New Assetto Corsa Competizione Physics Blog Post

Paul Jeffrey

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ACC Aris Blog.jpg

Aristotelis Vasilakos of Kunos Simulazioni has started a new blog post series, digging deeper into the physics of the upcoming Assetto Corsa Comeptizione…


As the initial 'Early Access' release of Assetto Corsa Competizione begins in just one week's time, the team over at Kunos Simulazioni continue to be hard at work behind the scenes making adjustments and improvements to this hotly anticipated new simulation.

Already we have learnt much about the content and direction of ACC, however one of the things that are perhaps most anticipated by the community must be the physics of ACC, and how they will compare in a brand new game engine alongside the highly regarded original title.

To help shed some light on the subject, and build up the hype, ACC physics guru @Aristotelis has shared a brilliant new blog posting, the first of a proposed series of posts on the inside workings of the physics for ACC.

You can check out the full blog posting from Aris below:

Hello everybody!

The Assetto Corsa Competizione Early Access is about to begin and once again we’re ready to start a fantastic journey.

First things first, Early Access means that you get the opportunity to get early versions of the final game and have a look on the development and evolution of ACC. Obviously, once you bought the EA version, you get all the following updates of the main game for free. On the other hand we, developers, get the opportunity to collect feedback and impressions while we work, from a much bigger testing team the we could ever organize in private.

Our responsibility will be to try and update the title on the pre-announced dates, offering great new content and as stable features as possible, so that you guys can enjoy the game and keep the feedback coming.

Obviously, that means that the initial versions of the game will have limited content and features, but we are confident that we can offer the same successful evolution experience as we did with AC Early Access period.

I hope that the above is clear for everybody and the community can spread the word and inform other simracers that might not know what Early Access means.

While many of ACC gameplay features won’t be available in the first releases of Early Access, the driving physics simulation is mostly ready. Some fine tuning and some extra features are still needed, but… there’s plenty to talk about so let’s talk… physics!

So what physics ACC runs? The first test Stefano did when we started exploring the Unreal Engine, was create a version of our AC physics and make it run inside UE. I won’t go into details, I won’t even know how to explain it, but after lot’s of cursing, insomnia and head scratching, he made it. So the first initial versions of ACC had the AC physics running.

Next step and part my main job for the time, was to try and do as many parallel runs between AC and ACC:UE to make sure the physics was absolutely identical, trying to eliminate any possible placebo effects, doing laptimes comparisons and handling comparisons. Once we got absolutely sure that everything was identical, the fun part (or the nightmare part, depending on how you see it), began.

The initial idea about ACC physics, was to evolve and improve weak points of AC physics and then move on from there. Not sure if we skipped it completely or gradually moved from one plan to another… too many things have happened and to be honest, considering the end result, it doesn’t matter anymore. What it does matter is that ACC, although it might “feel” similar, it certainly is much more than that. Stefano will probably call it evolutionary, but to be honest there’s so much new stuff that I’m not sure that term makes justice.

So, heavily reworked tyre behaviour model, heavily reworked tyre heating model, heavily reworked tyre wear model all of them not just reworked values but with all new physics features, equations and data. On top of that we got reworked brake heating model… but more about all of this on a dedicated post about tyres and brakes.

Suspensions. We got completely new damper model. As you know dampers are usually simulated in sims with 4 values. Bump, rebound, fast bump and fast rebound. But… in ACC we know have full blown damper graphs. Obviously in the setup screen you guys have the usual clicks to work with, but under the surface, each click points to a different damper graph. Also, we have a completely new bumpstop system. The bumps have variable stiffness and variable ramp (graph) of their stiffness. That was actually a forced evolution of the physics, because otherwise it would be practically impossible to set properly the cars, because of the very advanced aerodynamic model… just as in real cars.

Which brings us to the aero model. Completely rewritten from scratch. This is not even an evolution, it’s a complete rewrite. Instead of creating various “wings” that each one of the generates a specific lift and drag around the car, as in AC and more or less all the simulators out there, ACC uses a new system that takes into account aeromaps from wind tunnels or CFD and applies lift and drag to the whole object as one. Doing so, it takes into account on how the object moves its aerodynamic pressure point forward or backwards depending on pitch and yaw. Before saying that this is something you can achieve with the “wings” model of AC, I can assure you it is different. The system actively moves the pressure point and can influence front or rear lift and drag, depending on what it happens in the car pitch rotation, wing angle and so on.


The end result, is a much more pitch sensitive aero platform with situations that force you to choose specific ride heights, wing angles and suspension settings to counteract the aero influence on the handling. Because of this, as in real life, maintaining the aero platform becomes crucial, ride heights are probably the most important part of the setup and bumpstops become extremely important to control the car.

The GT3 cars do heavy use of ABS and Traction Control systems, permitted by the rules. So for ACC we had to improve furthermore the ABS and TC systems. They have become quite more complex, taking into account much more information and telemetry inputs as well as having different behaviour and output result.

