Excessive Centrifugal Forces on Wheels causes Unexpected Deformation

Hello,

I first would like to disclaim myself from negligence to verify that the bug I encountered was already reported; I have not found a similar thread that describes the situation which I encountered.

I believe to have found a glitch, that occurs on almost all of the automobiles, where wheels without tires (hypothetically this could apply to tire-clad wheels but the simulation keeps resetting due to instabilities) that explode, from excessive stress from centrifugal forces, distort not into pieces of shrapnel as one would expect, but into nearly infinitely extending planes that sometimes obscures all of your vision.

Below is an image detailing the effects of the glitch.


Reproduction of the glitch:

1. From the 'Free Roam' menu, select any level (this glitch occurs regardless of level loaded)
2. Select any car/truck from the list that allows removal of the differential; except vehicles that have AWD configurations.
3. The vehicle must be positioned where the driving wheels do not touch the ground or any surface that would conduct friction at any time.
4. In the Vehicle Config menu --
   1. For the the driving wheels, set the tire drop-down box to 'empty'
   2. set the differential drop-down box to 'empty'
5. Accelerate the vehicle

• It is at that point where the glitch can be observed.

Of course, almost any situation, realistically, would not have wheels rotating with such velocity as to reach the point where they explode from sheer centrifugal force.
But I would imagine that if such a scenario were to occur on a wheel, that it would explode into small shattered pieces, rather than having polygons stretch nearly infinitely to where you couldn't see anything.

I hope that my report, made consciously with due diligence, provides meaningful feedback to the developers.

 

Well said! This is an extremely weird bug.

Did you try a couple of things like:

• Deleting the cache? (Found here) Documents/BeamNG.drive/cache0.5.3.1. Delete cache0.5.3.1
  • If this doesn't work try deleting the BeamNG.drive folder in your Documents (the place where all settings and mods are held)
• If this doesn't work, reinstall the game entirely
  • Make sure you delete the BeamNG.drive folder in your Documents just to be sure it is as clean of an install as you can get.

 

Wow, interesting find. Out of curiosity, how exactly did you find this bug? It is just so obscure, and seems really unlikely to occur during normal gameplay.

 

Read how to recreate it. That's how he found it. Why he did that is the real question.

OT: Mesh breaking isn't on for the hubs. Honestly, I wouldn't expect the devs to actually have it on because I don't think they expected something like this to happen...

 

Yeah, you are right. I meant to say that. It reminds me of game testers that run into walls everywhere and do random things looking for bugs.

 

Erring on the side of caution, I have decided to skip clearing the cache and go ahead with a full removal of the game. After removing the beamng.drive folder and then reinstalling the game, I have been able to reproduce the bug successfully. Here is a screenshot for evidence. The level that this was taken on is Puregrid.

I like to push things until they break (got that from my mom's side of the family), it's how I broke my first computer when I discovered overclocking and decided never to do it again because I almost burned my mother's house down (rest in peace modified eMachines w/ AMD Athlon 64). I was also specifically inspired by a video on YouTube where an experiment was being demonstrated showing the maximum rotational force that a CD could sustain before it would explode.
Besides, who wouldn't want to push things to the limit in BeamNg?, it's a computer simulation; the worst that could happen is that you freak out when eldritch polygon abominations consume all of your vision and give you nightmares.

Actually, I discovered this bug a while ago, but I hesitated on reporting it because I was shy and nervous about writing something to the forums, especially a bug report, and get punished because I did something wrong.

 

I feel beams should break after being stretched a certain amount, but I remember one of the developers saying there were issues with this.

Will be interesting to see what the BeamNG team says about why this happens, might be able to learn a few things here.

 

Tearing and fragmenting realistically isn't really possible in BeamNG, which is down to the fundamentals of the physics simulation. All physics objects are made of nodes, infinitely small points in 3d space, and beams, which almost always connect two nodes. Hundreds of nodes and thousands of beams form a low fidelity skeleton of the object. The visible mesh, the flexbody, is tied to this skeleton. Spooky.

The wheel and tyre beams do break, and in your case fail catastrophically, launching untethered nodes out into the world with whatever angular momentum the node had before the wheel beams failed. Since the wheel flexbody is tied to these nodes, it stretches out as far as the node is launched, giving the appearance of a graphical glitch. Not much can be done aside from hardcore mesh tearing, which would look quite ugly under any other circumstance, as entire chunks of the wheel go missing when damaged.

 

When I conducted the 'catastrophic failure' experiments on wheels clad with tires, the tires usually would have the outer wall expanding outward, while the inner wall remaining the same circumference, before complete structural failure of the tire would occur, however the tires' structural failures would not cause their respective flexbodies, as you described, to completely obscure all visible angles of the in-game camera. As an added note, the latest update at the time of posting, 0.5.3.2, has introduced a new behavior where shortly after the tires rupture from the centrifugal forces, the simulation would detect an instability and reassemble the vehicle and pause the game.
I would imagine that the wheels would've exhibited a somewhat similar behavior where the wheel would at least disappear in a similar fashion to the tires.

Your explanation, though, is very intriguing and helps to 'fill in the gaps' of my understanding of the conceptual workings of the Beam engine, thank you.

 

You're quite welcome!

The tyres might have mesh tearing enabled then, but I don't think that's the case for the rims. That's really the only explanation for the rim flexbodies to freak out, but not those of the tyres.

Forgot to mention earlier that removal of all diffs effectively changes the final drive to 1:1 or something absurd, which is how the driven wheels reach the speeds they do. Has been a bug since forever.