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Contact physics

Discussion in 'ACC General Discussions' started by Jynnantonix, Jun 26, 2018.

  1. Jynnantonix

    Jynnantonix Simracer

    Ac's contact physics have always in my view been it's weakest point in the physics department. It feels like other cars have no mass on contact and either you or they are literally bounced off. It makes one much more worried about rubbing paint in a tintop than I think you need to be.
    Having played wreckfest recently it really drove home how fantastic contact physics can be when done right. The cars feel like they have the right amount of mass and react to contact in a very believable way. (The damage model is also simply sublime, however I don't feel this is very important in a racing sim as nobody is going to drive their car until it resembles a squashed in coke can as you can do with much hilarity in wreckfest)

    Just hope this is a point that is going to receive some much needed attention in ACC.
     

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  3. chakko

    chakko Alien

    When you look at this video, at 40:40, it looks like AC's collision model:



    Hope that Kunos can improve it as well. One of the few weak points in AC.
     
  4. TDS

    TDS Alien

    It was a very little bump, doesnt look like bad collision physics to me, both cars survived and they unsettled kinda of realistically to my eyes. They should have unsettled more tho. Too much mass now maybe?

    Anyway ot Doesnt look like Ac1 collision physics at all.
     
    Last edited: Jun 30, 2018
  5. chakko

    chakko Alien

    In my opinion, they should both unsettle a bit more. When you take a look at such bumps in real racing, it seems like they lose more grip. I'd say that the bumped car would have at least gotten a bit of oversteer (you know, the front car loses grip on the rear, if pushed). In the video, nothing really happens.

    In AC, it often was like this: You divebomb someone, and bang into him while both cars steer in. You spin the car out, and the guy you divebombed drives on as if nothing happened. I would like to be a bit more specific, but, i don't understand the physics side of collisions too well, and i can only go by what i always observed in onboards in real racing, and, even smaller bumps unsettle the car quite a bit. I have full faith that the guys at Kunos are well aware how to make a realistic collision model, i just think they should spend some time with it, and improve what is there at AC. Because it really isn't very good.

    Oh, and the sound of the collision is quite lame also, but, that wouldn't be my first priority.
     
    Last edited: Jun 30, 2018
    TDS likes this.
  6. TDS

    TDS Alien

    Yep you replied as i was editing . I also think they should unsettled more... But it doesn't looks lokl ac1 physics at all.
     
  7. chakko

    chakko Alien

    I don't know, could be. I don't know what they changed about the collision model compared to AC.
     
  8. mms

    mms Alien

    IMO it's difficult to get the collisions right. During a collision some of the energy is absorbed by the car's body (which also bends, making the collision less harsh, but also more dynamic in nature), the rest gets split between the two cars.

    The issue is with the absorbed energy, you either have a highly accurate damage model and you can calculate it from there (if you have the CPU power of course), or you need lots of collision data from real life and try to interpolate what's missing. And I don't think this data is available, and it would probably cost too much for Kunos to crash some GT3's in order to get the data they need :D
     
  9. ShredatorFIN

    ShredatorFIN Alien

    For truly bad collisions check Automobilista. I mean the visual damage model on severe contact is better than AC1, but collision detection is abysmal. Cars phase/glitch on light contact with AI, very immersion breaking and perhaps biggest flaw of Automobilista. Contact physics in AC seem rock solid compared to that.

    But I do hope visual damage is more detailed in ACC than in AC. Maybe it would help with the "weighty" feeling of contacts if some parts of chassis actually give in, and visibly break. Instead bouncing off. Not like in Wreckfest that isn't reasonable, but something little
     
    Last edited: Jun 30, 2018
  10. BrunUK

    BrunUK Alien

    A middle ground would be to attribute an 'energy absortion' parameter to various areas of the collision model. Nose to bumper collisions would be relatively 'soft', but side to side less so. Even if those were derived by trial and error rather than specific data, it would be better than the 'billiard ball' contact of AC.
     
  11. mannitom77

    mannitom77 Racer

    I'm pretty sure I read somewhere that ACC has no loose parts or big damage because of licensing rules. I think same goes for many other racing titles as well.
     
