Tire model discussion thread

Hey, just starting a discussion thread about tire physics here since the one on getsatisfaction seemed to be succesful, plus I care deeply about the subject. Annnnyway, judging from this screenshot tDev posted on the Cryengine thread:

It seems as if BeamNG has exactly the same tire system as meshwheels in Rigs of Rods. Now, I'm no expert in car dynamics, but I've been reading this book along with this one lately and it has become apparent to me that the most important thing to having a realistic and good handling car is the tires. Even if your suspension, steering and weight distribution are perfect; if the tires are not realistic then it just ain't gonna feel right. Some of my thoughts to summarize what the tire model should be:

Rim- It would be fine to take the style of rims from wheels2, except you need to be able to choose the width of the rim independent from the width of the hub (so you can adjust scrub radius).

Tire- Ah, a style similar to the model in LFS would work wonders here:

1) Multi-horizontal-segmented tire carcass with each individual metal cord simulated with a beam (each wheel might be around 500-1000 beams).
2) You need to be able to choose between different types of tire. Drive an old bias-ply classic car and it will slide everywhere where a newer modern radial-tyred car will remain controlled.
3) You need to be able to set the width of the tire tread, along with how much the sidewall bulges out.
4) Sidewall stiffness needs to be independently selectable.
5) Tread stiffness needs to be independently selectable.
6) You need to be able to choose a tire grip curve in the same style RoR does a torque curve.
7) You need to be able to set the grip of the inner edges of the tire independently because the inner edges of modern tires have more grip since that is what is in contact with the road most of the time.
8) Maybe add the ability to have tire temperature affect grip, I see care slide out at races all the time because of cold tires.
9) You could have the beams connecting the tire to the rim all scripted to break at once so the tire would "pop-off" the rim if a curb is hit.
10) Make the tire like the boat hulls in RoR - if one beam is broken on it, the whole tire deflates like a boat would sink.

Looking at the above list I would think it would probably be easier to let us design our own wheel (manually place all the nodes) than just provide a pre-served-up model like RoR did (of course you could still make it an option). Just select which nodes you would like the torque applied to, which are the hubs and you're set.

Well, I think that's enough for a day, I'm gonna go lie down

 

This is looking good.

 

A tyre model similar to LFS would be lovely, but also very hard to do i believe. I'd be happy with an upgraded version of the RoR tyres to be honest

 

I hope the tyre can burst!
and i hope the tyre can pop off the hub that would be "awesomesauce"

 

That does sound "awesomesause" but I hope you can turn it off, I want to FLY off the curbs and be able to drive off.
Slightly off topic but the underbody of the car looks predefined, can it still be cut in half?

 

I think they actually just made the mesh of the truck body hidden in that photo so you could see the underlying structure. See this other pic from the Cryengine thread:

Regarding cutting things in half it was not possible in RoR but I think they said they were going to implement mesh tearing on Getsatisfaction

 

To me it looks like it is exactly the same as RoR... Everything is defined, just as the creator has intended it to be...

On topic.

I think this is a great idea! Although I believe that a proper tire simulation done with N/B can be done with less then 1000 beams, however it would probably require additional coding and physics calculations.

I remember tdev's idea for gas pocket tire simulation in the development threads on RoR about having the node's connected on the outside by beams (the rubber of the tire in real life) and the inner beams would be replaced by a computational calculation that would adjust the rigidity of the beams in the tires to simulate air pressure in some strange way that I didn't really understand. I thought it was a really good idea though and since BeamNG is still in its infancy than this might be much easier to add in now then further down the road like RoR is now.

I say all of this now because to me, if all anyone wanted to do was simulate forklifts, then I think the tire model is bang on. However, we can all agree that this is not the case and the tire's are in need of a bit of an overhaul, and I am in total agreeance with all of Nipash's added parameters for I think they would make a great tire model

 

ah, ok, thanks!