Quote from DeadWolfBones :

[...] Doesn't make a lot of logical sense, but that's how it is.

Just like everything on iRacing

With respect to low slip angle and low speed grip, if someone leans against a stationary car, it doesn't slide off the road, even though there is no slip angle. The resistance force is based on the sidewall defection, not slip angle. I would guess that at most speeds there is a corelation between sidewall flex and slip angle and it is easier to work with slip angle curves. But this seems to break down at lower speeds. (GPL uses 6 m/s as a cutoff to switch to a different method.) netKar Pro had problems with cars "gliding" when supposedly stopped.

Quote from baSh0r :

Just like everything on iRacing

Well, I was referring to the real life behavior, but yeah, that too.

Quote from SidiousX :

Richard Towler is complaining on facebook about how much iRacing's physics are crap.

To be fair, he's right.

Well at least latemodels on road tracks is still fun.

Quote from codehound :

With respect to low slip angle and low speed grip, if someone leans against a stationary car, it doesn't slide off the road, even though there is no slip angle. The resistance force is based on the sidewall defection, not slip angle. I would guess that at most speeds there is a corelation between sidewall flex and slip angle and it is easier to work with slip angle curves. But this seems to break down at lower speeds. (GPL uses 6 m/s as a cutoff to switch to a different method.) netKar Pro had problems with cars "gliding" when supposedly stopped.

But that is totally separate issue. About every sim ever has had that same problem. Iracing has it, lfs had it and so forth. Apparently the problem is that when the car is stationary it is hard to keep it in place. The physics engines have troubles keeping the tires connected to the road surface in the right way. Basically you get tiny amount of slip but the physics engine does not see it. The numbers the physics engine need to calculate are close to 0 which makes it very unprecise at that very situation.

When you get up to speed that problem should disappear because you are no longer dealing with extremely small numbers. Basically the difference between 0.001 and 0.00001 is 100-fold but in essence it is still a 0. These numbers cause tiny changes to the car position which cause it move.

It's that or something totally different

Quote from Hyperactive :

The numbers the physics engine need to calculate are close to 0 which makes it very unprecise at that very situation.

This may be correct, but I find it hard to believe that programmers of this ability can't do a simple 'near zero' test on acceleration and velocity and set them to absolute zero.

From what I have seen the programs know the contact patch is on the ground so that the distance to the wheel rim is known and they calculate a vertical force based on the vertical spring rate of the tire. This can be easily linked to tire pressure, etc. But for lateral and longitudinal loads the contact patch's position relative to the rim is not known. Slip angle and slip ratio are combined with empirical equations (such as the Pacejka formulas) to compute the side and longitudinal loads with results based on formula coefficients and not actual tire properties. These coefficients become the guesses that have to be played with to make the tires feel real.

Hopefully the new tire models for iRacing, LFS, and rFactor2 will work on the offsets of the contact patch from the wheel rim in all three directions to get loads based on tire sidewall and tread properties.

http://www.engadget.com/2011/0 ... -the-switch-on-the-world/

Quote :

Charlotte Motor Speedway and Panasonic held an event yesterday to celebrate the completion of the new world's largest HD screen, which measures at 16,000 square feet (200 feet wide and 80 feet tall). Of course, the only natural thing to do when face with a screen this size is to play videogames on it, and CMS got very meta by bringing out NASCAR driver and simulation racing fan Dale Earnhardt Jr. to turn a few laps on the track in iRacing on the brand new display.

Will he be in the grandstands on the other side of the track?

