[SOLVED] Strange slipstream effect when a car is FOLLOWING me

Discussion in 'Technical & Support' started by Eric Moinet, Jul 18, 2017.

  1. Eric Moinet

    Eric Moinet Registered

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    Hi all,

    This is a weird issue I'm experiencing on both rFactor 1 & 2 from the day I started to play these sims :

    When someone is behind me and closing on me I have a strange effect added to my car, like if the car behind me was "pushing" me even though the car is, say, 50 meters/yards behind me. This results at best in a sudden massive understeering of my car, or shaken all over the place and hard to handle (this is usually the way I know a car is closing on me), or in the worst case spinning.
    When I drive in a packed field with a car right behind me I usually don't experience that behaviour, like if a car being in my slipstream zone couldn't affect me.

    Okay, so as a picture is worth a thousand words, this is what happens to me, sort of :
    [​IMG]
    The "bubbles" around the cars are their "slipstream zones". I know/guess it's not like that for real but you can better understand that way the issue I have.

    It happens online and offline. It *might* be worst with AI than online.

    Config :
    AMD Phenom II 965 x4
    8GB RAM
    Switched from a Logitech G25 to a Thrustmaster T300RS, still the same
    Switched from a ATI radeon hd 6570 1GB vRAM to a AMD radeon rx 550 2GB vRAM, still no joy
    Video output on TV screen 42" 60Hz (vSync or not, no difference, but a bunch more fps without)
    Dx9 (Dx11 crashes rF2 for me BTW)
    (Changing steering wheel and graphic card wasn't related to the issue, but you can rule them out as a possible cause of it I believe)

    Had anybody experienced the same problem ? Could it be related with AMD not copping correctly with multithread inputs ? Does someone know how to fix it ?

    Any idea, clue, input, solution is welcome and much appreciated.
     
  2. peterchen

    peterchen Registered

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    This effect is burried deep in the physics file of the car. Ever wondered what it should be good for.
    But to be honest: I´ve never experienced this and in no way that massive that car is unstable or near spinning!
    Maybe your installation is screwed up somehow?
    However, if everything is good with your program and you still experience it, there is nothing you can do about it.
     
  3. stonec

    stonec Member

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    No I don't think it has anything to do with your hardware. In a mod you can basically adjust how big the "wake" of the dirty air is, and if you adjust this wrong, chances are your own car will be affected by this dirty air effect, which normally should only be in effect behind your own car. You didn't specify which car you drive, but I assume it's a mod that hasn't been built that well.
     
  4. Eric Moinet

    Eric Moinet Registered

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    Thanks guys, good to know it's a known bug but that doesn't help me a lot :cool:

    @stonec : short answer, every mod, every car, every track (more or less). I tend to better cope with it now in rF1 with better tyre and suspension settings, but I'm struggling with every new car I drive and with rF2 as I quite don't understand the new tyre model.
    Also, I'd like to hear more about how to adjust the "wake" of the dirty air you're talking about.
     
  5. davehenrie

    davehenrie Registered

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    adjusting the wake requires editing files that sometimes are locked up so we can't get at them. Use the mas editor and see if you can open up a car file and look for the hdc file. This is just the very teeny tiny tip of modding. Realize that any changes you make will prevent you from joining an online race.
     
  6. CamiloNino

    CamiloNino Registered

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    I have never experienced anything like that. And I don't think something so massive and wrong would have slipped as an undetected bug in the game.
     
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  7. Lazza

    Lazza Registered

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    Never had anything like this in either rF1 or rF2. And they don't tend to share the same issues (rF2 I'd be questioning physics staying in realtime with other cars around causing more load, but not rF1 -- as an example). I would check data (telemetry etc) to make sure you're not just missing brake markers or trying to carry more speed when you get someone chasing you (this might not be the case at all, but I don't know where your driving is so I can't really be sure).
     
  8. Eric Moinet

    Eric Moinet Registered

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    Hi DH :) Thanks for your input. Obviously I can't do that as I want to play online but thanks anyway.

    @Lazza : my driving skills are good enough, thank you :D After 3 years or so of weekly racing I've already checked that and definitively ruled it out. But to go your way it may more have to do with my poor ability to draw a correct setup for my cars (as I don't feel that effect, or less, when I succeed to put enough grip on the rear end). Anyway, as far as I understand it, even a poorly done setup shouldn't make me spin if someone follows me.:confused:

    @CamiloNino : okay, I admit that 'bug' is not the right word to use and I should have say 'effect'. Can you go back to OP and give me some help ? The fact that you (and others, not specifically you) never experienced it doesn't mean I don't have it and there's no need to fix it.

    I understand it is not a common issue and that mostly nobody got it, but it strongly impedes my driving experience, puts off all the joy you can have when racing, and this is very frustrating.

    So any idea, any help to solve this issue is more than appreciated. :)
     
  9. MarcG

    MarcG Member

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    I think a Video (if possible) might be able to aid us in helping you find a solution, as in all my years of RF1 & RF2 I've never seen anyone mention this effect causing such poor behaviour in "every mod, every car, every track (more or less)". To me it sounds like a problem with Braking, are your pedals calibrated correctly? Are you sure you're not locking up when turning in?
     
