Tyre Physics Model (ISI TGM Tyre Tool) Video, have people seen this?

Just wondering if people especially modders have seen this video, looks pretty impressive...

http://www.youtube.com/watch?v=5H2zGGUdfrA

Always watching rf2 vids but have never come across this one, I guess because of the way he named it.

 

Nice find was there no audio ?

 

guess not looks like some pretty deep advanced stuff, should make future mods physics awesome if people are on a high enough level of understanding to use it correctly

 

Indeed very impressive, it's hard for me to believe that a average computer system is able to manage this in realtime especially at this detail level.

 

It doesn't really manage it in real time. The TGM tool runs the tyre through an iteration cycle (which if Niels Heusinkveld is speaking the truth can last for over 4 hours) to generate a lookup table, which is then used in the real time simulation.

 

Rfactor2 is still using a lookup table? Really??

 

There's nothing wrong with that approach.

 

Lookup tables just speed up code, so you can do more things in realtime.

 

Lookup tables are the only way to use the kind of accuracy the carcass model provides in realtime without the use of a supercomputer. An on the fly dynamic model would have to be a heck of a lot simpler. The only real drawback of lookup tables is what happens when you go beyond the values in them, but on the other hand the boundaries are customizable when creating the wheel so you can essentially make it cover every situation.

Mind you, the lookup table is for the carcass deformation, the surface/tread behavior is using a realtime 6 DOF brush model (assuming I've understood the documentation correctly).

 

That's interesting, I ask myself if there is a temperature exchange between the two models?

 

But you have two displays of tyre-temps., one in the HUD that shows surface temps. and second one could be activated over the "player" file.
At the first dispplay temps. sometimes changes strongly, effected by friction, in contrast to the second one which is much more stable, this one is mainly effected by damping forces.
It seems to me, there is not wery much temperature transission between those two.

 

Both the carcass and the surface portions of the model do affect each other for very obvious reasons. =)

EDIT:

Could you point out the .plr file setting to get the other temperature to show in-game? I'd like that very much. =)

But yes, the two models do share heat between each other. If the carcass temperature is raised significantly the surface temps also tend to stay higher, and spinning the wheels incessantly (raising their temps very rapidly) will also heat up the carcass. This is what happens in real tyres as well. They are parts of the same system.

I was just reading about tyre temperature pyrometers, and the probes have a sharp point that measures the temperatures near the cord of the tyre, the rubber acting as a temporary insulator keeping the cord warm while the car isn't moving.

 

Open the file "player.plr" find the Variable "TGM Display" (under [Driving Aids]) and change the value from 0 to 1.

 

Pretty sure that didn't change the behavior of the normal tyre temp display, but it did add another temp display in the upper left corner, which was seen in some early WIP videos. That one though seems more like it'd be surface temps, due to its behavior. Try this: Drive fast on a long straight and start braking so that you'll lock the brakes totally. Let the car stop. Then put it in first and drive off veeeeeeeeery slowly. You can see the hot patch of rubber coming in and out of view in the display as the tyres rotate. It seems to be showing the size and temp of the contact patch that is currently touching the road surface.

EDIT: Forgot to say thanks!

 

doesnt a look up table kind of mean that there is a given value for every circumstance, instead of being dynamic? for example tyre load + heat + pressure + this minus that mulitplied by this, and you get a value, and then you jus have tons of these values on a grid/chart. Isnt that the wrong way to go and dont rbr, nkpro and iracing NOT use this system??... I Could be totally wrong but if I recall correctly, these look up tables were one of the main things rfactor 1 haters would use against us in arguments.....

 

What do you think the 4 hours of iteration are for? Even a dynamic system comes up with the same answer when you input the same numbers, the TGM tool just does this beforehand and at a higher resolution than a dynamic system could cope with.

The lookup tables used in rF1 btw bear little similarities with this case, since it used a Pacejka-model. Very different sort of mathematics going on there.

EDIT: Admittedly, a lookup table approach is inferior in the sense that it is limited to the precalculated values in it, but if the boundaries are set appropriately this won't be a problem.

Even dynamic systems have some boundaries. If you take a dynamic system and a lookup table based system with the same resolution and apply the same boundaries as the dynamic system has when you create the lookup table, they both will come up with the same answers in the same situation, producing an equal result. The lookup table method will run faster though.

 

Look-up tables are effectively canned values. There's nothing wrong with using them at all and is used extensively in on-the-fly simulation software. Even damage calculations (for instance for a Structural Health and Monitoring System) will use look-up tables; as long as the tables are representative then they are reasonably accurate estimations.

As in many applications (even human performance), it's the underlying trade-off of speed vs accuracy. You can't have both.