Are you sure you aren't hosting a friends only or private server, single player has no settings for auto removal of abandoned.

There are three settings when you start a game, no, friends only, public, no is for single player.

Nope, I was on single player, not private.

I have no idea unless your computer performance is maxing out, fps drops and they are falling through the ground or something like that.

That is my guess, creations are falling through map and hitting the killzone under the map and disappearing. Next time you see it happen immediately check map for it and watch it disappear as it reaches the killzone.

Careful when you reload. If your looking at seat and press R, it will disappear.

This is happening to me too. It only seems to happen after they get partially destroyed, and then they just disappear.

Originally posted by Ninja Nolan:

This is happening to me too. It only seems to happen after they get partially destroyed, and then they just disappear.

My guess it's gotta be some setting that deletes destroyed vehicles. I'm not currently aware of such a setting, but it's possible that it may be there, since I haven't bothered looking so far.

I still cannot reproduce in single player.

I have discovered when hosting you can set Zero as the amount of the time increment which to some players mean it is off, it is not, setting of Infinite in the type of increment means it is off.

If I had to guess what's causing it, I would say that maybe when the seat of the vehicle gets blown up, it can clip through the ground then fall through the killzone

I have completely undamaged buildings and even if I am staring straight at them they just disappear without a trace they are were floating.

I had it happen once in single player, it was very rare for me but i caught it in the act, i have no idea what caused it as it only happened once.

Most of the time it happens when something reaches a certain point of damage, but sometimes it gets blown completely apart but don't despawn. That's 1.8 for ya.

even though this post is 2 years old, the reason vehicles despawn in singleplayer on newer versions is if the driver seat falls through the map into the void

When it happened to me i was in the middle of a long session of project tweaking, tweak in the editor then spawn to see the results and repeat, it just happened out of nowhere, with no seat involvement, it is some kind of transient issue that has been an extremely rare occurrence for me.