John ended up with a compound fracture of his left ankle, a sever abrasion to his right knee, broken left wrist, broken fingers and abrasions on his right hand. His cat scan showed no brain injury. Kenny Bernstein was OK.
Dirt track oval cars have "side" plates. There's a wing, but the side plates are almost as large and are angled quite a bit. They're fixed though, not movable relative to the car.
No, encoding from a replay doesn't have to be done in real time. For example, MovieStudio for GPL/NR2003, does two passes, one at a slow speed to create the video, then a second pass to create the sound (.WAV) file.
rFactor includes a replay to video feature. As mentioned, for GPL and NR2003, there is a 3rd party utlity, MovieStudio, that not only makes videos from replays, but allows a player to control camera movement. (Note, MovieStudio and Windows XP don't seem to get along very well).
I didn't mean to apply when launching, but more on that below. How often is a turn on a track so slow that you're below the power band in first gear on any car?
It makes sense when taking off in some cases, but note that the traction control systems in racing cars are designed to allow optimal slippange instead of none, and I would assume that the cars speed is taken into account (as with the earlier launch control in F1 race cars). In Indy Racing League cars, the driver can adjust the slippage factor of the traction control system while racing.
Why would there be a minimum speed for traction control? Other than the initial launch of an F1 car, where traction control is iniitally disabled, but is enabled and remains enabled once the car has reached 100kph just once, I'm not aware of any form of racing where traction control is allowed but has a minimum speed.
Traction control at lower speeds is more important than at higher speeds. At higher speeds, the rear wheel torque is less due to running in a higher gear, and in the case of downforce cars, more grip.
Note that you can't change the overall force on the outer tires versus the inner tires with anti-roll bars. You can only change the distribution of forces between the front and rear. The total force on the outside tires is a function of cornerning force, center of gravity, and the distance between the tires from side to side (track), (and track camber).
I know that in other games, the visual surface is unrelated to the actual track surface used for the physics. For one thing, there's no need to compose the actual physics surface as a bunch of triangles / polygons for video rendering.
Assuming all this is true, then I sit corrected. I'm just thinking that trying to simulate flat spots would be difficult. I would imagine that trying to include dynamic contact patch area size and deformation in addition to the normal slip / skid formulas used, and now flat spotting seems like it would be pretty cpu intensive. With a 2 foot diameter tire, 150mph translates into 35 revolutions per second, or 1680 tire segments per second (35x16x3). Maybe I'm underestimating the speed of current cpu's in PC's.
So getting back on topic here, it does seem like the hot spots take too long to cool off.
Also in addition to the air, wouldn't the track also be a big contributor to cooling of the tires on straights for the front tires and also for the rears at higher speed where rear wheel torque is less?
That same utility also slows the deeper tread heat and it takes much longer to heat up. When I did Norschleife hot laps, I'd start at the final straight near the end of a lap. I'd nose the car up to a fence then spin the rears for about 2 to 3 seconds, then I'd make a pass up the straight, and lock up the tires 3 times, back down the straight to lock em up 3 more times, then another uturn and it was off to run a hot lap. Obvisouly GPL didn't have a flat spot algorithm, and this method was common practice to avoid having to do a pre 8+ minute warm up lap.
Only if the simulation is reasonably close. I'm not sure a 16 segment model is close enough. Which is more accurate, using a table of values with linear interpolation or an equation? Say you're trying to model one cycle of a sine wave. The choices are a table with 1000 values, or a cubic equation. In this case, the table more closely approximates the sine wave. The table eats up more space, but the calculation time is faster. Now a ninth order equation might prove to be closer than a 1000 entry table, but the calculation overhead is much larger.
Maybe it would be more accurate to state my point that the cpu overhead budget might be better spent on other aspects of the simulation (general tire, suspension, chassis, areodynamic aspects) than on hot or flat spots.
My point is that while 1000+ segments may be more realistic than a "less sophisticated" canned effect, < 100 segments is probably less realistic than a canned effect. The segment approach only works well if there are a huge number of very small segments, but this would be a large cpu overhead.
Locking up the brakes could have been handled in a simpler fashion without all the work involved in LFS. This is something that only happens when a driver makes a mistake. If in the real world, flat spotting a tire results in having to change the tires, then just requiring a pit stop with a tire change would have been a lot simpler to implement without all the issues of a partial solution via LFS's tire sectioning. It could have been handled similar to the damage modeling in LFS.
