And you're going to control their location, how? Usually a spline system consists of a handful of splines, so you can go ahead and ripple up the area a bit here and there, but you're not going to have 50 different ruts all precisely placed where you want them.
You're not going to have any control over ruts and so on using splines. You could still do the parallax bit on top of it though.
I saw an example of this done a few years back on a "professional" level driving simulator for engineering use. If I recall correctly, they used parallax mapping to create the effect. It looked quite good actually and I was really impressed with it. This worked great on mud, dirt, and snow, and you could have an unlimited number of tire tracks through it all. If I can find the videos again I'll post them here. This was done before shaders were around, if I'm not mistaken, so today it could probably be done quite well with the newer graphics card technologies of the past few years.
Once you've done it with parralax mapping, you can most likely then read the depression information as the tire drives over the ruts, then alter the collision point(s) of the tire so the tire dives down into the rut a bit when you run through it. So the visual aspect is a bit of an illusion/trick (a rather convincing one, actually), while the physics reaction to the ruts could be done quite properly as well.
Doing the same thing with multiple polys might be a stretch due to the shear number of polys that might be needed. It might be fast enough to do this in a shader, but then you don't have access to the altered vertices (as they're pushed downward when you run over them) so it'd be a bit tricky to make the car react to the ruts. Parallax mapping is probably the best way to go, but I'm no graphics guru. Scawen could school me on that with no problem and I'd happily listen
Once you've done it with parralax mapping, you can most likely then read the depression information as the tire drives over the ruts, then alter the collision point(s) of the tire so the tire dives down into the rut a bit when you run through it. So the visual aspect is a bit of an illusion/trick (a rather convincing one, actually), while the physics reaction to the ruts could be done quite properly as well.
Doing the same thing with multiple polys might be a stretch due to the shear number of polys that might be needed. It might be fast enough to do this in a shader, but then you don't have access to the altered vertices (as they're pushed downward when you run over them) so it'd be a bit tricky to make the car react to the ruts. Parallax mapping is probably the best way to go, but I'm no graphics guru. Scawen could school me on that with no problem and I'd happily listen
Sorry, they are indeed absolutely 100% synthesized. I wrote the software so can be reasonably sure of that
There are no wav files or any sort of samples in there at all. I just ran the simulations and recorded them with the Windows Sound Recorder. 
As for the tick marks, I don't know what that was. Perhaps I overflowed the sound buffer (too large/small of values) at a point or two. Usually you can hear that though as a sort of click or pop sound, which I didn't notice at all.On the positive side, I must say it's flattering to be accused of using samples there. Thanks!
From what I've read in SAE literature and been told by Doug Milliken, with motorcycle tires the design goal is to produce lateral force with camber rather than slip angle. At a certain lean angle/camber angle on a given bike there is a certain amount of lateral force that will hold the bike nice and stable. One paper I read called it a "perfect turn" or something like that. I.e., if the bike is leaning at 45 degrees it will need to corner at 1g. 60 degrees is 1.73g, etc.. (It's just the tangent of the angle in trigonometry).
So what they try to do is design the tire so it will produce the amount of force to turn the bike at 1 or 1.73g or whatever purely by camber. If you do it with camber only then you don't require any slip angle at all. That's a good thing because any slip angle causes some drag which slows you down.
Granted, I doubt any tire does this perfectly at all cambers and so on. Plus, once you start using brakes/throttle things are bound to change so you'll end up with some slip angle anyway most likely.
So what they try to do is design the tire so it will produce the amount of force to turn the bike at 1 or 1.73g or whatever purely by camber. If you do it with camber only then you don't require any slip angle at all. That's a good thing because any slip angle causes some drag which slows you down.
Granted, I doubt any tire does this perfectly at all cambers and so on. Plus, once you start using brakes/throttle things are bound to change so you'll end up with some slip angle anyway most likely.
Bingo. That's how I'll do it for Kartsim.
