New Assetto Corsa Competizione Physics Blog Post

[Paul Jeffrey]

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!​

 

[pabletux]

you must be fun at christmas

Don´t get me wrong, I like new things and new technologies, new ways to do things, revolution.

I´m only asking what will make it special, comparing with rF2 ( people says that is the best one) in terms of physics? o comparing with what Niels is doing

 

[falster]

I was just being fatuous

 

[johnny_91]

And i think we have enough years of simulations, with "a wide range of cars in the mix", lacking cars in carclasses, features here and there and people still complaining, that ACC is not gonna be some sort of AC or PC2. The hell, the last 12 years since GTR2, people (including me) have waited for something like ACC with all those features like rain, day to night transitions, flags, pit stops and all those things, that GTR2 have made so popular in these days.

Sorry, but i have not spend thousands of euros in my rig and equipment, just to do some "quick races", drifting, or some hotlapping with a boring streetcar after work. Real racing competition with the right features is the key, to get me sitted for hours and hours in my rig and simulate a full season shedule in real time.

So hail to Kunos, for the idea to make ACC alive.

 

[Philip Antonia]

I'm with johnny_91 here!!

 

[manu68]

I have no problem at all not having a lot of content. I just hope it will allow the developpers to concentrate on the details.

And then it could be a fantastic basis to develop specific games concentrated on some famous races with the same level of details.

I personally dream about a 24h of le Mans games with 100% details, where I could attend the race of the year the same day as the real race , with all the detailled livery, all the cars , all the team, with the real weather at that time, ....24h race as a member of a team of real pilots, or as member of a team with also AI pilot taking relays, .....

We could have all seasons as DLC every year
I have a dream ......
(same could apply to 24H of Nurburgring VLN or 500 miles indianapolis)

 

[Ralf Brinkmann]

Very happy to know that the next real Assetto Corsa (AC2) will use those physics + all the future developments and improvements from ACC it's a very good thing and value. ACC may drain a portion of the original AC fans , i just hope Kunos have something to keep the rest of the AC community that have shown their lack of interest for ACC already ( road cars fans, drift fans, rally etc) hot for the next 2 years which can be long. AC is not just a game or a sim, it's a way of life, a habit, a sentimental link, peoples have found a way to include AC in their daily life like driving the Miata every Friday night, driving a lambourghini after watching the Grand Tour, recreating their own car and driving it on green hell,find friends online and build social habits, create mods etc... You cannot ask the community to change a deeply, good, installed habits...All company have to make "the mistake" during the growth process, i hope that ACC is not this "mistake" for Kunos because they may have some difficulty to recover.

Dont get too excited, they haven't confirmed AC2 or anything after ACC.
That ACC is just a "steppingstone" to AC2 is what the community hopes, it's not a statement from Kunos themselves.

 

[Dirk Steffen]

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.

This very part of this whole new thread is the very most exciting sim racing related news I have read since the release of Assetto Corsa and the releases of the RSS GT1 mod and DRM Revival Mod thereafter.

All the glittery marketing BS about new graphics from dev A, most realistic ever racing sim since the invention of the wheel (yeah right) of dev B, latest F1 features of Dev C, Hamilton's latest hairdo of blogger X, the nth re-announcement of a zombie that just isn't let to rest of dev D, the hundredths announcement of an announcement of an announcement of a developers blog feature of dev E … all of that is just distracting white noise.

Getting a confirmation of those above key aspects of further improvement deep in the physics where it counts is just making me sitting with a giddy smile from ear to ear and I cannot wait to break out the telemetry worksheets to dive into ACC.

This is going to be exciting! #WhatReallyMattersInSimRacing

 

[Ben Lee]

I hope things like FWD and AWD are still part of the physics engine and that mods can still utilise these drivetrains.

 

[Gasper Zupan]

Is there a confirmed info of how many people are involved in ACC dev team? This must be one huge team compared to AC team.

 

[The Flying Hun]

Very happy to know that the next real Assetto Corsa (AC2) will use those physics + all the future developments and improvements from ACC it's a very good thing and value. ACC may drain a portion of the original AC fans , i just hope Kunos have something to keep the rest of the AC community that have shown their lack of interest for ACC already ( road cars fans, drift fans, rally etc) hot for the next 2 years which can be long. AC is not just a game or a sim, it's a way of life, a habit, a sentimental link, peoples have found a way to include AC in their daily life like driving the Miata every Friday night, driving a lambourghini after watching the Grand Tour, recreating their own car and driving it on green hell,find friends online and build social habits, create mods etc... You cannot ask the community to change a deeply, good, installed habits...All company have to make "the mistake" during the growth process, i hope that ACC is not this "mistake" for Kunos because they may have some difficulty to recover.