I know this is just repeat of what's on the iRacing thread, but it is impressive and I thought others without access would like a looky. Dale's sitting in a PC rig cockpit down near the crowd. He has his own local screen and the big screen is from a spectator account. Eric H. from iRacing says it's "1024x768 ... it's what fit best with their screen handling software"



http://lockerz.com/s/100510865


http://yfrog.com/gzmlgzfjj

Another Pic: http://twitpic.com/4vz1x0

Article: http://www.jrmracing.com/news/ ... torsports-briefing-may-10
VIDEO: http://www.charlottemotorspeedway.com/media/news/589207.html

You know, people can knock iRacing's pricing and scoff at the physics and take the piss in any way shape or form; which they do a lot in this thread and others... but, they (iRacing) sure have done A LOT to expose sim racing, and give it credit for what it is - not just another video game. Wide exposure for iRacing is vastly beneficial for the entire genre as a whole, like it or not. People will even hear about LFS through iRacing circles of course and as the debates rage on, many will try LFS just out of curiosity through word of mouth even though iRacing might have been the catalyst. What iRacing is doing is just very good for this niche industry.

Well yeah, when you have money on your side you can expose anything. Too bad they don't have the knowledge/brain power in the physics (not just tires) or netcode department though.

Quote from PMD9409 :

Well yeah, when you have money on your side you can expose anything. Too bad they don't have the knowledge/brain power in the physics (not just tires) or netcode department though.

Then why don't you head over and do it yourself?

Quote from PMD9409 :

Well yeah, when you have money on your side you can expose anything. Too bad they don't have the knowledge/brain power in the physics (not just tires) or netcode department though.

Heh, kind of surprising coming from you especially as a North American client.

The net code is far and away above LFS in my sole limited experience, and being in FL last I checked I'd have assumed you would've had similar experience. But I suppose that's an endless debate since ISPs and PCs have just as much to do with the equation as programming. Being on the wrong side of the pond could obviously create bias for me for iRacing however. I've just had vastly less random "intersections" and bizarre moments, less warping, and less lagolisions in iRacing as a whole. Your mileage may vary; maybe splurge for a better connection?

As for non-tire physics I am dying to read what you could come up with assuming it's not announced iRacing incoming features. Collisions & damage are on average much more believable than LFS (though you can quickly youtube massive failures of each sim, big deal) and the rest is elementary physics, especially for these folks.

Money on your side doesn't buy you everything; I think you might be a bit naive about business saying something like that. No organisation wants to embarrass itself, much less massive ones - you go ahead and try to coerce a massive organisation into doing business with you, let me know how it goes... You will need a shitload of persistence and tenacity, and some talent, and a product you can manage to convince them with. Trust me, words are not enough.

Quote from SidiousX :

Then why don't you head over and do it yourself?

They wouldn't hire me even if I could. Give me the 18 million dollars they started with, LFS as a backbone (as was NR2003), I'll hire Scawen, Eric, Vic, some others from this community, and then we can see who would win.

Can I get that in cash btw?

Quote from Ball Bearing Turbo :

Heh, kind of surprising coming from you especially as a North American client.

Not always me, alot of it is watching races. A class races, as well as DWC incidents have many "phantom 4x's". Knowing that nearly all of them live in the US (oval DWC), its kind of surprising seeing that from them..

It's awful to see it when they hook the guys rear end and both cars go flying off track. Then you look at the replay just to see the contact really never happened. I've seen it in 3-5 times in the past week, at Dover (trucks), Darlington (Cup), Mosport (Indy), and F1 (Road America).

Quote :

The net code is far and away above LFS in my sole limited experience, and being in FL last I checked I'd have assumed you would've had similar experience. But I suppose that's an endless debate since ISPs and PCs have just as much to do with the equation as programming. Being on the wrong side of the pond could obviously create bias for me for iRacing however. I've just had vastly less random "intersections" and bizarre moments, less warping, and less lagolisions in iRacing as a whole. Your mileage may vary; maybe splurge for a better connection?

Verizon FiOS 30m down, 15 up. Running iR at a steady 50-60 FPS. The prediction code is smoother in iR, I'll give you that. But you are not able to run as close IMO at all. And when people are so afraid of SR, it makes it worse. Can't have any close racing, and when you do you end up with some fake collision.