I think you missed the point entirely. I don't know if you've ever developed a commercial game yourself (I have), but if you're just about to finish the thing and then the publisher pulls the plug, you can not possibly release it. How on God's green earth is that Chris and Tony's fault? They weren't self publishing it. Empire was in charge, not them. That's a completely different scenario from RL. Don't for a second pretend you have any clue why it got yanked (feature creep?? Sorry, you're wrong). That's ignorance of the highest order.
Anyway, this doesn't look like they didn't have nothing going to me:
http://www.west-racing.net/newgallery/main.php
http://www.west-racing.net/new ... owItem&g2_itemId=4688
Careful not to judge without having the full story. I've worked with Tony for a couple of years now on VRC, had dinner with the both of them, spent a weekend with Gregor, and chat with all three of the guys on a daily basis. I know a bit about what really happened there and why. No offense, but you have no idea what you're talking about on this one
I've got the RL physics engine right here on my hard drive. I know it exists.
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Yeah, that's Dr. Gregor Veble, Ph.D in physics (chaos theory, specifically). We talk a lot about tire modelling and so on. Spent a fun weekend in Vienna with his girlfriend and him earlier this year.
http://www.performancesimulations.com/files/IMG_0451.jpg
That's Gregor on your left and yours truly on the right
But yes, they're still working very hard on it. Promise
http://www.performancesimulations.com/files/IMG_0451.jpg
That's Gregor on your left and yours truly on the right
But yes, they're still working very hard on it. Promise
WSC was canned by the publisher after a large marketing staff change (bunch of non-simmer PS2 type guys came in and thought it was too hard and wanted them to dumb it down, among other things that violated the original agreement that they refused to do). Not Chris and Tony's fault at all. There are tons and tons of videos and pictures of it out there. Just because it never hit the store shelves doesn't mean they didn't make something
And yes, RL is very much still in development and kicking.
And yes, RL is very much still in development and kicking.
Actually, let me rephrase my "
" I agree that it would be good to go ahead and have server options for what tires can be used, but I woudn't label the new compound as "drift tires," but use another term. It's the same thing, I'd just different choose language for it
Exactly. And in fact from test data I've seen this is exactly what happens. Both the overall grip and cornering stiffness increase as the tread wears down. This is why racers running non-slicks shave their tires, or buy pre-shaved ones to start with.
Slicks made out of some racing compounds are different though of course as they can start losing grip after just a couple of laps, perhaps due to crosslinks breaking and reattaching in unfavorable ways (I've seen some mention of this in literature). I.e., at the microscopic level the molecular contact changes. This loss of grip can be due to that and a few other different things that I won't get into here (and don't understand much myself), and even tire engineers don't fully understand it all. Friction is a sort of bizarre thing
None of that needs to be directly modelled though, really. Just some man made curves will continue to suffice.Yes, that's true. The cure of the tire is changing over time. What happens with really old tires is that they get harder and harder essentially since the cure is continuing to progress with every heat cycle, and at some point reversion can occur which basically means they sort of begin "uncuring" in a way and become getting softer. They are continuing to cure of course, but some of the properties can start reverting towards an uncured state.
I'm not sure if reversion really happens on street tires in practice though. By the time you get to that point you might have worn the tire right down to the cords. Beats me. But yes, this all changes throughout the life of a tire. Eventually old tires will probably start to lose grip as they become harder, but I haven't seen data on that so am not sure. But if you wear treaded tires down rather quickly as in racing, well, this may not happen quickly enough to actually cause a decrease in grip.
Actually, new tires can typically have 10-15% less grip than ones that have been broken in for a couple of hundred miles. From there on out as the tread wears down the grip generally continues to increase, although more slowly than in that first couple of hundred miles. (Racers also buy "pre-broken in" tires so they don't need to run them for awhile to get the grip up to normal. Pay a fee and they'll run them in on a machine for you). However, new tires might indeed feel better because the cornering stiffness is a lot lower. The tires are more floppy and forgiving (the peaks come in at higher slip angles). Feel and ultimate grip can be two different things.
