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Collision physics development?

Discussion in 'General Discussion' started by SuchSneak, Aug 1, 2020.

  1. SuchSneak

    SuchSneak
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    Edit: I forgot to mention this issue is something the devs have significantly improved over the life span of development. I'm just hoping it continues to improve and curious how the devs are planning to tackle it.

    Have the devs stated any plans to address vehicles collisions getting stuck together before release?

    The issue surfaces when two entities with collision surface phase through one another at high speeds. Less of an issue with the terrain because the ground is so thick the vehicle simply gets pushed back out. If we use a pole however, then the problem is super obvious. Once the vehicle phases through the pole we now have collision surfaces that will push against eachother preventing the vehicle to bounce back off.

    A easy possible solution would be to avoid using thin objects but that would mean car vs car collisions would result in a downgrade.

    A harder fix would involve making the collision system somehow more accurate, if we could avoid objects phasing through eachother the problem would go away but I don't think that's realistic unless the devs have some tricks up their sleeves.

    I'd like to know if this is something the devs are thinking about.
     
    #1 SuchSneak, Aug 1, 2020
    Last edited: Aug 2, 2020
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  2. P_enta

    P_enta
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    I agree. Falling down a cliff and crashing into a tree just to see it halfway through the car without actually splitting it in half is a huge break of realism for me.
     
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  3. Kirahl

    Kirahl
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    Years ago this issue was much bigger, most collisions between cars that were more than a fender bender resulted in them becoming welded to one another. I imagine improvements will come, but currently I find it acceptable for the development stage we're at, I rarely run into vehicles sticking to one another these days (tho I will admit poles are still somewhat of an enemy).

    As for what could be done, I think the simplest thing would be to increase the physics update rate to prevent objects phasing through each other. This comes with it's own issues however, such as a big bump in CPU horsepower needed, potential instability and all simulated objects requiring tuning (not sure about this one). Other than that, some tricks and such, like what fixed it years ago.

    I don't think will ever happen, the Jbeam system doesn't allow for splitting like that, look at any vehicle that can 'break' such as the Pigeon, it just disappears where it breaks. Can newer cars even do that tho? I know the older cars in the game can split in a sense, the body frame parts will separate and fly off in bad enough collisions.
     
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  4. P_enta

    P_enta
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    Having fractal simulated splits and cracks in the cars components would be amazing but we are years away from that
     
  5. Kirahl

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    It's the dream, tho the issue there might be the actual structure, you'd need to generate the rigidfying structure which I imagine would be extremely difficult or just not possible. That's a very complicated structure to just generate on the fly.
     
  6. P_enta

    P_enta
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    One thing that concerns me is maybe we are hitting a physical limit on computer development. Most CPU’s are on the 7nm process, and in probably 5 - 8 years we will be already down to 1nm. I doubt we can get much smaller than that. With something as big as the downsizing of transistors being lost computer development might go much much slower.

    Or I could be wrong, it’s kinda tin-foil-hat-y
     
  7. Kirahl

    Kirahl
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    True, we will soon run into a limit with CPU node size, however the 7nm is misleading, the actual transistors are bigger than that, it's just marketing talk now. There's a few ways we could go, AMD (and Intel to a lesser degree) are increasing core count, which helps BeamNG a ton, but won't help a single vehicle, due to each Jbeam object using a single thread. Single core performance can come from architecture improvements too, look at AMD, huge leaps, Zen3 is said to be 15%~ faster while on the same node size, albeit an improved 7nm.

    I see a switch from silicon at some point happening which would allow the transistors to switch a lot faster and thus increase clocks, I imagine this will take a long time since microchips have been silicon since their beginning. There's a ton of other stuff too, like L4 Cache, 3D stacking of CPUs, better parallelisation in software (near impossible with physics, each steps requires the previous one). Improvements could come from change of ISA too, such as moving from x86 to ARM or RISC-V like Apple is doing with it's newer computers. The future is exciting for how we'll get around quantum limits of integrated circuits.

    I don't have a very deep knowledge on this stuff, so forgive any ignorance.
     
  8. P_enta

    P_enta
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    You make some really good points.

    Offtopic but how is the 3900X working for you in BeamNG?

    I was thinking of getting the 3950X for 4 more cores but maybe I don’t need it?
     
