Pathfinding.Collections.UnsafeSpan`1[T] cornerIndices, Pathfinding.Funnel+PathPart part, Pathfinding.Collections.CircularBuffer`1[System.Byte]& portalIsNotInnerCorner, System.Collections.Generic.List`1[T] alternativePath, System.Int32& alternativeStartIndex, System.Int32& alternativeEndIndex, Pathfinding.TraversalConstraint& traversalConstraint, Pathfinding.TraversalCosts& traversalCosts, System.Boolean lastCorner) [0x00174] in ./Library/PackageCache/com.arongranberg.astar@9a6b1e585a1a/Utilities/PathTracer.cs:1900 
  at Pathfinding.PathTracer.GetNextCornerIndices (Unity.Collections.NativeArray`1[System.Int32]& buffer, System.Int32 maxCorners, Unity.Collections.Allocator allocator, System.Boolean allowSimplify, System.Boolean& lastCorner) [0x00122] in ./Library/PackageCache/com.arongranberg.astar@9a6b1e585a1a/Utilities/PathTracer.cs:1490 
  at Pathfinding.ECS.JobRepairPath.Execute (Unity.Transforms.LocalTransform& transform, Pathfinding.ECS.MovementState& state, Pathfinding.ECS.AgentCylinderShape& shape, Pathfinding.ECS.AgentMovementPlane& movementPlane, Pathfinding.ECS.AutoRepathPolicy& autoRepathPolicy, Pathfinding.ECS.DestinationPoint& destination, Unity.Entities.EnabledRefRW`1[T] readyToTraverseOffMeshLink, Pathfinding.ECS.ManagedState managedState, Pathfinding.ECS.MovementSettings& settings, Unity.Collections.NativeList`1[T] nextCornersScratch, Unity.Collections.NativeArray`1[System.Int32]& indicesScratch, Unity.Collections.Allocator allocator, System.Boolean onlyApplyPendingPaths) [0x00102] in ./Library/PackageCache/com.arongranberg.astar@9a6b1e585a1a/Core/ECS/Jobs/JobRepairPath.cs:188 
  at Pathfinding.ECS.JobRepairPath.Execute (Unity.Entities.ArchetypeChunk& chunk, System.Int32 unfilteredChunkIndex, System.Boolean useEnabledMask, Unity.Burst.Intrinsics.v128& chunkEnabledMask) [0x0011e] in ./Library/PackageCache/com.arongranberg.astar@9a6b1e585a1a/Core/ECS/Jobs/JobRepairPath.cs:127 
  at Pathfinding.ECS.JobRepairPath.Unity.Entities.IJobChunk.Execute (Unity.Entities.ArchetypeChunk& chunk, System.Int32 unfilteredChunkIndex, System.Boolean useEnabledMask, Unity.Burst.Intrinsics.v128& chunkEnabledMask) <0x4708a3288 + 0x0005b> in <2aad84f142c446d29831a2af1b8b21fe>:0 
  at Unity.Entities.JobChunkExtensions+JobChunkProducer`1[T].ExecuteInternal (Unity.Entities.JobChunkExtensions+JobChunkWrapper`1[T]& jobWrapper, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) [0x0013f] in ./Library/PackageCache/com.unity.entities@6a355619334f/Unity.Entities/IJobChunk.cs:420 
  at Unity.Entities.JobChunkExtensions+JobChunkProducer`1[T].Execute (Unity.Entities.JobChunkExtensions+JobChunkWrapper`1[T]& jobWrapper, System.IntPtr additionalPtr, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) [0x00001] in ./Library/PackageCache/com.unity.entities@6a355619334f/Unity.Entities/IJobChunk.cs:363

[EDIT] I tried downgrading back to 5.3.8 but now I’m getting Exception: Run more migrations than there are migrations to run. Finished: 4000000F all: 40000007

[EDIT2], I reverted all of my prefabs/assets (using git) to the versions before updating to 5.4, which fixed the migrations error. Also, on A* 5.3.8, I don’t get the “diagonal connections” error.

tealtxgr · September 16, 2025, 3:17pm

Regression maybe? Has your entities version changed at all? Or does it have an update? I’ll tag @aron_granberg here since it didn’t exist before but did after updating.

aron_granberg · September 17, 2025, 8:02am

That’s expected when downgrading. Reverting them using git is the proper solution.