It depends on what kind of rubber you're dealing with. Some rubbers (especially high grip, fast wearing rubbers found in racing) have grip characteristics that are remarkably sensitive to temperature. Other rubbers such as natural rubber and styrene-butadiene (SBR), commonly found in street tires, have virtually no temperature sensitivity until they get wickedly hot or cold, especially once you start throwing carbon black and other chemicals into the mix. This is why street tires just aren't really sensitive to temperature and you can abuse and drift them until you get to the cords before noticing any loss in grip, but grip in F-1 tires and most racing compounds is indeed very sensitive to temperature and wear in comparison. Grip is not really solely a function of temperature directly (there really isn't an "optimum temperature") but it's still a very good approximation and is certainly good enough for most sim drivers
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Thanks for the compliment.
Yeah, that'd probably work just fine. Just keep the grip vs. temp curve flatter and then at some really high temp, make the wear rate go way up and the grip go way down, or just drop the grip a bunch and don't worry about the wear rate. One can of course do a more involved model then that, but that's not a bad one at all really and the players wouldn't know the difference either way. They just expect to fry the tires at some point and have things get slippery.
Yeah, that'd probably work just fine. Just keep the grip vs. temp curve flatter and then at some really high temp, make the wear rate go way up and the grip go way down, or just drop the grip a bunch and don't worry about the wear rate. One can of course do a more involved model then that, but that's not a bad one at all really and the players wouldn't know the difference either way. They just expect to fry the tires at some point and have things get slippery.
Right..
They do get super hot, no question. I've helped out in the pits for friends at a couple of bomber races on a 3/8 mile oval. To show us how hot the tires and rims would get and illustrate that we should never try to grab the lugnuts with our fingers or touch the rim, after one of the guys took a flat tire off he threw a cup of water on it (the tire was flat from running over debris). It instantly turned into a cloud of steam, boiling right on the rim in a flash, so they get plenty hot and do so very quickly. It had to be at least 100C for that to happen of course, and probably much hotter since it pretty much vaporized the whole cup in seconds.
What's notable about it is during those races a lot of the guys are sliding the cars around like crazy coming out of the turns. I mean big angles, like 15-20 degrees pretty frequently, for two or three hours on end. Neither of the guys I was with that were driving complained at all that the tires were going off or anything like that even though they were hot enough to boil water on the rims and had been semi-drifting for hours on end on the same set of old, used tires. Basically the grip stayed the same as far as the poop-o-meter could tell until the tire came apart, which happened pretty rarely even during a three hour race. If I recall correctly, one of the tires had worn clear down to the cord near the shoulder and yet the driver didn't notice any change in how the car was driving. This is more or less what you found too, it would appear. Damage/blistering/chunking? Sure, it happens. Although it didn't happen to us with those particular cars and tires.
EDIT: I just remembered that this was a three hour enduro event where there was indeed a pit stop at the half way mark. So the wear and so on above was after an hour and a half, not three hours.
I've seen a fair amount of force data on street tires at varying states of wear and most people would be quite surprised at what really happens there. As a sim developer, some detailed things I prefer to keep to myself, but let's just say that having a tire in LFS that doesn't lose any grip until it hits the cords is not unrealistic at all, and may be more typical of street tires than anyone would ever want to believe, especially after spending so much time driving tires in many different road racing sims that totally give up after they get a bit too hot or wear down a little bit.
There are pretty well known reasons in the industry why tires do or do not lose or gain grip as they wear down or their temperature changes. This is primarily rubber property related and is a big part of the art/science of compounding. Tires can be made to do pretty much what an engineer wants them to do.
From the test data I've seen both on tires and specific rubbers, having a tire in LFS that is basically insensitive to temperature and doesn't lose grip as it wears down (until it's running on the cords or fails of course) isn't unrealistic at all, and has nothing to do with making a special "drift tire" for LFS. That's pretty much how real street tires work, so it would benefit both the racers and the drifters, and overall make racing on street tires more realistic and true to life.
It's a win-win situation for everybody. However, if the non-drifters argue against it because they like having to nurse their road normal/super tires so much and believe that's how NR and SBR functions when it's put in the thread, well... The ones driving imaginary tires aren't the ones that are in here requesting drift tires.
