Dirt Racing Improvements

Discussion in 'General Discussion' started by ShawnB, Oct 6, 2010.

  1. TUNDRA_schumacher

    TUNDRA_schumacher Registered

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    Our lawnmower mod could do with some better dirt physics, plus I never did think the sprint cars felt quite right in rfactor.
    I think if rf2 can do dirt better, it will hold my interest longer than 1 did.
     
  2. Dalton Dietrich

    Dalton Dietrich Registered

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    TUNDRA:

    Try the BOZ Sprints Best there is.
     
  3. Major_Catastrophe

    Major_Catastrophe Registered

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    Tundra - you need to distinguish between what the modder is responsible for and what ISI is responsible for. Better dirt physics for the lawnmower mod is the responsibility of the modders, not ISI. Same goes for a lot of requests in this thread.

    @Dalton IYHO ;)
     
  4. TUNDRA_schumacher

    TUNDRA_schumacher Registered

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    Well mr know it all smarty pants, we did find limitations when making the mod. But since your unearthly powers of modding would make our work look like kindergarten coloring, perhaps you could help us with the RF2 version :rolleyes:
     
  5. Bill Malicoat

    Bill Malicoat Registered

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    A lot of mods are well done and I do not want this thread turning into an argument over who's stuff is the best or any thing like that. This is just a place that we can all make suggestions that we "think" we need to make rFactor better for dirt. Lets try to keep focused on useful information here, we can and maybe should start a thread in the rFactor 2005 forum with useful tips and ideas how to work with what we have so we can all improve on our mods.
     
  6. ShawnB

    ShawnB Registered

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    Bill couldn't have put that any better. If you guys want to start up a thread in the 2005 rFactor forum, I support that 100%. Also, I know a good bit when it comes to creating oval dirt physics for rFactor. I have created a few mods over the past 3-4 years, and would love to help others out with issues they may be having.

    I've helped many people out with designing mod physics, and even helped BOZ out a bit with some things. In return Bill has helped me out a lot, as he was good at putting technical terms into Layman's Terms for the everyday person to understand the technicality of rFactor Physics. With that, Bill has helped me a ton do some final tweaks on the OHM Big Block physics and get them driving pretty realistically in rFactor. So, I feel if anyone needs help, the rF 2005 forum is the place to ask away. It gives a lot of people the chance to chip in and help explain things, and even get help from ISI themselves.

    So lets get this thread back on track of rF2 Oval Dirt idea's and suggestions.

    Thanks
     
  7. Mitch Harris

    Mitch Harris Registered

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    Though its getting a bit tough now Shawn as everyone here has basically covered every main aspect ahah :).

    Also @TUNDRA_Shumacher arnt you the guys that were working on the 1965 USAC Midget mod? :).
     
  8. Major_Catastrophe

    Major_Catastrophe Registered

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    So Tundra ... spell out the limitations and lets get ISI to help us out with them. :) If they apply to the lawnmower mod, chances are they will have applications for all dirt mods.
     
  9. Major_Catastrophe

    Major_Catastrophe Registered

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    In addition to Mitch's comment, we aren't going to know what is required for rF2 if we don't understand what was lacking in rF1. Discussing rF1 dirt in this topic is entirely appropriate.
     
  10. Bill Malicoat

    Bill Malicoat Registered

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    Your right, that is what I meant in my post. The comments that say who or what is better is what I was getting at. The limitations should be brought up for sure. One limitation I would like to discuss is tire wear with dirt tracks. Currently I can not find a way to make a track with less traction on it have more tire wear like a real dirt track. The only exception to this is a dirt track that is "rubbered". I have tired about everything I can think of and no matter what a track with a higher TDF value makes the tires wear much faster. I would like to know if there is a way around this in RF1 and if not what can be done in the future to make this a possibility.

    Questions like this I think can be a huge benefit to the whole dirt community.

    Another thing that I have found in RF1 since you can not do a a solid front axle is a way to get the correct spring rates. A solid axle has a different bump rate then a roll rate at the wheel. A double wishbone does not, the only way I have found to make this correct is to measure the pick-up points on a real car and calculate the wheel rates in roll. Then once you know the difference in roll rate vs bump rate you can use negative sway bars to accomplish this. Then the issue is the distance the track width changes in the front of the car to simulate the roll center height of a solid axle with a panhard bar, this I just had to deal with because I could not find another way to raise the roll center.

    If all of the physics guru's worked together on issue's I can guarantee we can all put a better product out.
     