Quote :

As for non-tire physics I am dying to read what you could come up with assuming it's not announced iRacing incoming features. Collisions & damage are on average much more believable than LFS (though you can quickly youtube massive failures of each sim, big deal) and the rest is elementary physics, especially for these folks.

Actually, it was announced in beta, as they changed it many times. It was the inertia values. And if that also has anything to do with the weight of the cars, then by all means change it.

Quote :

All the cars have more accurate chassis inertia numbers, so the response rates have changed. Some cars have higher moments, some lower

Collisions and damage better? Now I will agree LFS can be too nice at times, but iR is just downright ridiculous. 5 mph into a barrier, car is dead. When you rub a wall at 185mph, that doesn't mean you are slamming into it at that speed, it doesn't mean the RF tire should cave in by 6 inches either. Why didn't the body of the car cave in? Or why didn't the rear of the car get damaged as well? Why is my car flipping through the air, but bouncing off the ground like a toy ball? Why is my car going through the ground? Stuck in the fences? Walls?

Quote :

Money on your side doesn't buy you everything; I think you might be a bit naive about business saying something like that. No organisation wants to embarrass itself, much less massive ones - you go ahead and try to coerce a massive organisation into doing business with you, let me know how it goes... You will need a shitload of persistence and tenacity, and some talent, and a product you can manage to convince them with. Trust me, words are not enough.

Money can buy you quite a bit if you spend it wisely. As long as you have a backbone software application, one that handles things well (NR2003), tweak the graphics a bit, tweak the spreadsheets a bit. Then spend millions scanning real world tracks and cars. Hire some programmers to put it all together, and then find ways to advertise to get maximum exposure and to form a hype train. Sounds about like their plan.


I drove with Papyrus since NR1 back in the mid 90s. "The next generation in sim racing" so far has been the level of detail in the tracks and cars, as the physics are nothing spectacular.

When you have put a long awaited "Sprint Car" into the game (sim for the sim nazis), and then when testing those "real world values", the car is doing wheelies at 140mph down straights, you have your physics model spot on.

If you don't understand that last bit:

That's what happened when iR was releasing the Sprint Car, and that's one of the reasons it was delayed quite a bit.

Quote from PMD9409 :

It's awful to see it when they hook the guys rear end and both cars go flying off track. Then you look at the replay just to see the contact really never happened. I've seen it in 3-5 times in the past week, at Dover (trucks), Darlington (Cup), Mosport (Indy), and F1 (Road America).

I had one of those in T1 at Phillip Island yesterday in the Corvette. Could have driven a Vespa through the gap between our bumpers, but my race was still over.

iRacing does a lot right, and they're working quickly on fixing the things that are wrong.

Hi all,

I'm thinking about a return to sim racing. Considering re-activating my iRacing account but I have a few questions aimed at those who've spent a bit of time using iRacing recently. With all the stats and licensing features it really looks like the best thing out there for the serious sim racer. But you guys can tell me whether that's true or not.

I tried a racing 2-3 years ago and the numbers of racers were fairly limited? How big are the grids these days. Do they fill up and are there ever times when you can't get a slot in a race?

If I remember correctly iRacing only shows the racers real names. Part of the reason I'm considering a return to sim racing is to meet back up with old friends that I used to race with here in LFS. But how would I know I was racing an old LFS buddy if their LFS nickname isn't shown in iRacing?

One of the elements within LFS that I loved the most was car setup. LFS was great in terms of making small changes to set ups and being able to feel the result of the change on track. How's iRacing when it comes to car setup?

Also any general comparisions and contrasts between iRacing now and LFS would be really handy.

Thanks in advance for any comments. And if any of my old mates read this please pipe up and let me know you are iRacing. Would be great to race again.

Hi GF. The participation is pretty great for most series. Things like the Star Mazda, Grand-Am and Indycar get lots of participation and almost every race goes official, as does the F1 car. If you're interested in oval racing you will always be able to find a race, no problem. A couple of the series, like the V8 Supercar and the Lotus 79 aren't quite so good, but the members organise at least 2 races per week which always have big grids.

