Does rF2 implement chassis-flex or semi chassis-flex?

Discussion in 'General Discussion' started by Joe, Sep 2, 2015.

  1. DurgeDriven

    DurgeDriven Banned

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    At Malmedy chicane I can hear the wooden dash creaking, even in a F3. hehehe

    I guess you call that body flex.

    Like F1 Spark is 400bhp bolted to a bath tub its gotta flex somehow. hehehe

    David says Go Karts, I say look at NHRA Pro Stock you wanna see chassis flex. hehehe

    Hey Spin....how is that v1.38 Aussie V8 ! ....... on special till Sunday too.
     
  2. Joe

    Joe Registered

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    This is so true.

    Some more life footage of suspension movements:



    One thing I do not understand is the so-called "laser scanned tracks". I guess I just couldn't trust them in terms of track surface bumps, etc.
    This turns out to be pretty reward thread. We may use as benchmark to against/help rF2, AC or other sims future builds in terms of suspension/track work.
     
    Last edited by a moderator: Sep 4, 2015
  3. Euskotracks

    Euskotracks Registered

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    All cars need to have proper chassis flexibility simulated in order to account for realistic tire loads. Since karts have no suspension, it is fundamental in those or the modelling error would be huge. The stiffer the suspension the more important role chassis flex plays.

    Enviado desde mi SM-G130HN mediante Tapatalk
     
  4. David Wright

    David Wright Registered

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    The Lotus 98T is not the right car to compare suspension movement with a Brabham BT20 or a Lotus 49. By 1986 F1 suspension was much much stiffer than it was back in the 60s.
     
  5. Spinelli

    Spinelli Banned

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    If you guys want to talk about graphical physics movement rather than physics engine physics then I feel RF2 is still lacking. Cars look amazingly static especially compared to Live For Speed or even iRacing let alone real-life.

    I'm guessing something in the engine just doesn't translate well into visual physics, maybe it needs a deep, ground-up overhaul in that standpoint, I don't know but things just don't look realistic or correct from a visual point of view.

    Durge, the Aussie V8s are great fun :). Near/at/over the limit it is still just like every other single car in a pre-RF2 ISI engine from the past 15 years as the "core" physics engine hasn't changed but other than that I think Reiza, as usual, have done a tremendous job of extracting the most they can out of the physics engine (RF1) at their disposal.
     
  6. Marc Collins

    Marc Collins Registered

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    Yes, but there are cars like karts and the older historic vehicles where it will be possible to "feel" the difference through decent FFB hardware. Just don't think you'll be able to tell the difference between a 2006 F1 car and a 2008 one. Chassis flex would be very evident in most of the 1960's GT cars (the GTL/HistoriX stuff). Too bad we're not going to see those in rF2 anytime soon.
     
  7. DurgeDriven

    DurgeDriven Banned

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    Muscle Car era with full big blocks, lifting one wheel, popping glovebox lids, twisting chassis rails, etc.

    Mixture of chassis and body flex, basic 4 point rollcage stiffness up a streetcar

    Flex could be put to good use in a Drag Mod :)
     
  8. David Wright

    David Wright Registered

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    The proof of the pudding is in the eating. I suggest someone edits the chassis stiffness of the BT20 - say increasing it by a factor of 10 and sees what difference there is. The BT20 was something of a paradox. Brabhams of this period were widely considered to be the best handling cars, but their space-frame chassis were typically half as stiff as their monocoque rivals.
     
  9. GaetanL

    GaetanL Registered

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  10. unknwn

    unknwn Registered

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    I think chassis flex in rF2 is represented visually by adding additional movement of the suspension/wheels. You can visually see cart wheels jumping like they would have suspension instead of actually flexing chassis. Is that correct?
     