  11. Major_Catastrophe

    Major_Catastrophe Registered

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    Bill, you can adjust the roll rate by moving the springs inboard\outboard. Moving the springs outboard stiffens the roll rate without changing the bump rate.Conversely, moving the springs inboard softens the roll rate, again, without changing the bump rate.

    Lemme know if you want the graphical explanation and I'll scan\post it. If I totally mis-understood you, lemme know and I'll stick my head in the auto document feeder and scan that too! lol!
     
  12. Bill Malicoat

    Bill Malicoat Registered

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    Major,

    I think you misunderstood me a little.

    Taken from an Automotive suspension website, it might explain it better for me.

    Wheel rate

    Wheel rate is the effective spring rate when measured at the wheel. This is as opposed to simply measuring the spring rate alone.

    Wheel rate is usually equal to or considerably less than the spring rate. Commonly, springs are mounted on control arms, swing arms or some other pivoting suspension member. Consider the example above where the spring rate was calculated to be 500 lbs/inch, if you were to move the wheel 1 in (2.5 cm) (without moving the car), the spring more than likely compresses a smaller amount. Lets assume the spring moved 0.75 in (19 mm), the lever arm ratio would be 0.75:1. The wheel rate is calculated by taking the square of the ratio (0.5625) times the spring rate. Squaring the ratio is because the ratio has two effects on the wheel rate. The ratio applies to both the force and distance traveled.

    Wheel rate on independent suspension is fairly straight-forward. However, special consideration must be taken with some non-independent suspension designs. Take the case of the straight axle. When viewed from the front or rear, the wheel rate can be measured by the means above. Yet because the wheels are not independent, when viewed from the side under acceleration or braking the pivot point is at infinity (because both wheels have moved) and the spring is directly inline with the wheel contact patch. The result is often that the effective wheel rate under cornering is different from what it is under acceleration and braking. This variation in wheel rate may be minimized by locating the spring as close to the wheel as possible.
     
  13. Major_Catastrophe

    Major_Catastrophe Registered

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    gotcha Bill.

    To paraphrase. We get bogus wheel rates because we can't model realistic front suspension geometries (in rF1).

    The midget front suspension uses a fudge that goes some way to modelling this although it doesn't overcome the non-independence of the front wheels.
     
  14. Bill Malicoat

    Bill Malicoat Registered

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    Yea that is the short answer for sure!
     
  15. Shane

    Shane Registered

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    That seems like a lot of work Bill. Have any of the dirt modders heard anything about dirt style suspensions being more accomidated for rf2 (or did I miss it in the forums somewhere)? Sounds like a dynamic track surface is gonna happen, just curious if any of the modders had been contacted for feedback.

    High anticipation for the new game.
     
  16. Hoppy

    Hoppy Registered

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    I would like to thank ISI for the forum to maybe help the dirt modders. As you can see the modders have a lot of passion for their mods. The time and effort they put into the mods shows in the final product.
    If the developers of rFactor2 can help them with the tools to advance our community, it would be a great benefit. And very much appreciated. I can only imagine the real type feel that could result if some of the issues here would be able to be accomplished.
     
  17. Vertigo

    Vertigo Registered

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    Gjon

    I think the easiest way to accomplish any goals would be to get with somebody who understands the cars.

    For non winged cars, the suspension is rather primitive to be quite honest. If somebody could go over exactly what the suspension does, and what modders have previously had issues with to simulate it, you would have a much easier direction on what you thought could be implemented.
     
  18. Major_Catastrophe

    Major_Catastrophe Registered

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    The issues with front suspension are pretty easily understood. rFactor 1 only allows double wishbone suspension on the front. This suspension means that the front wheels move independent of each other.

    Most dirt cars I know use a solid front axle suspension. Primitive maybe but it is a hell of a lot easier to keep the front wheels in alignment using this geometry. Solid front axle means the front wheels are connected and when one goes over a bump it influences the other.

    It is a common geometry for older road cars too, so it isn't a limitation just for dirt racing. I am sure the rFactor crew are well aware of the ins and outs.
     
  19. rsmelser

    rsmelser Registered

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    another small miner detail that would be nice also, would be dirt getting on the tires and body
    just a thought i had .. so i thought id post it : )
     
  20. Bill Malicoat

    Bill Malicoat Registered

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    I am taking a paper that was written by Mike Dicely and posted on his website www.hyperracing.com and posting here. It talks about how all the testing done for traction on asphalt correlates to dirt racing and some theories. This is a real good explanation on how to achieve maximum lateral and longitudinal traction on dirt cars. View attachment Rethink Dirt.pdf
     

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