Mass AI Traffic Crashes

Development Programming & Scripting AI
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This is the Error I am Getting. LoginId:04685f2a44a5ccc3368c6cb072a67f82
EpicAccountId:eddf8767851b43fab71524d0fa23b1bb

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000020

UnrealEditor_MassTraffic
UnrealEditor_MassTraffic
UnrealEditor_MassEntity
UnrealEditor_MassEntity
UnrealEditor_MassSpawner
UnrealEditor_MassSpawner
UnrealEditor_MassSpawner
UnrealEditor_MassTraffic
UnrealEditor_MassSpawner
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_UnrealEd
UnrealEditor_UnrealEd
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll

I am was trying to follow the YouTube tutorial link below

The only part of the tutorial i was not able to execute the following console command “ai.traffic.parallelize”
As it is not there in Unreal engine 5.1. Please help me to resolve this problem. Thank you for your time!

1 Like
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hi @HyperShade780

Unfortuntley this could be a wild one to figure. Access Violations mean unreal has attempted to access memory it either isnt allowed to, or is locked by another program.

One thing you can try is switch off all AV software and test.

What gfx card and what system memory do you have by chamce?

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I have RTX 3090 5900x Amd Processor and 64 GB ram 3.5 TB Hard Disk. I am only using Windows Defender

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Hi! I had the same crashing problem (using UE5.2.1). Did you make sure to set the correct “MassAI Traffic traits” mentioned in the screen shot located in the video details? If even one of them is missing, the editor is going to crash. This was not explained properly in the video.

1 Like
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We had the same issue when we created a vehicle spawner in the blueprint with MassSpawner as its parent.

For anyone who has experienced a similar problem, try to delete the Saved folder under your project (be sure to back up first).

The PostSpawnProcessors property in MassSpawner.h has a UPROPERTY macro before it (Line 138) for an unknown reason.

UPROPERTY()
TArray<TObjectPtr<UMassProcessor>> PostSpawnProcessors;

As such, Unreal will try to restore the value in the array on the next run. However, it only restores the values but does not initialise the processor. Hence some fields in the processor are nullptrs, and accessing it will cause EXCEPTION_ACCESS_VIOLATION.

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even after I did that, it still crash… any update on the subject?

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Add to traits and in 5.1.1 all work
MassAI_traffic_Traits

2 Likes
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thank you, I will test it for 5.2 and up and see if it works

9

How do I add all these lines, the last 3 I haven’t managed to do yet?