Bus is going off world

Question.
How to stop a physics enabled vehicle from entering a crashed sim?

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Background.
I am testing a automatic bus that travels around two private sims.

The bus uses the low lag AutoBahn protocol that uses llKey2Name instead of scanners to find the road. https://wiki.secondlife.com/wiki/LSL_Protocol/AutoBahn
I put out a free box at Charissa (211, 228, 117)

The problem is that the bus gets returned to me when it blindly drives into the other sim when the other sim is off line.

I get a IM saying that it was returned because it went off world.

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Options
1. Get the name of the sim and it's status every time the target position changes.

The problem is that the sim could still go down during between the time the script get's the target and when it moves that ~20m.

2. Have a Rezier that checks for the bus every hour and re rezes a new copy.

3. Do both.

My own personal experience with guided AIs and crossing sims is that rezzing a probe object to determine if the next sim is online (or testing ban lines) work great.... provided your vehicle is going slow enough that it doesn't recieve the data after it's moved there. In practical terms, my experiments work great for about a walking speed (.75m/s), anything faster than that is too fast for (my method of) response times and time-out checking for dead sims and ban-lines.


in your own case, since the bus is on a guided path, it knows when it will be crossing the sim and can rez a probe ahead of time to report back the sim's status before the bus reaches the border.