  12. Jynnantonix

    Jynnantonix Simracer

    Just watch some of this to see collisions done right. Bugbear have done it, not saying it's easy but hope Kunos can too.



    edit: And yeh, if I had to guess whats wrong with Ac collisions, its that it doesn't feel like there's any modelling of chassis flex to absorb some of the impact, so you just bounce off like a bouncing ball. If they could model some that impact absorption without the visual deformation, seems like a good compromise.
     
  13. D.Jankovic

    D.Jankovic Alien

    Would be cool to have bumpers damage maybe so if you hit somebody it can go loose or fall of completlly. Witch would start FCY maybe and than it just takes random ammount of time before that part gets cleared if it is on the track :D

    I know i know i go overboard sometimes hahha
     
  14. chakko

    chakko Alien

    As far as i read, that is not true at all (didn't Stefano actually wrote that?). iRacing will come up with a pretty extensive damage model at some point, for example.
     
  15. chakko

    chakko Alien

    Ew, no. Not solid at all. For a "solid" collision model in sims, check out iRacing and Race 07. Not saying that they're perfect, but, they're quite a lot better. As others have suggested, Wreckfest would be a game to check out some really nice collision model.
     
  16. ShredatorFIN

    ShredatorFIN Alien

    Are you guys seriously asking for Wreckfest level damage model, or anything close....in ACC? Time for reality check. Wreckfest main selling point is the damage model, their whole ROMU engine (means literally WRECK in Finnish) they worked on for over 5 years, is built around it. Versus ACC, which will have AI cars using same physics as player car, which are probably alone more complex than anything in Wreckfest

    And sure, AC collisions aren't perfect, mentioned AMS as an example how it could be a lot worse. And AMS is despite that one of the absolute best sims, which is what I was trying to hint at... collision physics aren't the most important thing in a game where avoiding collision is everything (or your MP safety rating will go down)

    Sure I hope they improve collision physics to be less bouncy. And hope they improve damage model (visual and physics) as it's part of endurance racing, but comparing to Wreckfest is insane. Unless you meant the actual collisions, not the damage model? But aren't they intertwined too. Just don't get why you use Wreckfest as an example instead of sims that are in similar category as ACC (like iRacing and Race 07), damage like in Wreckfest is not gonna happen
     
    Last edited: Jun 30, 2018
    Ace Pumpkin and mms like this.
  17. Jynnantonix

    Jynnantonix Simracer

    Please see my OP, I specifically mentioned the contact physics and said about the damage model

    "The damage model is also simply sublime, however I don't feel this is very important in a racing sim as nobody is going to drive their car until it resembles a squashed in coke can as you can do with much hilarity in wreckfest".

    So no I'm not suggesting a damage model like that. I strongly disagree with your statement about contact physics not being important, when a tiny bit of contact that would be irrelevant in the real world sends you spinning into the barrier in the sim, that is VERY important in a race sim.
     
  18. Whipdiddywhip

    Whipdiddywhip Simracer

    damage is very important in a sim, at least the impact of it on a race, nobody expects wreck fest damage levels, but iracing has shown the importance of it and without a good damge model the online becomes a bit of bumper cars online
     
  19. Poguinhas

    Poguinhas Alien

    As bad as the collision physics are the damage physics. Rub your door on armco and get a red rear end. Damage on AC1 is just ridiculous.
     
    Pirro, mESCx and LChaves like this.
  20. ShredatorFIN

    ShredatorFIN Alien

    Yeah your post was worded reasonably. But I got the feeling from some others posts like they actually imagine ACC (or any other driving sim, that isn't focused on wrecking cars) will have similar damage as Wreckfest

    Also, I didn't say contact physics aren't important. I said I hope they will be improved. But there is difference between improved contact physics, and "take a look at how Wreckfest". Wreckfest cars have feeling of mass on contact, probably in big part due to how the movement energy bends metal of both cars. Instead the cars bouncing off each other, they merge, bend and dampen the collision. Is it even possible to achieve quite similar feel of mass, without the soft body feature
     
    Last edited: Jun 30, 2018
    mms likes this.
  21. chakko

    chakko Alien

    I don't. I just think that it would be a good reference point, to build something decent. I fully agree with you that such arcade racers have a totally different focus, and much more manpower at hand (even though i really don't know if Bugbear is much bigger than Kunos).
     
    ShredatorFIN likes this.

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