Can you post your grid settings?

Do you have any way to reliably replicate the issue?

noio · September 17, 2025, 8:31am

It happens all the time (on A* 5.4) .

But that’s in my project, I haven’t set up a clean repro.
(I would be willing to share the project with you though, if you’re interested)

Settings below:

aron_granberg · September 17, 2025, 8:35am

Just curious. Does the NotBuildable tag affect the movement of agents?

Do you have any other tags that affect the movement of agents?

pesukarhu · December 1, 2025, 5:13pm

I’m having this same issue. Isometric Grid with Dimetric angle & 0.1 grid size. It happens after pathing around for a bit quite randomly, I can’t figure out how to trigger it every time.

I don’t have any tags at all.

tealtxgr · December 2, 2025, 7:30pm

@noio @pesukarhu can you both post your current versions for the Mathematics, Entities, Burst, and Collections packages? Another thread was having a similar issue and I want to see if dependencies may be related.

pesukarhu · December 5, 2025, 9:11pm

Mathematics: 1.3.3
Entities: 1.4.3
Burst: 1.8.25
Collections: 2.6.3

Stathap · December 16, 2025, 6:34pm

Hello, is there any update on the issue?

tealtxgr · December 17, 2025, 6:55pm

It’s still on the plate If you find any additional info you think would help be sure to post it here

aron_granberg · December 17, 2025, 8:56pm

Yeah, it’s an issue I will prioritize fixing properly in the near future. But it’s a tricky one. Might take a bit of time.

You can work around it by setting Connections = Four in the grid graph settings. But that might not work for many games (and it changes paths quite a bit).