Obviously we also have a completely new weather system and dynamic track. The rain simulation is really a breakthrough and, modesty apart, I’m confident that you guys are going to be impressed by it. All hail Lord Kunos, he really did an astonishing work and of course I'll do my best to explain you all the various situations, simulation and techniques to get the best driving experience out of it.

TL;DR

So, I just wanted to give you a small taste of what I’m going to cover in more detail in the following days. I’ll try to write specific posts about tyres, suspensions, aerodynamics, TC and ABS, setup screen and strategy and weather simulation.

Once again, thank you for all the support you are giving us and we really hope you’re going to enjoy the initial early access releases. Looking forward to your feedback and to the more advanced releases in the next months, when ACC will really start to shine!

Using the undeniable talents of the team at Kunos, building on the lessons already well learnt from the original title, and with a nice and shiny new graphics engine to boot, ACC already looks to have the makings of a classic firmly wrapped up...

Assetto Corsa Competizione will be available to purchase on Steam Early Access from September 12th 2018.

Check out the Assetto Corsa Competizione here at RaceDepartment for the latest news and discussions regarding this exciting upcoming sim. We intend to host some quality League and Club Racing events as well as hosting some great community created mods (we hope!). Join in the discussion today.


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 Did you enjoy the new blog post from Aris? Looking forward to ACC? Do you think the game will improve on the original Assetto Corsa? Let us know in the comments section below!
 
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I could argue that Nicki Thiim finds AC horrible because of the suspension-physics either, so WTF is this about? ACC should be better and you fanbois denying even that it can be improved. How stupid is this?

no one is denying anything.
youre just making yourself look petulant now, even without the "edgy" fanboy spelling.

Like I said, its your opinion and youre entitled to it. but arguing facts with opinions or opinion based research/results is flawed, and sadly a very modern millennial snowflake method.
(see, I can use derogatory words too, fun isn't it)

and to be honest, I couldn't care less what nicki thiim has to say. the fact is I actually realise that this is a game, a simulated rendering of vehicles/racing/physics etc, I don't need to be senna to realise and expect that it probably wont mirror what its like to drive a car. its just common sense. I get enjoyment from it, im not here trying to win the12hrs of suzuka and expect to be able to in reality after pouring 1000's of hours into games
 
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I still find it amusing that people are expecting "non blancpain" related content, and complaining theres no nords or other tracks that clearly aren't in the Blancpain series....or why no street cars etc etc...

[more boring stuff about paying stuff with beers, coffees and big chain pizza]
You have to be a bit special to think that Kunos built this new platform to only make the 2018/2019 Blancpain series and nothing else ever again.
 
You have to be a bit special to think that Kunos built this new platform to only make the 2018/2019 Blancpain series and nothing else ever again.

of course, I mean I didn't really say anything of the sort, but I guess you were too busy being witty and edgy editing my post to really think about the context of what I was saying and to what purpose.

I guess me and you don't have experiences in real race-cars, so i care what he's saying when it's about cars he should know, even when i don't agree with it.

what makes you think I don't? the point is, it doesn't matter. its an approximation, not a real world exact mirroring,
 
and to be honest, I couldn't care less what nicki thiim has to say. the fact is I actually realise that this is a game, a simulated rendering of vehicles/racing/physics etc, I don't need to be senna to realise and expect that it probably wont mirror what its like to drive a car. its just common sense. I get enjoyment from it, im not here trying to win the12hrs of suzuka and expect to be able to in reality after pouring 1000's of hours into games
Ha ha, Pure Gold

You have to be a bit special to think that Kunos built this new platform to only make the 2018/2019 Blancpain series and nothing else ever again.
Don't even tease such things! \o/

Thank you @kunos and team for doing what you do. It's very much appreciated!
 
You have to be a bit special to think that Kunos built this new platform to only make the 2018/2019 Blancpain series and nothing else ever again.
Agree. F1 2018 and Moto GP 18 are very specific licenses and games. ACC looks more like AMS in this aspect, and hopefully it will be even if the focus is only on GT, there is plenty of series, classes and tracks around the world for expansions.
 
Agree. F1 2018 and Moto GP 18 are very specific licenses and games. ACC looks more like AMS in this aspect, and hopefully it will be even if the focus is only on GT, there is plenty of series, classes and tracks around the world for expansions.

erm....how can "The Official Blancpain GT series Game" not be as specific a license and game as those two...?

I think youre letting your desire cloud your reality

Assetto Corsa Competizione is the new official Blancpain GT Series videogame.
Thanks to the extraordinary quality of simulation, the game will allow you to experience the real atmosphere of the GT3 championship, competing against official drivers, teams, cars and circuits reproduced in-game with the highest level of accuracy ever achieved.
Sprint, Endurance and Spa 24 Hours races will come to life with an incredible level of realism, in both single and multiplayer modes.

that's from their official game blurb

if their intention is to be more like AMS and utilise other series/tracks/classes theyre being very coy about it.

again, I raise my point about it being like demanding open wheelers in wrc games, or tintops in an f1 series game......


ive no doubt that they might use this "engine" in the future for other projects, but I find it hard to imagine anything other than blancpain gt stuff in their officially licensed blancpain gt game.....
 
