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.


Like what you see here at RaceDepartment? Don't forget to like, subscribe and follow us on social media!

 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'm finally starting to see what people love about rF2.

Yes I guess it took eye candy and more content to get some to drive it long enough to see why some people rave about it hehehe

Thing is from very first build it felt as good as it does now, seriously even without features came later like chassis flex etc

Whoever said rF2 does not have faults with tyres, physics and most other things ?

I never heard anyone of hundreds I online with ever say that
I think most haters think we fans think it is worldly realistic or something ? lol

We just think it is better then the alternatives, no more no less
No difference how all of us think about our favourite sim

But somehow rf2 lovers are different creatures to all the rest ? lol
 
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.

Now grab your G27 and enjoy the placebo effect!!!
 
erm....how can "The Official Blancpain GT series Game" not be as specific a license and game as those two...?

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.....

Moving to the Unreal engine, is no small task, particularly when it is imperative to ensure you retain enough performance to run on a wide range of hardware; and it is getting wider all the time, with VR, ever increasing resolution, etc. By focusing on this title first, with a narrower set of cars and tracks, they will gain experience and be able to refine their underlying technology, hopefully to the point where it becomes possible, in the next iteration, where they can focus on expanding the width and breadth of the content (cars, tracks, multi-player, liveries, etc.). Developers need to get paid, and hopefully the ROI on this title is sufficient to ensure Kunos is profitable and motivated to expand their titles.
 
Whoever said rF2 does not have faults with tyres, physics and most other things ?

I never heard anyone of hundreds I online with ever say that
I think most haters think we fans think it is worldly realistic or something ? lol

We just think it is better then the alternatives, no more no less
No difference how all of us think about our favourite sim

But somehow rf2 lovers are different creatures to all the rest ? lol

There are some people who do believe RF2 to be "worldly realistic" or "realistic".
I think RF2 really nails some cars and has the best foundation for a physics engine to date and is a cut above the competition especially regarding physics and AI, it's also not finished in the development department AFAIK, always a good thing.

I think the haters are misunderstanding most people who enjoy RF2. But haters gonna hate.
I know there is a subset of people who will never try or even give RF2 another thought simply because it's not exactly pushing the graphics envelope.

There's also a certain group of people who have dated knowledge from RF2's poor launch and need to read up just how far the simulation has come from those launch days.
 
I think youre insistent on perpetuating a myth that theres a "them and us" mentality over sims.

there isn't, we all have all/most of them id imagine and play through all of them in varying ways dependant on mood.

insisting there are "haters" of specific sims, or "fanbois" (sic) of others, in this environment, is just provocative in nature (intended, clearly) and toxic.

get over it.

I think ive seen RF2 mentioned more in this thread than ACC.......
 
I think youre insistent on perpetuating a myth that theres a "them and us" mentality over sims.

there isn't, we all have all/most of them id imagine and play through all of them in varying ways dependant on mood.

insisting there are "haters" of specific sims, or "fanbois" (sic) of others, in this environment, is just provocative in nature (intended, clearly) and toxic.

get over it.

I think ive seen RF2 mentioned more in this thread than ACC.......


Apart from generalizing me...Why are you so bothered what I think? I'm talking to the other guy lol why you want to keep derailing this thread about the he said she said BS is beyond me.
 
well firstly, don't be such a reactionary, I was more generalising the thread, not you, but very insular of you.

secondly, im really not that bothered what you think, but I do always find that a particularly funny thing people say when they offer up their opinion in a public forum then take Umbridge if someone makes a comment they don't like or disagree with. this isn't particularly a private conversation between two people either, so finding it odd someone else chimes in is....odd, also, he said she said, implies theres an element of doubt as to who said what....its clearly all in black and white here so.....

and finally, this thread was derailed a long, long time before I turned up


but by all means just disagree with things you don't like, that's "kewl"
 
well firstly, don't be such a reactionary, I was more generalising the thread, not you, but very insular of you.

secondly, im really not that bothered what you think, but I do always find that a particularly funny thing people say when they offer up their opinion in a public forum then take Umbridge if someone makes a comment they don't like or disagree with. this isn't particularly a private conversation between two people either, so finding it odd someone else chimes in is....odd, also, he said she said, implies theres an element of doubt as to who said what....its clearly all in black and white here so.....

and finally, this thread was derailed a long, long time before I turned up

Yes I'm sure you were'nt talking to me when you wrote "I think youre insistent on perpetuating a myth that theres a "them and us" mentality over sims." that tied with(in the same post no doubt) "insisting there are "haters" of specific sims, or "fanbois" (sic) of others, in this environment, is just provocative in nature (intended, clearly) and toxic.

get over it.
" I mean who else exactly were you talking to or implying with such a specific statement? yourself? ;) Knock it off, but incase you were talking to someone else, specifically. I'll end it here because I really don't have time to argue about the nonsensical.. but Maybe you should quote them mate to avoid creating all this confusion :)

Edit: If I were to laugh at something or make a cheap save-face joke like you constantly do, It is rather Funny your use the of the disagree is out of spite, recklessly so and even funnier how you talk about it as if it's something you'd never do. that's damn hypocritical right there darnit! :D
 
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perhaps that's why I didn't quote anyone in particular...

im not confused. I doubt im not the only one

Highlight in bold all you want chap.


Edit hahahah with the disagreeing again.....this guy, I could write "this is racedepartment" and youd disagree...
 
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Also most of the Pc's won't be able to maintain at least 60fps with the new graphics eye candy!

I have an FX-8350 with a GTX 660 and i can get 60 FPS in AC with some adjustments that don't require butchering the graphics completely (same with rFactor 2, which even with the Directx 11 update is still way heavier than it should). I even have reshade on because i can't stand the filter of the basic game (ACC appears to be even worst in that respect).

In ACC, i get around 25 FPS with everything on "epic", and 40 on everything on high.

Obviously an upgrade is in order but i think probably getting a new mid range card would suffice (was thinking of an RX 580 because i have a FreeSync monitor).

Either way, we are talking about ancient hardware here but it was still viable until now. Games are not as heavy as they used to be, last game that was made to tax available hardware to the fullest was Crysis 1. Console limitation and the advent of 4k and 100+ FPS monitors means mid-range hardware is good enough for 60 FPS and 1080p in most cases.
 
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."

But they still haven't figured out how to get rid of shadow or artifact pop ups. I got excited when i saw an option for drawing distance in ACC, but nope, that stuff is still there.

I really have a problem with how modern games look in general. None of them look natural and there's too many effects that don't even make sense, like motion blur or depth of field.
 

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