What physics are actually simulated in GPL.

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> I would be interested to know what features are actually modelled in GPL. > Aerodynamics obviously are modelled to some extent when slip streaming and > the tyres are modelled pretty accurately. > Can someone please provide a list of known features. > -----------== Posted via Newsfeeds.Com, Uncensored Usenet News ==---------- > http://www.newsfeeds.com The Largest Usenet Servers in the World! > ------== Over 73,000 Newsgroups - Including Dedicated Binaries Servers ==-----

I do not have any listing of this sort, but this is what I can tell from the specs and personal experience. They model the car as a rigid body with mass and rotational inertia, which they use to update the rotation and velocity of the car based on all the torques relative to the center of gravity and forces acting on it. They model the engine with all the torques it exhibits on both the chassis and the wheels. It appears the rotational inertia of the wheels is modelled, I am not sure about their mass though, as the problem with these two is the time-step required to do it accurately. The suspension movement is modelled, but it appears that the movement is only in the vertical direction with no changes of camber or scrub, so probably the suspension geometry is a bit simplified. I could be wrong here, though. The aerodynamic drag is modelled, and so is slipstreaming. There appears to be no aerodynamic effects with running the front of your car low and the back high or the opposite (i.e. downforce and `upforce'), but then again, I am not really sure. I also do not know if the drag increases at high slip angles, although the increase is probably negligible with respect to the drag from tyres. The grip/traction forces are modelled really nice, with both slip angle and ratio modelled. The effect of slip ratio can be seen when stepping on the accelerator and the revs increase instantaneously, and then again drop when the accelerator is released. These are mostly my observations, so I again stress that I might be wrong. Greetings, Gregor

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> I would be interested to know what features are actually modelled in GPL. > Aerodynamics obviously are modelled to some extent when slip streaming and > the tyres are modelled pretty accurately. > Can someone please provide a list of known features. > -----------== Posted via Newsfeeds.Com, Uncensored Usenet News ==---------- > http://www.newsfeeds.com The Largest Usenet Servers in the World! > ------== Over 73,000 Newsgroups - Including Dedicated Binaries Servers ==-----

I don't remember where I read it, but there was a list someplace. The article I read described that they started with a rigid body. The suspension arms are connected to the body and can move up and down relative to the body on one end and are attached to the body on the other. The king pins are connected to those arms and can turn left/right. The tires are mounted on the kingpin axles and can rotate.. ect...ect.. ect I would take a guess that that article is what you are looking for but I don't remember where it is. With luck, someone will know what i'm talking about and send the link!

Maybe this will be of help? : http://home.c2i.net/thepaddock/archives/exclusive.htm I know it's old etc., but atleast it will give you a little idea of the complexity of the physics engine. ed_ > I don't remember where I read it, but there was a list someplace. The > article I read described that they started with a rigid body.

I would be interested to know what features are actually modelled in GPL. Aerodynamics obviously are modelled to some extent when slip streaming and the tyres are modelled pretty accurately. Can someone please provide a list of known features. -----------== Posted via Newsfeeds.Com, Uncensored Usenet News ==---------- http://www.newsfeeds.com The Largest Usenet Servers in the World! ------== Over 73,000 Newsgroups - Including Dedicated Binaries Servers ==-----

Don't drive F3 :) I thought it was proved to be unmodelled - hence the +max values being used in everyone's setups? Well, there's lots of little problems - e.g. warping into places and getting thrown skyward. Also, from what I've seen, the cars are very simple boxes for collisions - 4 wheel boxes & a chassis box. Not highly detailed :) You can drive into the end of a thin wall, for example, and the car will drive through as if it weren't there... 16rpm is the limit, or is it 8? No I'm not obsessed with detail! I guess I could also have mentioned the two things that are really bugging me about GPL: No depth/z buffer :-( No curved track cross-sections (i.e. banking is rubbish) Oh, and the physics of flight are a bit weird... Roll on GPL2 :) Phil (grooooovy)

I think you'll find that Phil means that almost all hotlappers use -0.500 toe out at the front, but that the difference in rolling resistance and top speed is not modelled. (At least it seems to be the case - try Talladega.) Rafe Mc

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> > +max? what are you talking about? do you mean the 1 lb increments in > >the roll bars and springs? That's an add-on application developed long > >ago. many people use it. > I think you'll find that Phil means that almost all hotlappers use > -0.500 toe out at the front, but that the difference in rolling > resistance and top speed is not modelled. (At least it seems to be the > case - try Talladega.) > Rafe Mc

You are absolutely correct! I've tested this some time ago to see if there was a difference. There are none except that you can alter your turns with a quicker or less quick(?) turn in, or mid turn, or exit, with adjusting toe. There is also strait line wobble that toe can help with. There is just no difference in top speed or differences in acceleration to that speed (time or distance). -------------- Fuel: I also tried Fuel mileage.. Tire pressures are modeled in that the higher the tire pressure, the better mileage you get. This ranged from 0 (lowest pressure) to an added 3/4ths to a full lap (highest pressure) at Dega in the F3. Distance traveled (of course) was modeled. Ran up high and then down low. I ran out of fuel down low about a lap to a 1 1/4 after the high. err.. I traveled less distance down low and there for lasted longer then the longer distance of running high. I also did a drafting fuel mileage test. I followed the drawn race line and ran out of fuel at X point on X lap. I had someone draft me as close as they could and followed that same line. It only gave me just under a 1/4 lap more. I did the same but followed and gained a little more then 3/4 lap more from when I was alone. I still have to run the (alone) test at half throttle to see how far that gets me. If I go considerably further, say 2 laps, then fuel mileage is only dictated by tire pressure, distance, and throttle position. This test would decide if drafting make a difference or not.