Ralph_S · December 31, 2025, 10:52am

Exception: Diagonal connections are not supported
Pathfinding.PathTracer.ResolveNormalizedGridPoint (Pathfinding.GridGraph grid, Pathfinding.Collections.CircularBuffer1[Pathfinding.GraphNode]& nodes, Pathfinding.Collections.UnsafeSpan1[T] cornerIndices, Pathfinding.Funnel+PathPart part, System.Int32 index, System.Int32& nodeIndex) (at ./Packages/com.arongranberg.astar/Utilities/PathTracer.cs:1846)
Pathfinding.PathTracer.SimplifyGridInnerVertex (Pathfinding.Collections.CircularBuffer1[Pathfinding.GraphNode]& nodes, Pathfinding.Collections.UnsafeSpan1[T] cornerIndices, Pathfinding.Funnel+PathPart part, Pathfinding.Collections.CircularBuffer1[System.Byte]& portalIsNotInnerCorner, System.Collections.Generic.List1[T] alternativePath, System.Int32& alternativeStartIndex, System.Int32& alternativeEndIndex, Pathfinding.TraversalConstraint& traversalConstraint, Pathfinding.TraversalCosts& traversalCosts, System.Boolean lastCorner) (at ./Packages/com.arongranberg.astar/Utilities/PathTracer.cs:1902)
Pathfinding.PathTracer.GetNextCornerIndices (Unity.Collections.NativeArray1[System.Int32]& buffer, System.Int32 maxCorners, Unity.Collections.Allocator allocator, System.Boolean allowSimplify, System.Boolean& lastCorner) (at ./Packages/com.arongranberg.astar/Utilities/PathTracer.cs:1493) Pathfinding.ECS.JobRepairPath.Execute (Unity.Transforms.LocalTransform& transform, Pathfinding.ECS.MovementState& state, Pathfinding.ECS.AgentCylinderShape& shape, Pathfinding.ECS.AgentMovementPlane& movementPlane, Pathfinding.ECS.AutoRepathPolicy& autoRepathPolicy, Pathfinding.ECS.DestinationPoint& destination, Unity.Entities.EnabledRefRW1[T] readyToTraverseOffMeshLink, Pathfinding.ECS.ManagedState managedState, Pathfinding.ECS.MovementSettings& settings, Unity.Collections.NativeList1[T] nextCornersScratch, Unity.Collections.NativeArray1[System.Int32]& indicesScratch, Unity.Collections.Allocator allocator, System.Boolean onlyApplyPendingPaths) (at ./Packages/com.arongranberg.astar/Core/ECS/Jobs/JobRepairPath.cs:188)
Pathfinding.ECS.JobRepairPath.Execute (Unity.Entities.ArchetypeChunk& chunk, System.Int32 unfilteredChunkIndex, System.Boolean useEnabledMask, Unity.Burst.Intrinsics.v128& chunkEnabledMask) (at ./Packages/com.arongranberg.astar/Core/ECS/Jobs/JobRepairPath.cs:127)
Pathfinding.ECS.JobRepairPath.Unity.Entities.IJobChunk.Execute (Unity.Entities.ArchetypeChunk& chunk, System.Int32 unfilteredChunkIndex, System.Boolean useEnabledMask, Unity.Burst.Intrinsics.v128& chunkEnabledMask) (at :0)
Unity.Entities.JobChunkExtensions+JobChunkProducer1[T].ExecuteInternal (Unity.Entities.JobChunkExtensions+JobChunkWrapper1[T]& jobWrapper, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) (at ./Library/PackageCache/com.unity.entities@42c4e852ffb4/Unity.Entities/IJobChunk.cs:421)
Unity.Entities.JobChunkExtensions+JobChunkProducer1[T].Execute (Unity.Entities.JobChunkExtensions+JobChunkWrapper1[T]& jobWrapper, System.IntPtr additionalPtr, System.IntPtr bufferRangePatchData, Unity.Jobs.LowLevel.Unsafe.JobRanges& ranges, System.Int32 jobIndex) (at ./Library/PackageCache/com.unity.entities@42c4e852ffb4/Unity.Entities/IJobChunk.cs:364)

I’m having the same issue, I just recently bought the asset and only have a basic setup. No Optimizations. Also happens after a while of pathing around an agent. Should we downgrade to a previous version?

Unity 6000.0.59f2

Mathematics 1.3.2

Entities 1.4.3

Burst 1.8.25

Collections 2.6.3

tealtxgr · December 31, 2025, 5:37pm

I’d try this workaround if you haven’t yet/are able to.

Otherwise if you want to downgrade I’d just take note of the warnings mentioned by Aron as well as the edit posted by OP.

Ralph_S · January 1, 2026, 2:18pm

Ok, setting Connections to Four seems to work for now, I haven’t seen how much of a negative effect it has yet on path calculation. I’m going to keep watching this thread for any updates.

aron_granberg · January 8, 2026, 12:23pm

Hi

I found another tricky bug relating to this. I’ll include a fix in the next update.

The fix is quite simple, though. So as a workaround, until the next update, you can comment out the following lines in GridGraph.cs:

// Only allow taking a diagonal move if we have at least 2 steps remaining
nextNode = remainingSteps > 1 ? fromNode.GetNeighbourAlongDirection(ndir) : null;
if (nextNode != null && (nextNode == prevNode || !traversalConstraint.CanTraverse(fromNode, nextNode))) nextNode = null;

// Taking a diagonal takes us one additional step closer to the target node compared to an axis-aligned move.
if (nextNode != null) remainingSteps--;

Ralph_S · January 9, 2026, 12:26pm

Thanks, I can’t update the file currently, since it’s read-only (unity package folder). “Connections = Four” does also fix it for now, I haven’t seen any negative side effects so far. Looking forward to the next update though!