Return of the development blog, point-based accelerations for TGM (QSA) analysis

Discussion in 'General Discussion' started by F1 2004, Dec 26, 2017.

  1. F1 2004

    F1 2004 Registered

    Joined:
    Oct 28, 2010
    Messages:
    558
    Likes Received:
    128
  2. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,346
    Likes Received:
    6,572
    Nice!
     
  3. Alejandro1

    Alejandro1 Registered

    Joined:
    Aug 17, 2014
    Messages:
    75
    Likes Received:
    5
    To be sure: cars like F1 and Indy won't see much of an improvement for the time being. Is that correct?
     
  4. Prodigy

    Prodigy Registered

    Joined:
    Nov 2, 2012
    Messages:
    949
    Likes Received:
    64
    @Michael Borda
    So, is the Radical SR3 only car that got updated with new QSA model?
     
    patchedupdemon and LokiD like this.
  5. LokiD

    LokiD Registered

    Joined:
    May 3, 2017
    Messages:
    1,282
    Likes Received:
    1,216
    i wonder also, I'm totally confused now what cars are running the impoved model. i suppose the gt and the fe dlc?
     
  6. davehenrie

    davehenrie Registered

    Joined:
    Jul 6, 2016
    Messages:
    7,454
    Likes Received:
    4,369
    In addition to your cars listed, The non GT3 Radical, and the Honda Civic, as well, I would assume. Since both were mentioned either in the blog or the roadmap. Oh, and the Nissan GT500. Much different feel from it's original release.
     
  7. LokiD

    LokiD Registered

    Joined:
    May 3, 2017
    Messages:
    1,282
    Likes Received:
    1,216
    were assuming here though?
     
  8. SPASKIS

    SPASKIS Registered

    Joined:
    Sep 7, 2011
    Messages:
    3,155
    Likes Received:
    1,426
    I wonder what calculation of centrifugal forces in a quasistatic model meant.

    Centrifugal forces are related to a mass describing a nonlinear path and depend on the square of the speed and on the curvature of the described path. Quasistatic approach is used to determine the reaction of the tire under deformation. When doing the force and momentum balance equations for sure you need to account for centrifugal forces (when using local reference system) but those should be independent from the quasistatic approach itself. They just need to be added accordingly to their real path. For the nodes in the contact patch itself this centrifugal forces are actually zero since the trajectory they describe is not circular but linear with respect to the local coordinate system.
     
  9. Sebastien Sestacq

    Sebastien Sestacq Registered

    Joined:
    Jan 11, 2016
    Messages:
    851
    Likes Received:
    1,436
  10. Comante

    Comante Registered

    Joined:
    Nov 20, 2013
    Messages:
    1,694
    Likes Received:
    1,218
    I would say that your assumption is uncorrect, when a point hit the road surface, there is a sum of forces, and not a subtraction.
     
  11. SPASKIS

    SPASKIS Registered

    Joined:
    Sep 7, 2011
    Messages:
    3,155
    Likes Received:
    1,426
    What are you talking about?
     
  12. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,346
    Likes Received:
    6,572
    I think it's as simple as described - the data they had for tyre behaviour suggested what they were doing was close enough to be within margin of error, so no need to change it. The comparison shot indicated the old model would keep forces relatively high in the middle of the contact patch when the tyre was overloaded, so some sort of leftover of the centrifugal force was used through the contact patch and was enough to keep better (heavier) contact. Subsequent data showed this wasn't correct, so now the middle of the contact patch has less force, the contact patch elongates with more deflection. Or something.

    What I find more interesting is the whole catalyst for this - previous data (provided to ISI) was extrapolated and simplified, and that meant the model appeared to be good enough. One question often posed (ok, maybe not THAT often, but sometimes...) is why go to this tyre model that needs you to define the shape of the tyre and do all the lookup table calculations etc, when rF1 and derivatives use slip table data to determine behaviour - and often that data is easier to obtain in the first place, so it's easier to match. Input = output.

    Well here's an answer - even years of tyre data can be wrong. If your model gets very close to correct behaviour, and you get the construction close, the behaviour will be close. Using slip tables will only ever get as close as your data is, and can be tricked by erroneous data.
     
  13. SPASKIS

    SPASKIS Registered

    Joined:
    Sep 7, 2011
    Messages:
    3,155
    Likes Received:
    1,426
    Besides that, slip tables might be good enough for non powered tires under acceleration. With only two significant force components (normal and lateral) lookup tables are assumable but when you introduce the third component (longitudinal) it comes quite tricky since the number of combinations increase a lot. Significant longitudinal forces appear in all tires under braking and in powered tires under acceleration.
     
  14. Emery

    Emery Registered

    Joined:
    Oct 24, 2010
    Messages:
    3,035
    Likes Received:
    1,654
    Proper tire flex animation requires using the more complicated model. The simple model has no animation other than rotation or a fake animation.
     
  15. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,346
    Likes Received:
    6,572
    I don't think animation is a big factor here. If you're willing to keep going with a slip table system you can get it close enough with fake animation as you say. Certainly I don't think anyone will notice the difference by looking at it.
     
  16. LokiD

    LokiD Registered

    Joined:
    May 3, 2017
    Messages:
    1,282
    Likes Received:
    1,216
    would people agree to these cars being the only ones updated. Be nice if a dev could confirm what models have the brand new tyre model? @Marcel Offermans
     
  17. LokiD

    LokiD Registered

    Joined:
    May 3, 2017
    Messages:
    1,282
    Likes Received:
    1,216
    just seen this comment on steam



    Michael Borda 18 hours ago
    @opteron apologies for that. Bit of a mix up, we have this done internally, we just need to get this properly tested and released publicly.
    So far then, it would just appear to the the Formula E, GT3 pack (McLaren, Callaway, Radical RXC, Mercedes-AMG, Bentley) and Honda Civic BTCC.
     
    Prodigy likes this.

Share This Page