  9. Justy4WDTURBO

    Justy4WDTURBO
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    Don't get Zen 2 unless on sale, Zen 3 is right around the corner.

    t. is getting a 3950X late this year because no way in hell i'm paying €1000 for the 4950X lol
     
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  10. Kirahl

    Kirahl
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    It's fantastic, enough single core performance for the most complicated vehicles and can handle 24 cement trucks at about 50-60FPS. The amount of traffic that spawns with it is insane.
    You're right, Zen3 should be announced real soon and should be a nice performance boost over Zen2 so wait for that if you can. Hopefully they have a better supply this time, took me 3-4 months to get my CPU after it released.
     
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  11. Aboroath

    Aboroath
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    More compute power will always help with the collision mesh sticking issue. As these meshes get more and more detailed the mathematics involved in their proper operation is mind boggling. IIRC the devs, in what I assume was a temporary fix for the tree/pole issue, simply enlarged the collision meshes.
    Not sure where that stands today as I see more tree sticking lately. As for cars splitting in two, I would suspect the engine would at some time in the process have to turn one vehicle into two, transferring all associated state information properly to each vehicle piece. Merely an imaginative assumption on my part but I think real vehicle splitting is a long way off regardless.
     
  12. Sithhy™

    Sithhy™
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    They are improving that update by update. Go look at videos from like 5-6 years ago & compare them to now. The improvements are huge. The devs are doing what they can, but they aren't magicians
     
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  13. SuchSneak

    SuchSneak
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    I totally agree, I forgot to add that this issue is much better than it used to be from launch. The work the devs have put in so far is more than acceptable, I just hope the work in this area continues.
     
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  14. CaptainZoll

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    I think I remember reading something about beam collision becoming a thing, (it might have already been implemented?) if they get that to work, it would be interesting to see how much that improves the physics.
     
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  15. Justy4WDTURBO

    Justy4WDTURBO
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    A place I would like to see more work is clipping of body parts (such as the engine clipping through the firewall in hard crashes) and more realistic deformation of older vehicles, IMO the Covet deforms far too little for such a old car.
     
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  16. SuchSneak

    SuchSneak
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    Official cars are quite optimized when it comes to the actual collision/beam physics model. The interior/engine are ethier not modeled or very crude. If devs modeled the interiors it would certainly up take a performance hit. Take a look at CrashHard's 8x8 truck mod for example, I'll quote the mod page here:

    "(This is a very heavy mod to run, almost every part of the truck have its own J-beam structure, and they all collide with each other. And remember one vehicle will only use one of your CPU Cores)"


    My pc has a hard time running the mod and I dread the thought of all the cars being this demanding. I think this is only an issue currently because of how beamng apperently assigns one core too one car. So who knows, maybe devs will improve this in the future.
     
  17. tobias95ng

    tobias95ng
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    i would say that thin objekts should be destroyable props so we get rid at least of them
    i miss a dynamical destroyable eviorment in beamng a lot.
    like destroyable light posts, gates telephone post ec.

    buy the way i was alwayws wondering is it possible to activate the colission of those props only if a car is in its direct aproximety

    that wold save a lot of cpu power wouldnt it ?
     
  18. CaptainZoll

    CaptainZoll
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    I remember them talking about a "physics sleep" system like what RoR has a few years ago, nothing probably came of it though.

    though it's not probably high on the priority list, a workaround would be a system like the traffic system, that respawns light poles and signposts on specific parts of the map. though it has the problem that you knock a pole down, drive away, it despawns, come back and it's reset again.
     
  19. estama

    estama
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    While we don't yet support full physics sleeping, different subsystems can sleep on their own. For example aerodynamics can turn itself off when an object is stationary. Collision subsystem can also do multiple different forms of sleeping depending on the situation.

    You are right. We are already starting to feel the need to start deciding where to use the limited computational resources. Throw the CPU resources towards simulating fewer but more complex vehicles or towards simulating more but simpler vehicles? Right now the decision is being implicitly being made by limiting the complexity of a single vehicle to what an average CPU core can cope with and we scale with more CPU cores. We could have made a different trade-off by choosing to throw all the CPUs into a single vehicle's simulation.

    Whenever we hit the CPU fabrication limits, we'll have a more or less hard limit on how much computational capabilities in a singular machine will be available. We have some ideas about how to continue after this situation arises but they'll require a lot of additional research.
     
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  20. TYLERTJ

    TYLERTJ
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    I just want to see better low speed impacts, like backing out of a parking spot and hitting a wall resulting in a caved in bumper corner. 1507C655-0CB6-41A8-B00E-0C508CB4D02D.jpeg
     
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