Anyway, my point is just that having a tire like described is actually a very realistic thing and is more typical of real street tire behavior. It's not some sort of "special drift tire" at all. Is there something wrong with having street tires in LFS that lose grip perhaps linearily as they wear down, or lose grip in a hurry as they get past their "optimum temperature?" Not really. I like it that way too because you need to be more careful with the cars and take care of the tires, and it gives more fun stuff to play with and think about in terms of setting up the car to keep the temps where you want them. Tire designers can make tires do pretty much what they want them to do. Well, road supers and normals are specially designed Scawen brand street tires, and real tires can be made that way too so they're still perfectly realistic in this regard even if they might not be so typical. But for drifting, a more typical street tire would be useful so the grip isn't changing dramatically as you go from one corner to the next and so on, and you don't wind up with miniscule levels of grip after a short time. Would such a tire be a realistic addition? Absolutely.
Drifters don't need a "special drift tire," they just need a "slightly more typical street tire." Racers could benefit from it too.
I don't drift in LFS so this is all no big deal to me really. I'm just trying to make an argument on behalf of those that want to do it and show that there might not really be a big conflict here or "realism clash" after all between the drifters and racers. When I want to go drifting I do it here in my own little ugly sim
http://www.performancesimulations.com/files/ToddSim19a.wmv
Now, where's that LX-8?
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You destroyed the tires, that's fine and happens. What happened to the lateral grip before then? Did they heat up and suddenly you couldn't do the same lap times as before? Notice any significant drop off in cornering speed? Where these tires the ones that were recommended for the car or did you pick out your own off the shelf?
I know a fellow that worked on the Firestone tread separation case a few years back as a mediator between Ford and Firestone on behalf of the government. He told me what the tire data looked like both before and after the tread was completely removed from the tire, including a lot of the cords. Yes, the tire was destroyed, but what happened to the grip is probably not what you'd think.
Nothing theoretical about real tire tests.
This isn't an issue of tire destruction, really. You can let the tire cool back down and you'll regain the grip in the sim. Different scenario from what you're describing, I think.
I know a fellow that worked on the Firestone tread separation case a few years back as a mediator between Ford and Firestone on behalf of the government. He told me what the tire data looked like both before and after the tread was completely removed from the tire, including a lot of the cords. Yes, the tire was destroyed, but what happened to the grip is probably not what you'd think.
Nothing theoretical about real tire tests. This isn't an issue of tire destruction, really. You can let the tire cool back down and you'll regain the grip in the sim. Different scenario from what you're describing, I think.
Sorry, I only share that sort of thing with Doug Milliken, Gregor Veble, and Chris West.
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Indeed. It's ironic there's actually a debate going on between two supposedly opposing sides when this would simply benefit everyone, isn't it?
How would they know?
Of course it doesn't. Nor would it have to.
That's a problem. Physics by polls and popular non-scientific consensus does not equal reality.
What really happens to a street tire when it wears a few 1/10ths of an inch off the tread? Obviously? How so? Because there's a curve there? I know a bunch of guys that do the same thing and it's not based on real data at all. There isn't much of it out there.
That's fine, I understand how the relationship between grip and temperature and so on works. If one chooses not to believe that, I'm not twisting arms to change anyone's mind.
I disagree that it doesn't belong here. As for the first comment, I covered that at least three times now so won't repeat myself again.
Good advice and you're quite right. Think I'll take advantage of it
Yes, I have. Not for extended periods of time though, just an occasional fun slide now and then or a 360 or two on the freeway at 75-80 mph
Anyway, I was not suggesting that the tires in LFS heat up too quickly when drifting. If you'll read my posts again, you'll see what I said was that street tires do not lose tremendous amounts of grip in reality when sliding around a bunch. Do they get hotter than heck very quickly? Of course they do, I never said otherwise. The smoke is sort of a dead giveaway, at least surface temperature-wise.