In my opinion, this is one aspect where the accuracy isn't that important. You flat spot a tire in game; does it really matter if a game doesn't get the flat spot amount correct to the nearest thousandth of an inch?
There are other aspects to realism in a simulator not involving driver mistakes or driver style that I don't think any game will acheive, but it should be the goal to get close. This is where I think the effort on LFS should focus, rather than worrying about how to similate a condition that normally results in a pit stop and tire change.
I'm not a Nascar fan, but I did watch a race, and found that the coverage was very technical. The racing from one planed pit stop to the next planned pit stop was called a "run". The drivers and crew could detect differences between "runs" when the only change was tires (and fuel added, no setup changes). The lap times would vary between different sets of tires, even though the tires were as close to identical as possible. Maybe it was track temperatures (which weren't varying much for a few set of "runs"), or the amount of rubber build up on the track, but somehow, very minor differences were causing detectable differences. After a tire change, a car could transition from mediocre to good or vise versa, and it was affecting the outcome of the racing. I'm not sure if any simulation will be able to capture such subtle effects accurately.
The reason Nascar is a good example of such subtle effects is the closeness of the racing, and the consistency of lap times. A tenth of a second difference between cars tends to remain that way for quite a few laps in a row in Nascar. Most of the drivers are really consistent, so mechanical differences in the cars are more noticable.
It's not realistic, tires don't have sections, and the current implentation is flawed (hot spots don't dissapate heat into neighboring sections (or at least extremely slowly), and take too long to cool off, as noted by the orignal poster.
Define fraction of a second, .99 or .01?
It's my opinion is that the other stuff left to do for LFS is more important than getting the not quite completed hot / flat spot modeling in.
I'm not fond of the implementation of the tire sections, flat spots, and hot spots. It's the least realistic aspect of tire physics in the current version of LFS, and in my opinion, the time spent on this would have been better spent working on other aspects of LFS.
The segmentation approach is flawed, there's not enough cpu power to make a very large number of very small segments to be realistic, and it doesn't appear that surface effects versus deep tread effects are being taken into account. It's a lot of effort and cpu power being used to model what happens with a driver makes a mistake and locks up the tires, eating up time that could be use for more realism elsewhere. It's like all players are punished with this overhead to deal with the mistakes of a few players.
Personally, I would not have bothered with the hot spotting or flat spotting at all. Flat spotting is mostly an issue for high downforce cars like a Formula 1 car due to the vibration; for most race and street cars, flat spotting isn't a big issue unless it's severe, and tire wear will round out the tire fairly quickly. Hot spotting is even less of an issue because it generally only affects a thin section of the tread and quickly dissapates.
The traction was probably less, but not by much, with those tires, and maybe it was all the force (torque) that the engines and clutches at the time could deliver.
If the tires were spun hard at the launch, it would mess up the run, but once past the initial launch, if the tires started spinning the drivers could apparently stay on the throttle.
I couldn't remember the term, although I do remember seeing independent graphs for aligning torque and lateral force.
Other than clowing around in go-karts as a kid (where spinning them was a common goal), and in my cars at a nearby large parking lot for informal pro-solo type events, or on fun runs at a track. My only true track experience with side by side racing has been with indoor karts at K1 speed, (www.k1speed.com) in Irvine, where everything happens real quick. The fast way is to keep the kart sliding (drifting) a little, including using some deliberate oversteer to rotate the karts for the tighter turns to line it up for corner exit. The steering does get lighter once the tires are drifting, but it's hard to notice when the karts are pulling well over 1g in the turns, and this side force on your body is the dominating force that you feel, distracting a bit of the feel in the steering. It's not that big a deal, because you can feel the entire kart drifting much easier than trying to sense what going on with the steering wheel. Unlike normal shifter kart racing, since they own the karts, they don't allow all the bumping that goes on with normal kart racing, where it appears the common passing method is to stuff your cart inside another and use the other as a berm.
The Caterham I used to own didn't feel that much different than a go-kart, as it's bascially just an oversized go-kart anyway. Similar to the go-karts, it had some lift throttle oversteer (not as much as the karts, but I suspect they are playing some games with the karts computer setup, as you can't power oversteer them, the motor cuts out if the kart is yawed too much).
