Ascending bridge ramp while steering ate a tile of my car.

[Swootch]

Describe the bug

I drove up a bridge ramp at a 45° and tried to straighten out as my car was about halfway up, but my car collided with something and couldn't align itself with the bridge until it was all the way up. A few turns after that I noticed that an entire tile of my car was missing. Every tile of the car was equipped with military composite armor, no debris, the tile just vanished without a trace.

However when I inspected the vehicle with (e), the missing tile is still in that menu.

Steps To Reproduce

1. Drive up a bridge at an angle.
2. Turn while half the vehicle is halfway up (there will be a collision).
3. Vehicle tile goes missing.

Expected behavior

Bridges don't eat cars.

Screenshots

The missing tile:

The missing tile still present when inspecting the vehicle:

Versions and configuration

• OS: Windows
  • OS Version: 10.0 1903
• Game Version: 0.E-4810-g5396506 [64-bit]
• Graphics Version: Tiles
• Game Language: System language []
• Mods loaded: [
  Dark Days Ahead [dda],
  Disable NPC Needs [no_npc_food],
  Alternative Map Key [alt_map_key],
  Bionic Slots [cbm_slots],
  Blaze Industries [blazeindustries],
  C.R.I.T Expansion Mod [crt_expansion]
  ]

Additional context

I can walk through the tile like it doesn't exist, even though the inspection menu says it's still.

The save file:
Echoes of Darkness.zip

[anothersimulacrum]

If you drive your car off of the bridge, does it appear? It may not have ascended.

[Swootch]

Yes, I left the bridge and the tile reappeared. Damn that scared me.

[ZhilkinSerg]

Vehicles are 3D now, so missing parts are usually just hanging one z-level above ground level now.

[wapcaplet]

Confirmed in 0.E-5296-g a883429

This seems a little easier to reproduce with a larger vehicle, like a Humvee (5x7 tiles) but I was able to reproduce it using a City Car (4x4) as well. It took several tries, going up and down the ramp at various angles, but I lost not just 1 but 9 tiles of the vehicle:

The missing tiles persist through a save and load; here is my save game with the disintegrated Humvee:
broken-humvee.zip

Driving back down the ramp allows the vehicle parts to be restored.

[Aivean]

Might be related? #44534

[mlangsdorf]

#45726 didn't fix the issue. I think what is happening is that turning from 60 degrees to 45 degrees (ie, past a sheer point) causes the relevant vehicle tiles to next enter the ramp properly, and so they never move up the ramp. That's why the issue persists across a save and reload; the relevant tiles are actually at a lower z-level.

I'm pondering how to fix it but I think the code that auto-levels a vehicle that partially drives off a ramp might be the solution.

[mlangsdorf]

It would probably be simpler to just disallowing turning while a vehicle is on ramps. The logic for determining that part of a vehicle is incorrectly below a surface is kind of complex.