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    Horrible Car Physics

    hello

    edit:
    this thread has become so massive ill try to gather important posts here,

    New answerhub post with test project download here
    https://answers.unrealengine.com/que...cs-issues.html
    demonstrates car launching into the air and stationary car refuses to move on impact


    Issues still present:

    The main issue still remaining
    car launching into the air

    Under investigation by Epic! UE-21990

    video
    https://forums.unrealengine.com/show...l=1#post183110
    PVD files of this issue
    https://forums.unrealengine.com/show...l=1#post183738
    https://forums.unrealengine.com/show...l=1#post184760
    issue shown in Physx SDK
    https://forums.unrealengine.com/show...l=1#post200808
    on Nvidia Developer Zone
    https://forums.unrealengine.com/show...l=1#post202874
    same problem, same physics, different engine
    https://forums.unrealengine.com/show...l=1#post271932
    old answerhub, unresolved!
    https://answers.unrealengine.com/que...ange-jump.html

    Stationary vehicles refuse to move on impact

    UE-21990

    https://forums.unrealengine.com/show...l=1#post181845
    video
    https://forums.unrealengine.com/show...l=1#post182101
    where the problem lies in the physx sdk
    https://forums.unrealengine.com/show...l=1#post184466

    strange 'Magnet' effect

    Under invesigation by Epic! UE-21941

    https://forums.unrealengine.com/show...l=1#post312165
    https://forums.unrealengine.com/show...l=1#post316518

    Falling through the floor
    https://forums.unrealengine.com/show...l=1#post355827

    character can 'ping' vehicles into space just by touching
    https://forums.unrealengine.com/show...l=1#post368831

    Stuff thats been Fixed:

    video showing suspension rising and COM offset issues *Fixed
    https://forums.unrealengine.com/show...l=1#post161849

    Wall Riding, possibly due to COM issue
    https://forums.unrealengine.com/show...l=1#post162812

    Incorrect Drag calculations *Fixed
    https://forums.unrealengine.com/show...l=1#post181786


    original post:

    as the title says, the car physics are really quite terrible.
    i recently played with the 'advanced' ahem.. vehicle in 4.5 preview and was kind of expecting some improvement on the normal one.
    sadly, its even worse, sure the suspension looks visually different but the physics is almost non existent. also 'suspension force' or whatever it was has gone from the wheel properties, so how do you get the car to lean? (edit: its in the wheel blueprints)
    also why does the car raise up as it gets going faster?

    has anybody found the cause of the mystery self up-righting?

    i have started making my own vehicle using a physics asset with constraints but i cant get the wheels to spin any faster than about 10 mph.
    anyone working on a decent car?

    please Epic, whats going on with the physics?
    are there any planned improvements or anything?

    cheers
    459
    Yes Please
    96.08%
    441
    No Thanks
    3.92%
    18
    Last edited by tegleg; 10-13-2015, 05:03 AM.
    tegleg.co.uk - indie electronic music label
    Android + HTML5 WIP Physics Game
    PC Games - Android Apps

    #2
    Originally posted by tegleg View Post
    as the title says, the car physics are really quite terrible.
    yeah, I hope there are some improvements for vehicles soon, although with a lot of tweaking you can get cars working sort of ok.

    i recently played with the 'advanced' ahem.. vehicle in 4.5 preview and was kind of expecting some improvement on the normal one.
    sadly, its even worse, sure the suspension looks visually different but the physics is almost non existent.
    I was expecting more as well

    also why does the car raise up as it gets going faster?
    its a known bug, ori said they were working on it, you can read more about it in one of my old threads https://forums.unrealengine.com/show...vehicle-issues

    has anybody found the cause of the mystery self up-righting?
    still a mystery for me

    i have started making my own vehicle using a physics asset with constraints but i cant get the wheels to spin any faster than about 10 mph.
    I haven't heard of that one before, what exactly do you mean, do you mean the wheels look like they are going 10 MPH but the car is going faster.

    are there any planned improvements or anything?
    I haven't heard anything other then whats in that old thread, hopefully someone will come in with more info

    Comment


      #3
      "I haven't heard of that one before, what exactly do you mean, do you mean the wheels look like they are going 10 MPH but the car is going faster."

      i made a pawn and added a physics asset of a car, the asset has physics and collision for the body and wheels.
      suspension is using a soft Z limit (whatever its called) constraint.
      im rotating the wheels by Add Torque to the wheel bones. havnt sorted anything about the steering yet.
      unfortunately there seems to be a maximum force, at least with blueprints, that makes the wheel spin relatively slowly, only pushing the car to about 10 mph.
      i could add force to the car body to make it go faster but that would be defeating the point.