  11. GaetanL

    GaetanL Registered

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    Url is obsolete :(

    http://projectd-team.xooit.com/t23-R-Factor-2.htm?start=388

    Look at the graphical bug on the second one, I don't think it's due to suspension ;)
     
  12. unknwn

    unknwn Registered

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    @GaetanL
    Last time I drove rf2 carts, there was "suspension" movement (looking at the wheels and the spot where wheels are bolted to the chassis), even thought it doesn't have suspension. Hence my assumption;)
     
  13. Joe

    Joe Registered

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    I agree. To be fair, we shall do "apple-to-apple" comparison as much as possible.
    Last night I made a video on rF2 Brabham at same track Monza as I did for AC. I did quick run and sorry I did not even use H-shifter. Instead I used auto clutch. Slow, anyhow, just make a point here though. Here are, BT20 at Monza, the suspension movements are huge, as you can see the drop/rebound while braking and turning, etc, :



    Now, lets look at the AC car at same track again. We noticed how little movement of suspension. As DurgeDriven initially pointed out there is not even drop while braking or corning:



    By comparison between two in above two videos, it is obvious that suspension movement between two is quite different. Well, there are different cars. We actually are not sure if such diff is indeed due to different cars or different sim modeling.
    Lets take a look at real life suspension movements of some classic cars again:





    It seems conclusive from above videos that rF2 suspension is more realistic than AC. Well, since the real life cars in the videos were not Lotus 49 we just cannot be 100% sure to conclude such.

    Again, best way to objectively conclude this is to study telemetry data between sim and real cars. One guy, DrRacing, actually did just like that on rFactor (rF1). He studied telemetry data with same F3 cars and same track to compare rF1 sim car with real car telemetry data (same formula 3 cars with very similar tunes). The results showed the rF1 suspension actually remarkably accurate. Here are the data:

    [​IMG]


    [​IMG]

    Both driving are pretty close, so pretty much "apple-to-apple", such as throttle, steering, and RPM, etc:


    [​IMG]

    [​IMG]

    [​IMG]


    that leads me believe the rF2 suspension could be very accurate.
     
    Last edited by a moderator: Sep 9, 2015
  14. GaetanL

    GaetanL Registered

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    Yes, suspension moves too (it's working fine :D),but (and it's a little hard to see that on pictures) the 'front bar' is not parallel with the rear one and this can only happen with chassis flex. If there aren't visual chassis flex (only suspension move) the rear and front must stay parallel (and there will no bug exhaust pipe). Try it when you turn around in replay it's more flagrant ;)
     
    Last edited by a moderator: Sep 5, 2015
  15. Spinelli

    Spinelli Banned

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    Everything looks so static in-game. It's like the fidelity or just the all-together connection of physics to graphics has been cut by 10. Everything looks weird and jelly like; it doesn't look like physical objects with mass undergoing movements and jolts - looks so digital and fake.
     
  16. Joe

    Joe Registered

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    although you see the whole body of the car, but the camera actually is mounted on the car (chassis). so it represents a relative movement of suspension referenced to the chassis only. Of course, no chassis vibration is assumed here. Hence all thing is static. This is not a case like as if your helmet camera sees (your body is flex).
    Please we are talking "visual physics" here for suspension, not a graphic quality,visual reality, or in that nature.
     
  17. WiZPER

    WiZPER Registered

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    As the topic has moved to suspension movements (and since flex is not visible as we've concluded), I think that this looks fantastic and gives a good immersion of the weights being shifted - you can really sense how the suspension is fighting that heavy engine... :cool:

     
  18. Lazza

    Lazza Registered

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    Yes, but it's not really 'added' as such, like somewhere in the graphics code it says 'well we don't show the chassis flex graphically, so let's increase the suspension movement to compensate'. Not saying you were suggesting that, but someone reading what you've said might take it that way :)

    The chassis flexing will naturally offset the front and rear suspension positions somewhat, with further suspension movement on top of that. So what you see with the final positions reflects 'normal' suspension movement plus chassis flex, but without the chassis itself actually appearing to flex. When I first followed the chassis flex tutorial I checked it was all working by setting it very soft and then parking with one front wheel on a high kerb, and could see a marked difference in the angles of the front and rear suspensions as the other front tyre drooped down to touch the ground. Then I went back and tightened the chassis flex and repeated the test, and that other front tyre was sitting well up in the air... slightly lower than without chassis flex, but not much :)
     
  19. unknwn

    unknwn Registered

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    Someone driving carts in rF2 can it take it way by looking at the wheels movement because there is no visual chassis flex ;)

    On carts "invisible chassis flex" looks quite weird (wheel connections are clipping through chassis while flexing).
     
    Last edited by a moderator: Sep 6, 2015
  20. Nitrometh

    Nitrometh Registered

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