Physics Which tyre model does assetto corsa use? (Ex: Magic Formula, Pacejka 96', etc)

[diego.bula06]

Hi everyone

I want to start modding mainly to develop a personal project of designign and building a race car protipe using AC as a development and test tool before manufacturing. I have read a lot and investigate about the physics in AC, vehicle dynamics and there is somenthing that I still don't understand: AC uses his own tyre model or is a real world tyre model like the pacejka 96'.

I am asking this because a I have already chose the tyres for my prototipe, i have the tyre data and even the pacejka 96' coefficients. I would like to model the tyres for my design in AC but I don't know what model is used in the game.

I hope you can help me.... I have attached the tyre data I have.

Thank you

 

[Stereo]

It's their own tire model, pretty much a brush model with parameters available in the ways that are usually measurable (peak slip angle, dropoff amount, etc.) as far as I know the pacejka models are missing too many important inputs to really be usable for a general sim.

 

[StefanoCasillo]

as far as I know the pacejka models are missing too many important inputs to really be usable for a general sim.

it's still a very nice formula that captures the static tyre behavior pretty well if you understand the relationships between the various parameters. You can still derive a pacejika parameter set that will look very similar to what it's possible to get in AC just by starting with peak height, peak location and fallof asymptote with the added bonus of param(s) to control the linearity of the curve at low slip angles (one of the problems of the brush model) and the size of the transitional curved range around the peak.

The real problem with pacejika data sets is that they are usually computer generated fit of the parameters over a set of experimental data points.. and since the tyre measuring machines available can only really measure the forces at low level of slip angle the resulting generated params for the pacejika will match very well the "grip" part of the envelope and totally miss the mark when it comes to the final part of the transitional envelope down to the "total sliding" part.

Those 2 final parts of the envelope is where most sim races spend most of their time (ie overdriving ,sliding, spinning out).. so getting those wrong means the entire sim will feel off.. and this is why pacejika got such a bad rep in the sim racing world.. it was usually used with the kind of crazy numbers you can find in the doc that OP posted or in some books available at the time, with no understanding of the effect of those numbers resulting in simulation that felt aweful.

Niels has a fantastic video about this for those who wants to dive more in the topic:

 

[gold333]

I have heard that real race teams use simulators based on proprietary rF code and plug ins coupled to x win.

I have never heard of a racing team use AC based simulators but I’d love to be proven wrong.

 

[Johnr777]

I have heard that real race teams use simulators based on proprietary rF code and plug ins coupled to x win.

I have never heard of a racing team use AC based simulators but I’d love to be proven wrong.

Some Saturday trolling I see!

 

[gold333]

Some Saturday trolling I see!

Being rude and uncivil to forum members I see!

What did I say that was factually wrong in your opinion.

 

[Johnr777]

Being rude and uncivil to forum members I see!

What did I say that was factually wrong in your opinion.

Not sure what your end goal is when you keep trying to compare rF2 and AC every chance you get.

But you are factually wrong about AC not being used by race teams

 

[gold333]

Not sure what your end goal is when you keep trying to compare rF2 and AC every chance you get.

But you are factually wrong about AC not being used by race teams

Every chance I get? I have been running AC for the past months.

and I never said rF2, I said rF1. As far as I know racing teams don’t use rF2. Redbull Racing as far as I know uses rF1 or did anyway. The monaco track on their sim video is a known mod.

Lighten up man. As I said, if any racing teams use AC I’d love to know which.

FWIW personally I prefer AC to rF1 (and maybe even rF2) simply because of the flexibility and fun factor of AC

 

[magicmunkynuts]

Every chance I get? I have been running AC for the past months.

and I never said rF2, I said rF1. As far as I know racing teams don’t use rF2. Redbull Racing as far as I know uses rF1 or did anyway. The monaco track on their sim video is a known mod.

Lighten up man. As I said, if any racing teams use AC I’d love to know which.

FWIW personally I prefer AC to rF1 (and maybe even rF2) simply because of the flexibility and fun factor of AC

I was watching this video about the Dallara Motion Simulator and he says they use the pro version of Assetto Corsa for the graphics but everything else (physics, tyres, aero etc..) are developed in-house by Dallara. I don't have any more info than that though.