      looking at the advanced car, all the 'physics' is done with animation, the body pitch/roll and the suspension, might be the most optimized way to do it but it makes for an unrealistic and oddly behaving car.
      Last edited by tegleg; 10-08-2014, 12:48 PM.
      tegleg.co.uk - indie electronic music label
      Android + HTML5 WIP Physics Game
      PC Games - Android Apps

      Comment


        #4
        Not exactly physics but when using automatic gearing it takes forever for vehicles to downshift even when at low RPM. In terms of the vehicle actor, braking shouldn't be negative throttle and should have a separate value since left-foot braking is a thing.

        Comment


          #5
          Youtube videos of UE4 vehicle setup

          Have you checked out the videos on Youtube? There are tutorials as well as demonstrations shared by others in the community.


          Others' results:
          http://www.youtube.com/watch?v=ES9hm3DI1qc
          http://www.youtube.com/watch?v=60o8tXgo_K8



          Tuning and setup videos:
          http://www.youtube.com/watch?v=9ariPx6M33o
          http://www.youtube.com/watch?v=dffa5u44nGw
          http://www.youtube.com/watch?v=6vFZ9alQKqI

          Comment


            #6
            yes i have seen the setup videos, thanks. i was half expecting one of those to be mine tbh lol.

            i think the problem is that the physics (suspension ect) are animation based, coupled with the strange 'wheels kind of suck to the floor' effect, makes the car behave odd in extreme situations.
            trundling around gently going over bumps and what not is fine, but just try a jump or a crash and the problem is instantly apparent.

            currently in the process of back engineering the whole thing to either fix epics code or create my own using what i learn.
            tegleg.co.uk - indie electronic music label
            Android + HTML5 WIP Physics Game
            PC Games - Android Apps

            Comment


              #7
              Originally posted by tegleg View Post
              i think the problem is that the physics (suspension ect) are animation based
              How exactly do you mean? I thought only wheel rotations were animation based.

              Here is my vehicle, btw. It isn't the latest form but it is good enough to show the car's behavior: http://www.youtube.com/watch?v=qauaFPYJBQw

              It also leans to the side as expected when you bump into the car in first person character, and suspensions work when i drop a weight on top of the car. I'm not an expert on this(smokey knows ) but i havent noticed anything absurd so far(other than the rear-raising and up-righting you mentioned.) Also i havent worked on an off-road car so maybe my expectations on suspensions are lower than yours.

              Btw, I havent tried 4.5 preview yet. Were you able to find out where suspension force offset setting has gone?
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                #8
                More about PhysX vehicles

                Originally posted by tegleg View Post
                yes i have seen the setup videos, thanks. i was half expecting one of those to be mine tbh lol.

                i think the problem is that the physics (suspension ect) are animation based, coupled with the strange 'wheels kind of suck to the floor' effect, makes the car behave odd in extreme situations.
                trundling around gently going over bumps and what not is fine, but just try a jump or a crash and the problem is instantly apparent.

                currently in the process of back engineering the whole thing to either fix epics code or create my own using what i learn.

                I don't know what you mean that the physics is 'animation based'. As I understand it, although the visual appearance of the vehicle is provided by a skeletal mesh, the underlying simulation is a raycast/sweep vehicle with a fairly rigorous simulation for tires, suspension, drivetrain, etc. You can read about the underlying PhysX simulation by downloading the User Guide for the PhysX SDK here.
                Last edited by Mike.Skolones; 10-10-2014, 05:37 PM.

                Comment


                  #9
                  wow thats a big post

                  whatever, the car physics is ****.
                  when they added the cars to rocket i thought it must be a ruff draft and they would get round to implementing it properly at some point.
                  now i see that they actually intended it to work this way im seriously contemplating if its worth adding a different physics engine entirely...

                  it cant be just me and smokey13 that see it?
                  do the cars seem just fine to everybody else?

                  maybe i have played too many car games and kind of want the next generation to be a step up, rather than a step back.
                  Last edited by tegleg; 10-10-2014, 04:36 PM.
                  tegleg.co.uk - indie electronic music label
                  Android + HTML5 WIP Physics Game
                  PC Games - Android Apps

                  Comment


                    #10
                    A different physics engine entirely? You are so frustrated by the UE4 integration of PhysX vehicles, that you are willing to rip out PhysX and replace it with Bullet, or Havok, or Newton, or something like that? Seems like a lot of work. There is certainly more to be done to make the vehicles easy to tune, or to support specialized vehicles like tanks with treads, but the integration and the underlying simulation should be flexible enough to do most any sort of car.

