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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My second point: Why do we care so much about realism if over 90% of us is never gonna drive a real race car?
Because simulation and modding. If the game engine doesn't replicate what's needed for a good simulation, then it's worthless as a tool for the 10% who want/need simulation, who want/need to create a car that's not in the game and have the knowledge to do so.
 
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.
 
This proves my theory...ACC is going to be very much like AC with refined Look but with only a few cars and tracks!!!
I dont care about new physics details...there are many more important things to implement on a serious simulation game, like realistic sounds and damage model!!! Even realistic visual effects like tarmacs heat haze at long distances and realistic dust, etc!!!

ACC is bringing only slightly refined physics that won't have impact on most users due to lack of professional sim rigs!
Also most of the Pc's won't be able to maintain at least 60fps with the new graphics eye candy!

Despite of having a professional rig and the required hardware to run this title I am concerned about most of the users that like me will still have to wait for proper simulation titles to be created!
 
This proves my theory...ACC is going to be very much like AC with refined Look but with only a few cars and tracks!!!
I dont care about new physics details...there are many more important things to implement on a serious simulation game, like realistic sounds and damage model!!! Even realistic visual effects like tarmacs heat haze at long distances and realistic dust, etc!!!

ACC is bringing only slightly refined physics that won't have impact on most users due to lack of professional sim rigs!
Also most of the Pc's won't be able to maintain at least 60fps with the new graphics eye candy!

Despite of having a professional rig and the required hardware to run this title I am concerned about most of the users that like me will still have to wait for proper simulation titles to be created!

And you got all that from not even playing the game? That's amazing.
 
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:)
The power of an unsatisfied community? Last time I checked, two or thre em oinths ago, AC still was the most-played race sim in stema charts and it sales numbers beat that of the other contenders. Development stop a bit abrupt? Only to the mind with short memory or the mind that never was told and never rwad it in the first: already 2013 or 2014 they said somewhere they plan to support the sim until 2018. Thjat so they ended support in 2018 is not really a surprise. Me and a few others were not surprised at all. I did not reayll expect it, but I saw it coming and I was not surprised - and not angry - at all when it happened.

As I see it, its not that palyers now need to chose between AC and ACC. I think it is much more likely that ACC will just be added to the list of games played by people, and that both get used. I forsee myself deciding on grounds of my daily appetite for this or that track whether I play AC or ACC, or RR. Tracks that are present ion both AC and ACC, I will probably drive in ACC. Tracks that are missing in the one title, I will then drive in the other. I do not choose between the two, I never did (between AC and RR). I use both, and soon will use all three. Thats why I think community-wise and activity-wise the old saying "The king is dead, long live the king" is not adequate to describe the launch of the new Assetto Corsa title. For quite some time to come I expect them to be used both by many people. ACC will do the things it inbcludres in its content better than AC. But AC is the bigger content universe. And thats why it still has, imo at least, a good and long breath of life in it.

On the new physics, it sounds all very impressive, I loved to read it. But the decisive criterion in any sim, no matter the genre, is, whether physics make a difference, whether they it really find representation in the way it feels and runs and handles and drives. That is where the verdict will be found. Complexity that is not to be recognised and differentiated in perception by the player, would be just wasted.

But I observed Kunos since they released the tech demo of AC in 2013, and saw how they worked and what they did and what they announced and what came of their announcements and plans. They stuck to what they said. And so they have my trust to deliver an outstanding job once again. :)
 
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?)

B: We want more realistic dust effects, not physics.

C: No content, better play rF2...

D: Too pricey for that much content, better play iRacing...

E: GT3s can be driven at the limit by toddlers.

F: No VR on release, how could you?!

All this before anybody tried it. Kudos to the dev team for staying relatively sane.
 
This proves my theory...ACC is going to be very much like AC with refined Look but with only a few cars and tracks!!!
I dont care about new physics details...there are many more important things to implement on a serious simulation game, like realistic sounds and damage model!!! Even realistic visual effects like tarmacs heat haze at long distances and realistic dust, etc!!!

ACC is bringing only slightly refined physics that won't have impact on most users due to lack of professional sim rigs!
Also most of the Pc's won't be able to maintain at least 60fps with the new graphics eye candy!

Despite of having a professional rig and the required hardware to run this title I am concerned about most of the users that like me will still have to wait for proper simulation titles to be created!

In my opinion, what will make ACC great, is the complete simulation of a racing series. The same thing that made GTR2 successful at its time.
 
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.
It is a natural software development process, why would they start from scratch?
And what do you mean by "something less"?
 
FYI if you don't want to wait for RD: next "episode" is up on AC forums, this time about tyres.

Just read it, alot more information than I expected including rain effects etc.

I especially agreed with his comments about the real time tire apps out there sim racers use. They give alot of information Blancpain drivers do not have access to on track, so it was nice to read this coming from a developer.

"I think simracers have been going way too far with controlling every single aspect of their tyres. I see videos with tons of apps that show in real time surface temps, real time wear, real time blistering/graining… everything. We are all craving for the best possible simulation and then we use all of that stuff… we are borderline cheating to be honest. So I’d like to return to a more realistic situation where you get the info real teams get and that’s it.
You want to see how much your tyres are worn with precision? Go back to the pits and read the depth. You can’t have it in real time while driving.
You want surface temp? Sorry no luck. Core temp and pressure, maybe yes. Again go to pits and check. Same for blistering graining and so on… "
 

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