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 would never want to be a developer for a sim racing game the community is just... No comment.

A: We want more it realistic than rF2 physics, which is better than real life. (What was about the tire model that was completely wrong for most of it's existence, while still being praised?)

and yes even with erroneous data the rf2 tire was well above the other sims that is to say the advance it has now! :cool:
 
Aero, dampers and tyres felt always wrong in AC and i criticized it since years, especially regarding GT3-cars, because you get enough onboard-vids with telemetry to compare it. It's nice to read that this issue might be no more in ACC:thumbsup:

But my litmus test was the Nordschleife and sadly no sign it will appear in ACC, so i hope they did a good deal to add more content not related to Blancpain similar with the GT Masters, DTM etc. in Raceroom. 25 Euros is very fair and smells like there will be upcoming DLCs. I guess most of us payed more for DLCs than the vanilla Game in AC and would be kind of stupid to loose this opportunity. And working parallel on two titles could be even too much for Lord Kunos;)
 
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


you know what this game is right?

you may as well complain theres no knockhill in f1 2018 or that theres no ken block rallycross car in MotoGP 18 or something equally as silly.

just be happy theres going to be a new, quite complex sim coming, simulating a full current series with grid and calendar, which is very popular in both reality and simming and, if you have the foresight to get in early, will be getting it for the price of a dominoes pizza deal
 
Maybe I'm just being cynical, but why go through the headache of implementing the original AC physics in the URE, if only to 'evolve' it into something new (something less?). To me it sounds like expectation management.
"If it ain't broke don't fix it"
There is absolutely no reason for Kunos Simulazioni to throw out a perfectly 'enhanceable' physics model simply to start over again.
That'd be akin to a car manufacturer completely abandoning the current model, simply because they've found a way to improve the latest one in production.
The updates and implementation of new features to what were limitations, should be what excites you.
 
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"If it ain't broke don't fix it."
There is absolutely no reason for Kunos Simulazioni to throw out a perfectly enhanceable physics package simply to start over again.
Like i wrote before: aero, dampers and tyres are not working properly in AC and always did some weird changes with the setup. Especially with the slick-tyres, especially GT3 and especially bumpy tracks like the Nordschleife were pretty much undrivable when trying to do proper 8-lap-stints around VLN for example. It just doesn't work at all and if it's rF2, pCars 2, iRacing and especially Raceroom, they do a better job so far.
 
Someone said ACC will drain part of AC's user base. I say that could be a great thing indeed: people who just want to race GT3s at Spa all day every day will have a dedicated platform to do so with all the bells and whistles, while AC remains the best place to go for more exotic track and car combinations, and of course mods.
 
Like i wrote before: aero, dampers and tyres are not working properly in AC and always did some weird changes with the setup. Especially with the slick-tyres, especially GT3 and especially bumpy tracks like the Nordschleife were pretty much undrivable when trying to do proper 8-lap-stints around VLN for example. It just doesn't work at all and if it's rF2, pCars 2, iRacing and especially Raceroom, they do a better job so far.

You forgot "IMO" .... i for once cant even believe you think that GT3 Cars behave like they do in PCARS 2 .... honestly cant, but hey...
 
...while AC remains the best place to go for more exotic track and car combinations, and of course mods.
I bought the RSS-GT pack just recently and with the Ginetta GT4, Corvette C6R or Oreca FLM09 all are a good examples how physics can be much better than Kunos content. The Porsche GT1 for example is ridiculous to drive and even two racingdrivers stated, that the Porsche GT3 R is not anywhere near reality.
 
I bought the RSS-GT pack just recently and with the Ginetta GT4, Corvette C6R or Oreca FLM09 all are a good examples how physics can be much better than Kunos content. The Porsche GT1 for example is ridiculous to drive and even two racingdrivers stated, that the Porsche GT3 R is not anywhere near reality.

he did say "and of course mods"

I feel you just want to argue and infer youre some kind of physics guru/expert
 
Back on topic, Assetto Corsa Competizione has been on my wishlist for months. This pricing structure is outstanding and I hope the sell 500K on day one.
Yeah, on my wishlist too. I wonder if developers get told (by Steam) how many people have their content on wishlists?
Based on the attention that ACC is getting, there must be... dozens of us keen to buy it ;) :D
Maybe I'm just being cynical, but why go through the headache of implementing the original AC physics in the URE, if only to 'evolve' it into something new (something less?). To me it sounds like expectation management.
If it were me, I'd be doing it to gain experience with a brand-new engine and prove to myself that the reason ACC is behaving differently from AC is because the physics models/equations are different, and not because the underlying game engine is different.
 
I feel you just want to argue and infer youre some kind of physics guru/expert
Certainly more expert than the AC-fanboy-community, which is an easy job. Was driving the rF2 GT3 pack yesterday around the AC-Nordschleife and AC-Spa. Very good example how GT3-cars can be so much superior over AC and i hope ACC does a good job iron this difference out. rF2 is not like the real cars for sure, but IMO far more close than AC. And i got a temporary ban at the AC-forum saying that years ago.
 
Certainly more expert than the AC-fanboy-community, which is an easy job. Was driving the rF2 GT3 pack yesterday around the AC-Nordschleife and AC-Spa. Very good example how GT3-cars can be so much superior over AC and i hope ACC does a good job iron this difference out. rF2 is not like the real cars for sure, but IMO far more close than AC. And i got a temporary ban at the AC-forum saying that years ago.


you lost me at the admittance, and the use of the word "fanboy", a very weak warcry used by individuals who don't like when someone, just doesn't agree with literally everything they say or pander to their every whim.

I doubt youre any more an "expert" than anybody else here.

And to be fair, using your "expert" (self opinionated) computer game "awesomeness" isn't really a strong argument. its just sad

you know, just because we are here, in this forum discussing AC and extolling its virtues, doesn't make us "fanboys"..........
id imagine most of us have and drive all of the sims, I know I do.

but like I say, its just a throwaway word designed to elicit a response

I would however like to thank you for proving a good source of example for my previous post (#74) youre clearly "one of those"
 
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I doubt youre any more an "expert" than anybody else here.
I watched enough real racing that i know i can't simulate GT3-races in AC by any means. But i also test-drive enough road cars and compared my times with the real record lap times. To be far: AC does a much better job simulating road-cars and the Japanese-pack is the most popular for a reason. Not around the Nordschleife, because it's too bumpy for the damper-physics, but around VIR it was mostly a pretty good match.
 
I watched enough real racing that i know i can't simulate GT3-races in AC by any means. But i also test-drive enough road cars and compared my times with the real record lap times. To be far: AC does a much better job simulating road-cars and the Japanese-pack is the most popular for a reason. Not around the Nordschleife, because it's too bumpy for the damper-physics, but around VIR it was mostly a pretty good match.

so no, no more of an expert, just argumentative.


Your OPINION (that's the key word here) is such.

not fact though is it? its merely your opinion.

Facts don't care about your opinion.
 
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