Where have you gotten your belief there will be a an explicit AC2?

We hoped there would be a new race-related project by them after AC - and here it is, its ACC.

Some moths ago they said that all their ressoruces are focussed now on ACC, which means nobobdy works on Ac anymore and nobody is distracted by making plans for the time after ACC. They are fully occupied with ACC, and this will not change in the coming months and until mid next year or so, I think. If not even longer.

Any other assumptions about the time after ACC and about AC2, is just moonshine: unfounded rumour, hear-say, nothingness.

And I find it strange that one already gets mentally ocuupied with somethign that might come after the next big thing or not, when the next big thing has not even been fully delivered - and has not been fully consumed and gotten used to by the consumer.

Next things next. And next is ACC.

 

[thepharcyde]

oh I was looking fwd to be forced to take alternate lines based on amount of watter on the track

Might like to update their website to reflect this.

"Unreal Engine 4 guarantees photorealistic rendering and an accurate representation of scenarios, car materials and weather conditions. Thanks to the multi-channel audio sampling of real GT cars, the game conveys captivating and immersive acoustic surroundings and realistic environmental effects."

 

[Diogo Goetz Brand]

Don´t get me wrong, I like new things and new technologies, new ways to do things, revolution.

I´m only asking what will make it special, comparing with rF2 ( people says that is the best one) in terms of physics? o comparing with what Niels is doing

Sorry for the OT, but since you seem genuinely interested in the subject, and not in starting a fight:
It's amazing how every time someone talks "Simracing physics" someone says something like "What's the point of talking about the physics in Assetto Corsa, or Iracing, or whatever, if the physics from Rfactor 2 and AMS are so much more realistic?" like a broken record.

I'm not saying RF2 and AMS don't have more realistic physics than every other game, as I said on my previous post, I actually don't care, but some things you have to consider as well.
What's the point of having physics more realistic than real life itself if everything else on the game is unfinished, If you can't find too many people to play with, if every DLC costs more than most full games, if modding is so difficult that they had to bring back the tyre model from rF1 and so on?
You have to spend days on the game just to learn how to dial in the settings before you can actually enjoy it. It's all a matter of compromise, sim racing fans behave like realism is the only thing that matters, and that's definitely not the case, as with everything else, it's a matter of compromise. If at the moment AC is more popular than Rfactor 2, and even ISI abandoned the game before S397 took it over, maybe it's because they focused so much on physics that they forgot about several other factors that matter for the players and their super accurate physics didn't succeed as they were hoping.

My second point: Why do we care so much about realism if over 90% of us is never gonna drive a real race car? Why do we need to improve our skills on the most accurate simulation possible if we're only gonna use that to play with our toy wheels at our basement most of the time?

And my third and final point: If Assetto Corsa and Iracing, for example, are so unrealistic compared to AMS and especially rF2, why is it that several professional drivers play AC, and even more play Iracing? I mean, they might as well play Need For Speed to practice if both of these games are as unrealistic as rFactor players claim, yet I'd dare saying that even AC may have more pros playing it than AMS and rF2 combined, not to mention Iracing, which seems the most popular of all between them.

So the next time you ask yourself "why do people play other games that aren't as realistic and as complex and as precise as the ones I play", this might be your answer.

 

[Brent Mills]

Disclaimer: possible armchair expert opinion ahead!
Does anyone know what the FFB refresh rate will be in ACC. I may be wrong here, but it's my understanding that RF2's ffb feels so amazing because it is running at a very high refresh rate. I had a similar experience in IRacing a while back where someone created a service that updated the ffb refresh rate to 120hz from 60hz or something. The difference in fbb was night and day in terms of how nuanced and detailed it was. The only problem is it created unacceptable input lag which made catching slides almost impossible. So I wonder if ACC is getting a refresh rate upgrade in ffb?

 

[Ole Andreasen]

Why do we care so much about realism if over 90% of us is never gonna drive a real race car? Why do we need to improve our skills on the most accurate simulation possible if we're only gonna use that to play with our toy wheels at our basement most of the time?