                    Originally posted by tegleg View Post
                    wow thats a big post

                    whatever, the car physics is ****.
                    when they added the cars to rocket i thought it must be a ruff draft and they would get round to implementing it properly at some point.
                    now i see that they actually intended it to work this way im seriously contemplating if its worth adding a different physics engine entirely...

                    it cant be just me and smokey13 that see it?
                    do the cars seem just fine to everybody else?

                    Comment


                      #11
                      Jacky wrote:
                      -->Here is my vehicle, btw. It isn't the latest form but it is good enough to show the car's behavior: http://www.youtube.com/watch?v=qauaFPYJBQw
                      Hey, that Challenger looks great! How many hours did you spend tuning it?

                      "Also i havent worked on an off-road car so maybe my expectations on suspensions are lower than yours."
                      In my opinion, it's easier to set up a decent off-road car than it is to set up a road car. Bigger suspension movements, and the tire model isn't as stiff and sticky, so it's more forgiving.

                      -->the rear-raising and up-righting you mentioned.

                      We're trying to reproduce this and fix it. I wasn't aware of the problem until now.

                      Cheers,
                      Mike

                      Comment


                        #12
                        Originally posted by Mike.Skolones View Post
                        Hey, that Challenger looks great! How many hours did you spend tuning it?

                        "Also i havent worked on an off-road car so maybe my expectations on suspensions are lower than yours."
                        In my opinion, it's easier to set up a decent off-road car than it is to set up a road car. Bigger suspension movements, and the tire model isn't as stiff and sticky, so it's more forgiving.

                        -->the rear-raising and up-righting you mentioned.

                        We're trying to reproduce this and fix it. I wasn't aware of the problem until now.

                        Cheers,
                        Mike
                        Thanks, Mike!

                        It took quite some time to tune it up since it was the first time i ever tried to get a vehicle going in Unreal(never tried it with UDK either) and i was confused with suspension force offset value but smokey13 helped me out with it. Also not having any experience didnt help with that rear-rising behaviour...i wasted some time tweaking the suspensions wondering if i was doing something wrong. But it is good to hear that you are aware of it now!

                        I still need to work on transmission values a little but it's not a big deal since suspensions, steering and extras are all working as i want now.
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                          #13
                          Originally posted by Mike.Skolones View Post
                          -->the rear-raising and up-righting you mentioned.

                          We're trying to reproduce this and fix it. I wasn't aware of the problem until now.
                          Mike
                          thanks mike, glad to see people are listening.

                          the engine and transmission and in essence the suspension is spot on, its the physical behavior of the car itself that seems somewhat open for ridicule.
                          integrating another physics engine is likely beyond me right now. Havoc, now theres a good physics engine, shame Project Anarchy is not more like UE4 or thats where i would be.

                          heres a little vid demonstrating what im getting at. its the advanced car template unaltered.
                          go have a look at the super-realism people are getting from the visual side of cars in ue4, shaders ect, then as you are watching this video, imagine a real life car behaving anything like this
                          tegleg.co.uk - indie electronic music label
                          Android + HTML5 WIP Physics Game
                          PC Games - Android Apps

                          Comment


                            #14
                            Originally posted by tegleg View Post
                            thanks mike, glad to see people are listening.

                            the engine and transmission and in essence the suspension is spot on, its the physical behavior of the car itself that seems somewhat open for ridicule.
                            integrating another physics engine is likely beyond me right now. Havoc, now theres a good physics engine, shame Project Anarchy is not more like UE4 or thats where i would be.

                            heres a little vid demonstrating what im getting at. its the advanced car template unaltered.
                            go have a look at the super-realism people are getting from the visual side of cars in ue4, shaders ect, then as you are watching this video, imagine a real life car behaving anything like this
                            Hey, that is quite strange! I haven't really played with the vehicles in a few months, when we worked out a bunch of bugs in the integration code, and a few in the underlying simulation. But I spent a lot of time tuning buggies and running off-road courses, and I didn't see anything like that. Clearly what you are seeing is not right, it's just a mystery as to why it is showing up. Does the car raise up if you zero the friction on the tires, or in zero gravity with the car in the air, and just spin the tires freely?

                            Comment


                              #15
                              I am seeing exactly this behaviour too (4.5 Preview download from the launcher)

                              Comment

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