  10. Postipate

    Postipate Registered

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    Make video of this with pedal inputs and from lap without somebody following you.
     
  11. Nitrometh

    Nitrometh Registered

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    I saw some similar behavior on tv during Nascar at a speedway. The car infront loosed control because of the car behind it. They said the car behind pushed a lot of air under the rear of the car. So the rear end got light and there was less tyre grip.
     
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  12. Eric Moinet

    Eric Moinet Registered

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    A video will take a bit of time, but I'll do one if needed.
    But I don't *think* it's a braking issue : Thrustmaster 3PA Add-on with conical rubber brake mod on. And it also happens when accelerating.
    And it's not a driver's issue as well :rolleyes: I can fight with my opponents without problems when I can lessen the effect with a good setup, as you can see there (I'm in the white car. Mind you, how many braking point did we have from Mulsannes to Porsche curve ? And not an issue.)
    [​IMG]
    Okay it doesn't show how the effect happens it may explain why I believe it is a kind of inverted "dirty air effect" (to quote Stonec) rather than a driving behaviour or peripheral calibration (but can't rule it out completely)
     
  13. Jego

    Jego Registered

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    This can be fairly easily reproduced and checked with telemetry.
    Get someone onto teamspeak and a server with you and do a test.
    The telemetry will provide the data to check this.
     
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  14. Postipate

    Postipate Registered

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    Yeah even better idea!
     
  15. Eric Moinet

    Eric Moinet Registered

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    Yeah, good idea indeed. Will do it tonight and report later. Thank you.
     
  16. SPASKIS

    SPASKIS Registered

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    If you could upload some telemetry files with you driving alone and other files with you driving with the AI where the effect occurs it would clarify if there is such a significant difference as you claim.

    I will be sincere. My opinion is that you are doing something different when the AI is around. If you want people to take this issue seriously, provide some data. I trend to disbelieve in other people's feelings
     
  17. CamiloNino

    CamiloNino Registered

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    How is performance on your PC in terms of FPS?
    Do you run with virtual mirrors?

    This is my guess at what might be happening:

    Your PC specs are not very good to be honest (CPU and GPU wise), so I would guess you are probably running with very low FPS and some input lag, and considering you use a TV, which normally adds loads of input lag my guess is that your problem comes to even worse input lag when you have another car in the mirrors. You probably don't notice the difference when driving in a packed field since you will have constantly low FPS all the time in that case..

    Maybe try switching to a PC monitor, lower graphical settings to a minimum and deactivate mirrors, and see if you feel this effect again.
     
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  18. Eric Moinet

    Eric Moinet Registered

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    Thanks CamiloNino for your input. I like your idea about the mirrors (less the one about TV screen :D ) and will test it.
    For FPS I have between 60 and 200 usually.

    ===========================

    Edit :
    So, we can rule out the mirrors :cool:
    I'll test this week-end with an other screen either to rule that out too or confirm it is the culprit.

    On another note, I made a race with telemetry activated with Flat6 at Norisring.
    Maybe not the best conditions (bumpy track, poorly done setup) but we have the perfect example of what happens :

    8 Lap race, 9 cars on track, real humans not AIs
    Starting from last to have nobody behind me for some laps (it didn't last long, two or three guys ran out or spun in first lap)
    A couple of laps fighting with a guy, then I passed him at the first corner (the spin) making the move stick.
    And then I've lost the car at next turn (the S entry) when braking on a bump and spun : this only happened, in all the practice sessions and races we did, when someone was following me.
    Next of the race, last again and not a single issue, and closing on the guys ahead of me.

    For what it's worth, on such a track I stay focused on the next turn and don't look in the mirrors so I don't know if there is someone behind me. Every time I've lost the car 'for no reason' in the practice sessions there was someone behind me. I don't say I'm a perfect driver but usually i know when I make a mistake and take it for what it is.

    I didn't check fps all around the track but it was 108 fps in the straight line when passing the pit buildings.

    You can find the file here : http://www.mediafire.com/file/mhkacq0p3f5i4ob/LOG.zip

    The spin is lap 4 or 5
    I can't read those files so any help is welcome and much appreciated.

    Sorry, it wasn't supposed to be such a long post.
     
    Last edited: Jul 21, 2017
  19. SPASKIS

    SPASKIS Registered

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    Don't worry for the length of the post. It is much better the excess of information than the lack of it.

    I also agree Norisring is not the best track to check for a braking issue due its bumpiness which makes it difficult to replicate an equivalente situation only changing one or two variables every time.

    There is an option to resume from replay that could be useful for this purposes to get a consistent starting point with and without chasers. You would need to use AI as opponents, of course.

    In any case, your effort deserves taking a look and so will I do when I can. If I understood correctly there problem occurs in the S turn in lap 4 or 5 which was the only one where you had opponents. The rest went fine. Is it OK?
     
  20. Lazza

    Lazza Registered

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    Overlaying the traces (using data offset so the GPS positions are very close) shows very similar inputs and data. The only thing I'm noticing is the lap you spun (lap 3 in motec, because the first lap is always 'out') you were further to the left as you continued braking. All the other laps were very similar line, except for one lap when you were well to the right. I wonder if you left the track a little before your spin?
     

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