It's about the TIRES, stupid!

Discussion in 'General Discussion' started by Guy Moulton, Jul 9, 2013.

  1. Max Angelo

    Max Angelo Registered

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    Yes, indeed, and the tire model i guess is the "CPU cycles eater" which makes a so big difference. :)
     
  2. pleclair

    pleclair Registered

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    Yes it is there :) Been there for as long as I remember tire deforming themselves in LFS.

    Just double checked, and it still there... My ffb wasn't set properly, just installed the game and run a practice session, and even tho my wheel wasn't shaking, it could be felt very well while braking tho, with wheels locking on the flat spots...

    You can press f9 and see the tire stats, and you will even see the temperature all around the tire, so when you move on to the flat spot, you see the higher temperature of the spot :)

    LFS is a lot more complex than people think it is :) It's still a great sim today :) If tracks had more bumps and unevenness, it would be pretty good.
     
    Last edited by a moderator: Jul 9, 2013
  3. Spinelli

    Spinelli Banned

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    LFS has visual tyre deformation, yes. LFS has the ability to lock your brakes (what sim doesn't), yes. BUT, does it actually model flatspotting? The only sim I noticed this on back then was NKPro, I'm not so sure LFS had/has it.
     
  4. Guy Moulton

    Guy Moulton Registered

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    Someone told me that iRacing has flatspotting- but never drove it myself.

    If you want to geek out on this, load up a replay or better yet, watch a live race of the WCR60's mod. Pay particular attention to the tires. It is mesmerizing to see them oscillate over bumps, see the sidewall deflection and see the bottom of the tire flatten out on the road.
     
  5. Minibull

    Minibull Member

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    I remember LFS has some tyre deformation and there is flatspotting, but it wasn't physically modeled when I was playing it. Whether their physical tyre model impacts the FFB and what you are feeling, i dunno. You could see the flat spot on the tyre temp monitor as a hotspot that would appear, but there wasn't any effect on the FFB. That was a couple of years ago though, so I dunno if they have changed things.
     
  6. Spinelli

    Spinelli Banned

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    That section of the tyre heating up doesn't necessarily mean it's modeling a flatspot, but just could be different areas of the tyres heating. A flatspot would be the tyre physically flattening out (regardless of wether it's graphically represented or not), and then it's easier and easier to lock up on this flatspotted section of tyre as you brake near the limits, making the flatspot worse, which in turn makes it even easier to lock up at that part of the tyre, and so on, like a snowball effect. I'm sure you know what flatspotting is, I don't mean to imply that you don't :)

    Im really trying to remember flatspots in LFS, but I can't. I could feel when I badly locked the brakes, and it also made a hot area at that section of the tyre, but I think the game continued to model a round tyre in it's physics, rather than a ahhemm mostly round tyre lol
     
    Last edited by a moderator: Jul 10, 2013
  7. Lazza

    Lazza Registered

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    To relate all this back to the OP, the flatspots and their effect on FFB and grip aren't actually all that complex. You could fake those effects well enough to trick pretty much anyone that they're being modeled correctly (maybe you could try to set up a test to weed out the fakes, but again, you could target such tests with your fakery (!)). Whether a particular sim 'includes' flatspots, and the various knock-on effects, doesn't mean it does the same stuff rF2 does.

    It seems likely rF2 has taken the entire tyre model to another level, but how far in front of other games' models it is, and whether any of us can ultimately actually tell the difference (and whether the average modder has enough knowledge and knowhow to build a correctly operating tyre, for that matter), we may never know. Of course I doubt that'll stop people having and sharing their opinions.
     
  8. sFactor

    sFactor Registered

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    I am in the camp that this day and age we should be able to have both.

    I mean, I don't even think you can buy a single core cpu anymore and the core count and ability to multi-process threads is only going to keep getting better.

    I am not expert graphics or vehicle physics coder so I really can't even imagine what these guys are up against here.

    The thing that really sticks in my craw is the whole DX9 situation. Video card/GPU manufacturers are focused on optimizing cards for DX11 and beyond. Just look at the bench mark of a 5870 (still a strong card today) vs the 7850, a lower end card by today's standards, In DX9 games, the 5870 can actually outperform the newer 7850 and maybe keep up with a 7870 in rare cases. Look at the DX11 results from a game like BF3. The 7850 trounces the 5870.

    How long are the GPU manufacturers even going to support DX9 let alone optimize next gen cards for it. Again, my knowledge of the internal workings of Direct X are minimal, so maybe someone can enlighten me as to why DX9 in preferred by ISI?

    Riff
     
  9. zim2323

    zim2323 Registered

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    That does nothing to show how much is actually being used by the tire itself. All of this is just here-say. Show me concrete evidence of exactly what % of that purple line is tire physics eating CPU and then we'll start talking.
     
  10. Guy Moulton

    Guy Moulton Registered

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    hear hear
     
  11. o0thx11380o

    o0thx11380o Registered

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    Its most likely preferred because rfactor 2 is basically an enhanced rfactor 1 unfortunately
     
  12. Kknorpp001

    Kknorpp001 Banned

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  13. pleclair

    pleclair Registered

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    I'm not sure if it is modeled visually, I forgot the camera controls and couldn't find a good view of the tires, but it is there nonetheless..
     
  14. pleclair

    pleclair Registered

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    Like I said, I dunno if visually you can see it, but it's there... I haven't played long enough to really ruin the tires, but a quick ride in the formula v8 quickly showed me it is there.

    I came up the long straight at blackwood, and jammed the brakes, and next turn, the wheel locked at the flat spot, like it should... but that time, I didnt slammed the brake, but progressively until lock... so it found the flatspot. I was playing with only the wheels showing, so I could notice the wheel locking at the flatspot by the way it slowed and locked. And I could feel it as well in the ffb.

    But that was about my testing, cause I remember when that feature came along, I was playing regularly that game, and people where complaining big time... also appeared at the same time at clutch wear out... another thing people complained.

    Try it out, you'll see for yourself :)
     
  15. Max Angelo

    Max Angelo Registered

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    My post was a gross statement, pointing to the fact that TGM, by itself, is a complex technology which requires a lot of CPU power.

    If you want an "accurate" measurament (the brackets because still is just a bar) you can edit the plr line

    Old Tire Model="1" // Only works in Dev builds, drive with old tire model

    then open Dev Mode and press the key combo ALT+T (activating the old model).

    The accurate results, in my "minimum requirement CPU" machine, are shown in the attached shots.

    GRAB_002 is with the full AI physics, GRAB_000 is with "human physics" but tbc, GRAB_001 is with human physics and tgm.

    As you can see, the tgm by itself uses by far the biggest percent of CPU load of the "physical thread"
     

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  16. zim2323

    zim2323 Registered

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    That's what I was looking for! Thanks!
     
  17. Max Angelo

    Max Angelo Registered

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    Actually i forgot to remove the AI in Dev Mode, but running alone the results are about the same
     

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  18. PMC

    PMC Registered

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    I thought I read some where tyres use 50kbs per tyre
     
  19. Minibull

    Minibull Member

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    I remember reading posts from one of the ISI devs in regards to wonky tyre deformation in replays. You know how they spaz out a bit, and wobble around, He said something like to record the tyre data that is going on, we would see replay files going upwards of 50gb. Something to that effect anyway. And seeing the posts from Max above gives an ingame view of it too I guess.
     
  20. Spinelli

    Spinelli Banned

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    Is this physics model actually processing a tyre that's not round anymore? Or is it just saying "on this section of the tyre, make the grip less".?
     

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