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Some AI-driven vehicles cannot cross bridges
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Description

Some vehicles cannot drive across some bridges when driven by AI. This behaviour is strongly dependent on vehicle type. As far as I know, the only vanilla vehicle regularly affected is the quadbike, but roughly 50% of CUP wheeled vehicles have the same problem and some of the RHS UAZs.

An example of an affected bridge is Altis 100128 SW->NE, but there are many others with different models on different maps. In some cases one direction of travel is worse than the other.

I've checked the following potential causes:

  • setMass and setCenterOfMass don't help.
  • Hiding objects near the bridge doesn't help.
  • Couldn't find any plausible vehicle config differences.

What I did find is that the model center height (_veh modelToWorld [0,0,0]) # 2 is strongly correlated with failure: Vehicles with <1m model center height will almost always fail, while vehicles with >1.5m will tend to cross bridges without problems. This suggests that the collision prediction logic has a false dependence on the model center, which seems like it might be a straightforward fix.

Details

Severity
Major
Resolution
Open
Reproducibility
Always
Operating System
Windows 8 x64
Category
AI Pathfinding / Motion
Steps To Reproduce

Spawn an AI quadbike SW of the Altis bridge at 100128. Order it to drive over the bridge to the NE. 90%+ of the time it'll swerve violently into the railing when approaching the far end.

Additional Information

This is quite bad for Antistasi because we need AIs to be capable of driving semi-reliably on roads. Probably shelving CUP support until this is fixed.

Event Timeline

jaj22 created this task.Jul 10 2022, 2:13 AM
jaj22 added a comment.Wed, Jul 20, 4:13 PM

Added a couple of trivial example missions with Altis and CamLaoNam bridges. Just start the mission and watch. Quad bike swerves violently to the right, about 2/3 of the way across each bridge.

pcc added a subscriber: pcc.Wed, Jul 20, 8:53 PM