AMEN to that Diogo Goetz Brand

 

[pabletux]

Sorry for the OT, but since you seem genuinely interested in the subject, and not in starting a fight:
It's amazing how every time someone talks "Simracing physics" someone says something like "What's the point of talking about the physics in Assetto Corsa, or Iracing, or whatever, if the physics from Rfactor 2 and AMS are so much more realistic?" like a broken record.

I'm not saying RF2 and AMS don't have more realistic physics than every other game, as I said on my previous post, I actually don't care, but some things you have to consider as well.
What's the point of having physics more realistic than real life itself if everything else on the game is unfinished, If you can't find too many people to play with, if every DLC costs more than most full games, if modding is so difficult that they had to bring back the tyre model from rF1 and so on?
You have to spend days on the game just to learn how to dial in the settings before you can actually enjoy it. It's all a matter of compromise, sim racing fans behave like realism is the only thing that matters, and that's definitely not the case, as with everything else, it's a matter of compromise. If at the moment AC is more popular than Rfactor 2, and even ISI abandoned the game before S397 took it over, maybe it's because they focused so much on physics that they forgot about several other factors that matter for the players and their super accurate physics didn't succeed as they were hoping.

My second point: Why do we care so much about realism if over 90% of us is never gonna drive a real race car? Why do we need to improve our skills on the most accurate simulation possible if we're only gonna use that to play with our toy wheels at our basement most of the time?

And my third and final point: If Assetto Corsa and Iracing, for example, are so unrealistic compared to AMS and especially rF2, why is it that several professional drivers play AC, and even more play Iracing? I mean, they might as well play Need For Speed to practice if both of these games are as unrealistic as rFactor players claim, yet I'd dare saying that even AC may have more pros playing it than AMS and rF2 combined, not to mention Iracing, which seems the most popular of all between them.

So the next time you ask yourself "why do people play other games that aren't as realistic and as complex and as precise as the ones I play", this might be your answer.

You missed the point completely, I´m not saying anything, I´m only asking. Anyway, sorry to ask something in a praise news, it will not happen again.

 

[ilema]

Where have you gotten your belief there will be a an explicit AC2?

We hoped there would be a new race-related project by them after AC - and here it is, its ACC.

Some moths ago they said that all their ressoruces are focussed now on ACC, which means nobobdy works on Ac anymore and nobody is distracted by making plans for the time after ACC. They are fully occupied with ACC, and this will not change in the coming months and until mid next year or so, I think. If not even longer.

Any other assumptions about the time after ACC and about AC2, is just moonshine: unfounded rumour, hear-say, nothingness.

And I find it strange that one already gets mentally ocuupied with somethign that might come after the next big thing or not, when the next big thing has not even been fully delivered - and has not been fully consumed and gotten used to by the consumer.

Next things next. And next is ACC.

I don't know how much Kunos got from BP or any flashy sponsors but ACC will not make so much sale from the community. The marketing is already showing it, they are selling BP (the watch) mainly in every post etc. They will need to make AC2 to make the huge community support back. The AC dev stop was a bit abrupt, Do not underestimate the power of an unsatisfied community many sim already paid the price even if they had the best physics etc in the world . I love GT racing but ACC is too specific game and it's even inside a pool where many games are offering similar experience SOON logically it will attract specific portion of the community, may be a tiny . I'm a devoted AC ambassador but even if i want it i don't get this kind of enthousiasm with ACC and i'm not the only one. I like to think that it's an R&D for AC2 , with this way it's fair and i'm oki with that. Wait and see

 

[ilema]

Dont get too excited, they haven't confirmed AC2 or anything after ACC.
That ACC is just a "steppingstone" to AC2 is what the community hopes, it's not a statement from Kunos themselves.

The community supported AC and made Kunos what it is today...what it asks should be taken seriously

 

[Gergo Panker]

Is there a confirmed info of how many people are involved in ACC dev team? This must be one huge team compared to AC team.

We are around 30.

 

[Kenny Paton]

The community supported AC and made Kunos what it is today...what it asks should be taken seriously

The end product was what made AC successful, and that drew in the community,
If it had been a bad game it wouldn't have had the love of sim racers.
Let's not stray too far off topic please.

 

[Emery]

Ofcourse i have a steering wheel ... It's hard to explain because it's so obvious, the steering feels "springy" in AC, and that's why i said 0 or 90°.

Springy... yes! Had to detune that in the Fanatec settings.