The LFS street tires lose more grip due to temperature when sliding around than a real LOCKED street tire does. That's locked, as in one small piece of rubber being cooked off, liquified, melted away with no chance to cool through a rotation of the wheel. Yet that has more grip than a street tire here that's maybe 10-20 deg C above the "optimal temp."
For sim racing (not-drifting) people want the effect of temperature effecting grip so they can play around with the setup to try to optimize things. That works just fine in LFS. However, it kills drifters and quite frankly is not right in that situation.
Again, the rate at which the tires heat up was not my point. You zeroed in on one little comment I made and somehow missed the majority and meat of my discussion, which was about the amount of grip the tires lost after they DID heat up.
So, I'll try this one more time:
Drifters in LFS need a tire that loses about as much grip in reality due to temperature as a real tire does. Who cares what the temperature is at the end of that or how quickly it heats up? It will heat more or less to an equilibrium temperature at some point and stay there lap after lap. At that temperature, on a street tire the grip should not be some 70% of the "optimal temperature."
My publisher ran a Donkervoort for a few years on a European championship. One of his training days consisted of several hours of full, opposite lock, high speed drifting. Never did he discuss any significant (or even noticable) loss of grip because the tires got too hot, and that was on racing slicks that are a lot more sensitive to temperature than street tires are.
Drifters don't need some special "drift tires." They just need street tires that act more like real ones do.
I'm not even going to start talking about tire wear and what really happens there
Anyway, enough from me on this topic. Have at it, guys.
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I don't recall saying there was such a thing as a drift tire in my posts.
Anyway, my suggestion is to have a tire in LFS that is more suitable for drifting. Something more like a real road tire that doesn't evaporate and lose all its grip after a minute of sliding the car around, as in something more like a real street tire. This is most likely a matter of creating a new tire data set with some different variables for heating factors and different curves for grip vs. temperature. Your suggestion that rewriting the entire physics engine or any part of it to accomodate this is absurd.
The grip level of such a "real road tire" in relation to the other "LFS road tires" can be debated. I'm not interested enough to worry about it. As I said, I don't drift in LFS. I prefer straight up racing by far. However, I don't see what all the fuss is about in including a tire that has grip/temperature/heat rate characteristics closer to a real street tire than what the tires currently available have. Rest assured all those sorts of curves in all these sims we play are completely made up by the developers rather than having been extracted from any real data, so it would be wise to refrain from believing such a tire is imaginary while the road supers and what-not are accurate in this regard.
As I said, different compounds can work drastically differently. No sim to date approaches the basic heat/grip rubber relationship correctly by any stretch of the imagination, so let's take what we have and make the most of it
Let's have a set of tires that aren't nearly as effected by heat/wear as in LFS, that's all. There are indeed real tires that work that way. They're sitting on your car at home right now. Are they "drift tires?" Nope. Never said they were.
Anyway, my suggestion is to have a tire in LFS that is more suitable for drifting. Something more like a real road tire that doesn't evaporate and lose all its grip after a minute of sliding the car around, as in something more like a real street tire. This is most likely a matter of creating a new tire data set with some different variables for heating factors and different curves for grip vs. temperature. Your suggestion that rewriting the entire physics engine or any part of it to accomodate this is absurd.
The grip level of such a "real road tire" in relation to the other "LFS road tires" can be debated. I'm not interested enough to worry about it. As I said, I don't drift in LFS. I prefer straight up racing by far. However, I don't see what all the fuss is about in including a tire that has grip/temperature/heat rate characteristics closer to a real street tire than what the tires currently available have. Rest assured all those sorts of curves in all these sims we play are completely made up by the developers rather than having been extracted from any real data, so it would be wise to refrain from believing such a tire is imaginary while the road supers and what-not are accurate in this regard.
As I said, different compounds can work drastically differently. No sim to date approaches the basic heat/grip rubber relationship correctly by any stretch of the imagination, so let's take what we have and make the most of it
Let's have a set of tires that aren't nearly as effected by heat/wear as in LFS, that's all. There are indeed real tires that work that way. They're sitting on your car at home right now. Are they "drift tires?" Nope. Never said they were.
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