Physics/FFB rates upgrade?

Discussion in 'General Discussion' started by Stan, Mar 8, 2017.

  1. Marek Lesniak

    Marek Lesniak Car Team Staff Member

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    @Stan
    Yes, CPU impact will be higher and we have to remember, some users have their PCs spec'd at around our min. requirements. Higher rates would mean, more chance of getting out of real-time for them.

    @Ozzy
    I think it's at the base rate.
     
  2. Euskotracks

    Euskotracks Registered

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    In the same way as for FPS, FFB, Triple Screen, VR..., hardware makes the difference, providing a slight advantage to those that can afford thousands of € in simulation wrt to other people that have more simple racing hardware. That is how it goes but it should never be an excuse to refrain any improvement to be implemented into simulation.

    I guess the right wat to proceed in this case would be the following: (It really applies to any simulation parameter)
    1. Evaluation of the potential benefit: I understand that for S397 shouldn't be that difficult to change the value for internal testing. Changes in results should be measured in both quantitative (telemetry) and qualitative (feeling). The "testing bank" should be as simple as possible. Oval racing is a good scenario for some basic tests. If improvements can be measured there, those improvements could directly be extrapolated to any track.

    2. If after step 1, it is decided the benefits are worth, I would definitely go for this option. However, in order not harm performance for lower end Hardware users, the possibility to adjust this calculation frequency should be included.
     
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  3. 2ndLastJedi

    2ndLastJedi Registered

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    Even consoles are out performing some lower end hardware. I don't think a Sim should be held back because of that! Or maybe the Sims should go cross platform. lol
     
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  4. DaVeX

    DaVeX Registered

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    Reiza physics/ffb rates upgrade, was like night an day on my poor G27, I can feel the difference...so...why don't have it on rF2?
    If rF1 engine can support this why not the rF2 one?
    There are a lot of little things Reiza did for the rF1 engine which will work on rF2 one too, will be great to have the same features here soon or later...
     
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  5. patchedupdemon

    patchedupdemon Registered

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    The jump for rf2 to up its rates wouldn't be nearly as pronounced as it were in ams,because the rates are higher gear than they were originally in ams.

    Benefits get smaller as you Aproach a certain rate,I highly doubt we would notice a night and day difference even if we were to double the rates here
     
  6. stonec

    stonec Member

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    The tire model is the most critical part, and it already runs at 2400 Hz, to demand higher makes no sense IMO. Also for physics it might not be a good idea to offer different rates for different users. In F1 Challenge (yeah, the game that was released in 2003), there was a setting called "half rate". If you turned it off, presumably the calculations were done at double higher rate, but it cost 0.5 seconds per lap online on most mods, consistently. So using a higher rate of calculations was actually slowing down lap times in that instance.
     
  7. Lazza

    Lazza Registered

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    Did you read the thread, or just the first post? rF2 isn't rF1, so you can't expect the same modification to have the same effect.
     
  8. DaVeX

    DaVeX Registered

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    I know they aren't the same so I am asking if rF2 can suppot the option too or not and which will be the difference between the two...
    At the same time I was thinking of the great improvements Reiza did on the old version of the engine and asking if same work can be done for the new one used in rF2 or not due to differences between them...
    I don't care how can be done but how can we have the same results...
     
  9. Stan

    Stan Registered

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    @Marek Lesniak:
    rf2 base fan's (I'm in) love it because it is a pure simulation with no compromise, giving us the closest to what professional F1 teams can run in term of software.
    As you know, simulating car racing is very complicated, and if those teams invest that much in their sim department, we ("real sim" customers... rf2 customers, not the same market than simcade customers) don't expect having "serious simulation" without making few efforts on ours spec's...
    Anyway, thanks for your answer.
     
  10. Stan

    Stan Registered

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    @stonec: "The tire model is the most critical part, and it already runs at 2400 Hz, to demand higher makes no sense IMO"
    Totally agree on this, no need to upgrade the tire model refresh rate... but maybe upgrading the "overall base" a bit (400hz to 500hz) will let us benefit more of it!?!
     
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  11. Lazza

    Lazza Registered

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    @Stan So 2400 is enough for tyres, but 400 to 500 will make a difference to the base? Why not 3200 for the tyres?

    Numbers are just numbers, we can throw them around all day but without knowledge of the inner workings and the mathematics involved we can't realistically judge what would be beneficial.
     
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  12. jo_siffert

    jo_siffert Registered

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    Just to remeber: 1hz is 1 cycle per second - 2400hz is 2400 cycles per second -> every 0.42ms a new calculation sent to something. 500 hz is every 2ms -> sent to something. Are we really able to feel the difference?

    If i'm completely offtopic, its my first post here :)

    Greets
    Jo
     
  13. Stan

    Stan Registered

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    @jo_siffert: "If i'm completely offtopic, its my first post here", a bit, but welcome anyway... et "Vive la Suisse libre"!

    @Lazza: I think you misundertood what I wrote... 2400hz is already a very fast rate... so again, no need to upgrade it, but those 2400 are thrown to the software (not to us), right now we have the result of 2400/400, so 2400/500 will give us 25% more "overall" accuracy. Regarding the knowledge, "Numbers are just numbers", well and you probably know that sometimes they are usefull... thus, I am not judging, I am just asking...

    So guys, If we already know the good job that Studio-397 is doing for the graphics part, I would like to know what would/could be done to the physics? Sure it's already the best with all the features implemented by ISI (flex, cpm, etc...), but "maybe" it could be a bit more bettered (again)? Therefore, does S-397 have plans for upgrading/bettering the physics engine itself?
     