There really is no way to identify old LFS racers unless you know their name. Maybe we should think about organising a list on here so we can recognise them when we go out on track.

Car setups are fantastic, pretty much every option thats on the real cars are on there in iRacing. Setting up the Indycar and the F1 car is almost impossible because of the amount of setup options . To give you an idea, I've attached the iRacing supplied guide to setting up the F1 car.

I've moved onto iRacing completely now, only booting up LFS in the past 6 months to test the new test patch, but the serious lack of servers is a problem. LFS still feels very good, but iRacing just keeps getting better and better, and the NTM is due out in August which should improve things drastically.

Thanks for the info Deko. I think I'm gonna give it a try but for now I just want to pound round FE Gold with a few old LFS mates and get that out of my system first.

High cost - north of $600 (if you want it all)
High quality - check out the screenies on iR facebook page.
Tyres are a bit fudged at the mo but still very fun & drivable.
Updates to tyres & aero/drafting coming soon.
Subscription based so you have to keep paying over & over.
US company so the bias is toward american race cars, but still plenty of road stuff to choose from.
The best sim version of Spa money can buy.
Oulton/Zolder on the way.
Good community you'd fit right in @ club England. (weekly club events)
Higher hardware requirements. cpu speed/pedals/shifter.
Web based so no offline running at all. If the site goes down no one can race.
Earn credits for racing. Yep they actually pay you to race. $4/$6 for completing a season.
QA event tomorrow they are paying $3/$5 just for taking part.
Use the promo's, $10 for 3 months is a good deal.
Plenty of competitive Star mazda races (middle tier of SS).

I think that about covers most of it.

Quote from anttt69 :

QA event tomorrow they are paying $3/$5 just for taking part.

Ah, thanks. I was going to darken iRacing's door on Sunday to maximise my overlap with the (theoretical) NTM, but I'm easily bribed to come back a day early. 21:00PM (BST) ought to be pretty well attended, especially as nobody has to buy anything.

I think I'd better start from the pits though. Driving a new track with a high-ish, but highly rusty iR isn't a recipe for success.

Andrew McP

Splits are being made by qualifying time Andrew, so you won't be thrown in with high irating drivers.

Quote from DeKo :

Splits are being made by qualifying time Andrew, so you won't be thrown in with high irating drivers.

Thanks, but I can still see a start from the pits coming on. I fall into the slow but consistent category, which ought to put me nicely into a split with all sorts of random talent. :-)

I thought about getting my share of 5$, but there's an LFSCART race at the same time, righto?

Well, I prefer LFSCART(In case I can qualify).

Drove Okayama Short and Long for the first time, nice

Quote from Hyperactive :

Quote from codehound :

With respect to low slip angle and low speed grip, if someone leans against a stationary car, it doesn't slide off the road, even though there is no slip angle. The resistance force is based on the sidewall defection, not slip angle. I would guess that at most speeds there is a corelation between sidewall flex and slip angle and it is easier to work with slip angle curves. But this seems to break down at lower speeds. (GPL uses 6 m/s as a cutoff to switch to a different method.) netKar Pro had problems with cars "gliding" when supposedly stopped.

But that is totally separate issue. About every sim ever has had that same problem. Iracing has it, lfs had it and so forth. Apparently the problem is that when the car is stationary it is hard to keep it in place.

And iRacing New Tire Model seems to have the same problems as well. In the update Tony Gardner posted last wednesday, he said that the last bug that remains before the new Impala Nationwide car is released is that, when parked "there is a little shaking or minor instability."

I though this problem was only typical of the pacejka formula, which doesn't work for low speeds since velocity appears as denominator. From Kaemmer's explanation video on last october ("Dave Kaemmer iRacing Tire Model Discussion" on vimeo), it seems they are using a "brush model" instead of pacejka, but still appear to have the same zero-speed issue.