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Their partnership is with SRO, which just bought PWC and also own other series and with a new class (GT2) coming next year.
Like I said even if they focus on GT there is expansion possibilities.
I dont mind open wheels. IMO a racing game only needs GT(3 and E, maybe 4), Protos and Touring cars, nothing more.
I expect tracks expansion at least, a game like this with only 10~12 tracks is a waste.
 
Agree. F1 2018 and Moto GP 18 are very specific licenses and games. ACC looks more like AMS in this aspect, and hopefully it will be even if the focus is only on GT, there is plenty of series, classes and tracks around the world for expansions.

Far as I can tell, ACC is purely a Blancpain GT Series licenced game. But what could happen after finishing that title's updates is AC2, working from the same engine...

From the trailers or other, where did you get the impression that it's more like AMS with many categories? I don't see it.
 
Their partnership is with SRO, which just bought PWC and also own other series and with a new class (GT2) coming next year.
Like I said even if they focus on GT there is expansion possibilities.
I dont mind open wheels. IMO a racing game only needs GT(3 and E, maybe 4), Protos and Touring cars, nothing more.
I expect tracks expansion at least, a game like this with only 10~12 tracks is a waste.

irrelevant. its an officially licensed game of the series.

you expect a track expansion of f1? why would an official series sim, have extra curricular tracks added?

ok so yes ,expansion possibilities, but only Blancpain GT stuff. like Asia, EU etc, surely you can see that?
 
falster you need to relax more, way too stressed over a useless internet discussion needing to win arguments.
Anyway I'm sure you'll be very happy when ACC gets some expansions. We all will :)
Have a good day, and drink some passion fruit juice bro.
 
we are now at the crux of the matter, and at the position I never really understand.

we basically now have people complaining its not like AMS, and that theyd be happier if it was,

you will never please 100 percent of people 100 percent of the time, but to perpetually complain that in an official sim of a series, with the grid of cars, official drivers, track roster all wrapped up in a (possibly) fantastic package, is not enough and it would be better if this was in or that was in, just sums up the very entitled world we seem to live in nowadays.

we have all that already,


I don't want another game with 6000 (exaggerated) cars in and 2000 (exaggerated) tracks in, with hotlapping leaderboards, obscure eastern European locations and some car from the 70's ive never cared about.

I want an official series race sim, with full grid, race weekend, structured championships and close enough to reality engine to get enjoyment from.
 
falster you need to relax more, way too stressed over a useless internet discussion needing to win arguments.
Anyway I'm sure you'll be very happy when ACC gets some expansions. We all will :)
Have a good day, and drink some passion fruit juice bro.

im completely relaxed. im just highlighting things


im neither stressed or unhappy.

I was always looking forward to it, same as I do with all the games.

ill also be "shock horro" enjoying nascar heat 3 and Dakar while I wait,,,, im such a filthy casual.....:)
 
Simply allowing controller setting changes to be made from the car will be an improvement from AC...

Seriously I don't know why I'm hating on AC today because I think it's a good sim, but I think the latest improvements to rF2 are making it harder for me to look forward to ACC. I'm finally starting to see what people love about rF2.
 
Far as I can tell, ACC is purely a Blancpain GT Series licenced game. But what could happen after finishing that title's updates is AC2, working from the same engine...

From the trailers or other, where did you get the impression that it's more like AMS with many categories? I don't see it.

AMS used to be Game Stock Car, their contract with the Brazilian Stock Car league didn't preclude them from adding non-stock car related content to their game.

Thus far Kunos is selling the main package and not dropping any hints about any other series or random cars, which is a very correct attitude, i mean we never like when devs keep talking about DLC on their buggy half finished games, for Kunos to be hinting that GT4, F3, P2 and a 2018 Ferrari F1 are just around the corner at this point would be ludicrous!!!!

I assuming nobody here knows the ins and outs of the Kunos/SRO contract... I would say the correct attitude is to not to go in expecting much more than what you are getting "on the box" and wait for surprises.
 
I'm really starting to question if some of the guys here understand the basics of simulation.
I work for one of the world's premier simulator builders and I can tell you, there is an 'un-Godly' amount of work that goes into it.
After outfitting and test flying an airplane with thousands of sensors and accelerometers to measure just about every parameter within the flight envelope...the actual 'work' then begins.
That information is handed off to various teams of engineers...(sound, motion, mechanical, avionics and a whole host of other engineering groups)...who then have to sit down and program it for various servers to provision a motion base to replicate that sensation.
Here is where I come in, each simulator has four quarters of logged data which must overlay the aircraft flight data graphs.
Its called a QTG (Qualification Test Guide).
That simulator must match the original flight test data to within a set acceptable range determined by simulation standards.
It is used to 'qualify' the simulator initially, then used to re-evaluate on a continuous basis thereafter by EASA, FAA, CAA, JAA and every other aviation authority of countries we train flight professionals for.
Asking a consumer simulator developer to replicate that process is going to cost you way more than you could ever muster.
Stop being silly and enjoy what you get.
 

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