    Last edited: Mar 19, 2017
  14. DaVeX

    DaVeX Registered

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    yep, I was thinking this too and I donìt know if this is correct or not to suppose (please tell me if we are wrong) but thanks to you I don't need to use google translator to explain, lol
     
    Last edited: Mar 19, 2017
  15. Emery

    Emery Registered

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    I think most of us feel that there are other areas of rF2 that need improvement sooner than the physics rate. Maybe it only takes an update to a global variable for that to happen, but somehow I suspect there's more involved in order to keep the system synchronized.
     
  16. Stan

    Stan Registered

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    @Emery: "I think most of us feel that there are other areas of rF2 that need improvement sooner than the physics rate", so, what are the others physics upgrade that would/could be done later by S-397, that's my question?
     
    Last edited: Mar 19, 2017
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  17. Devin

    Devin Member

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    @DaVeX asked me to comment on this. So here I am.
    The way I've understood it, people either want FFB to run at 500Hz or even the whole physics core. I'll explain why both would not work:

    Assuming physics ran at 400Hz like it is suggested in some posts throughout several threads:
    Running FFB at 500 and physics at 400 would be like running a game on a 60Hz monitor that only outputs 50fps. It won't look as smooth anymore, you'd get tearing and overall it wouldn't make sense to run the monitor at 60Hz if you only get 50 different images per second anyway. So that part makes literally zero sense.

    For those who want physics to run at 500Hz instead of 400, here's a little tip: My old Intel Core i5 that I recently replaced already struggled to run rF2 at 400Hz for mods with high quality tyres. CPU load would shoot up to 100% and I'd rarely even drop out of realtime. Now imagine what wouldhappen if you had 25% extra load. Exactly, it'd be completely unplayable and half the people who own rF2 could no longer play it. And for what benefit? Almost none at all. I tell you, if S397 were to secretly raise the refresh rate to 500Hz not even a superrobot would notice an actual improvement. It is simply too fast for humans to pick up those changes. Is it worth eliminating a good majority of the playerbase for a change that could almost not be felt? If you ask me, absolutely not. I already had to get a new CPU and I don't wish anyone else the same fate.

    And for those who argue that you could just give us a setting to run at 400 or 500Hz, sure, but that'd make stuff more complicated once again. Not much more I guess, but still, it wouldn't quite work well either.

    Why other games can run at higher rates you ask? Let me explain: I've created a clone of the SNES game F-Zero once. Not much physics involved, not much CPU to be used. The game's physics core ran at up to 50000Hz. 50000!!! And you know why? There was nothing to be calculated, so why would it matter? Now games that are based on rF1 and it's tyre model don't have nearly as much to calculate, so I see why those could potentially run at 1000Hz even without major performance problems. Though the very undetailed physics negate that experience entirely. rF2 comes with a tyre model so detailed that the first build was almost unrunnable unless you had a new NASA-PC. They changed something in the second public build and made it sort of runnable and since then every build has made the code more efficient, but every new car has made the tyres more detailed in return. There is a reason why AI don't use the detailed tyre model either: Having just two cars use it would probably be too much for 99% of the playerbase's PCs. That's why AI use the old rF1 tyre model.


    However, this all only counts when you assume that physics actually runs at 400Hz. According to Marcel, tyre physics run at 2400Hz. So why doesn't FFB run at that you ask? Because most wheels can't handle it. Why can't they handle it? Because it's too fast even for high-end electronic equipment. And even if it was technically still possible, the wheels' drivers often simply don't support it. So how are you, the player, supposed to feel a difference? This counts for all sims.

    tl;dr it just doesn't make sense and even if it did, rest in peace all those CPUs out there.

    This post just covers every possibility. It is supposed to explain in detail what happens. I do not intend to say anything like "don't do it, it's crap". This is just supposed to be information for those who wonder what actually happens behind the scenes of racing sims.
     
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  18. DaVeX

    DaVeX Registered

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    Thanks mate, for a noob like me is very clear now.
     
  19. Stan

    Stan Registered

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    @Devin: Ok, thanks for your explanations, I understand and agree; but still I continue thinking that we could use 500hz for
    ffb and physics rates synced with not that much impact/cost for the average end-user.
    We are in 2017, I use an i7-920@3.6 (7/8 years old) and my purple bar never exceed the middle of the graph, so it should
    be able to deal with a 25% extra!
    After all, real life have 10^24hz refresh rate so... the more, the best... and the less "instant lag".
     
    Last edited: Mar 20, 2017
  20. stonec

    stonec Member

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    i7-920 @ 3.6 GHz still demolishes any AMD CPU in single-core performance (up until recently released Ryzen). The 10-20% of rigs that run AMD FX can barely play rF2 with many AI as it is, so a 400 to 500 Hz increase is huge for them, I'm afraid.

    Regarding the question what other physics upgrades I'd like to have before Hz is adjusted, here are some:

    - Make different materials (grass, sand) slow down tires realistically and without crazy overheating. TGM only responds to one material value as it is now, which is the grip coefficient.
    - Make temperature transfer from realroad to TGM and vice versa. Currently 0 and 50 degrees road temperature produce the same lap times and tire temp.
    - Add better model of standing water to support aquaplaning (current grip loss is using some basic approximated, linear function)
    - Add realistic drivetrain/transmission model with mechanical damage
    - Add support for hybrid engines (ERS/boost/harvesting)
    - Add support for moden differential with onboard adjustment
     
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