Now with the Z06, the power steering provides a lot of assist, so there's not a lot of steering wheel feedback, but you stil get plenty from the car itself. I probably won't be tracking it because the tires for it are so expensive.
Personally I have more fun sliding the cars and karts around more than I should for best lap times, as I don't do it very often, so it's just a fun thing for me.
Regarding longitudinal grip versus slip, there was a time back in the late 1960's and early 1970's where top fuel dragsters posted about the same ET's whether or not the tires were spinning all the way through a 1/4 mile run. You'd see smoke from the tires for the entire run on one car, virtually no smoke from the tires on the other car and the ET's would be very close.
This isn't true currently with fuel dragsters. Smoke the tires at all in top fuel, and the ET suffers greatly.
However, because a typical stock clutch used for a manual transmission in a lot of sports cars doesn't grip well if the engine is at high rpms while the tires are not, it's a common method for magazine testers to simply find an rpm that they can just drop the clutch and spin the tires a bit for the most consistently fast launches.
Read between the lines. The physics in LFS isn't done yet, so it's not the most realistic. He mentioned that some of the cars are "awful", a reference to the physics of LFS not translating well to some of the cars in LFS.
IMO, I don't care how a game's physics is implemented, it's the results that count, not the method. Personally, I think including tables is a good idea because it makes it easier to keep up with changes in technology in suspensions, tire design, different cars. This is assuming that developers can obtain real world data.
One of the more important issues is how a car behaves when the limits are exceeded. GTR had an issue with snap oversteer at low speed, but GTR2 has fixed this. Older versions of LFS were terrible at dealing with this, either the tranny or the tire model resulted in sudden oversteer and a big loss in grip at the rear end.
For all racing sims, IMO, there needs to be some compensation for the lack of feel. My only real track time (other than just pushing my real car to the limits and beyond on a very large nearby parking lot) has been with indoor go-karts. Fast laps are achieved when they are constantly drifting through the turns, and sometimes oversteer is deliberately used in tight turns to orient the kart for corner exit. I can feel the g forces and the tires slipping.
In a racing sim, there is no feel, so the audio and/or force feedback should be changed from reality to give a player some feedback that the car is near the limits, at the limits, or beyond the limits. Although not realistic, GTRs approach where the force feedback goes away when at the limits was one way to accomplish this. This happens a bit in real life with some cars, so it's more of an exaggerated effect. Sound is the way it's usually done, with exaggerated tire sounds.
I think part of this is the newness of racing sims has worn off, and the thrill is gone. The amount of time I spend with each new game or mod is decreasing over time. I'm simply spending more time doing other non-racing sim things now.
In real life, no lift sequential shifters are faster than standard shifters, so why wouldn't a game be the same way? I've notice that LFS doesn't shift as fast as the real thing in some cases.
Fast sequential shifter (like XTRAC), turndown the sound because the rear end whine is really high pitched and loud when the car is at higher speeds.
BMW M3 GTR Race car at combined Nurburgring / Nordschleife (two laps at Nurburgring, first is a warmup, at end of second lap, the car goes onto Nordschleife. It's a pattern shifter, but apparently a no clutch / no lift one.
Which leads to a more factual based answer to the LFS vs XYZ threads. Why is it that so few of the GPL / NR2003 / GTP / ISI based top racers (alians) play LFS? Greger Huttu has moved on to ISI based racing games. So have most of the other "aliens" from the older sims. Now part of this was because LFS had buggy tire physics until the recent releases, but I still don't see much interest in the current LFS from the older "aliens", as only a few of them play LFS.
Greger Huttu is a member of Team Redline. Most of the current team activity involves ISI based racing sims. There are more Team Redline members that play the Toca Race Driver series than LFS. Aki Räsänen, aka "Lefty" is a member that appears to be the most active with LFS.
What is it about LFS that has made it a "niche" component of PC based sim racing?
Corvette Z06's 1st gear is set to redline at 61mph. A Caterham CSR 260 is also normally set to redline around 60mph. In the case of a 190hp LX6, you'll probably use 2 gears. The shift time is significant.
The LX8 was in LFS during some gaming expo. There was a video posted of it, but all the guy did was go down a straight then spin the car on purpose. I've got the video somewhere on my system ...