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Kunos Simulazioni - Assetto Corsa
(8883 posts, started )
This is how SIMBIN sees a car (with forces as relative to CoG):



LFS additionally sees also forces on these:


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(Wenom) DELETED by Wenom
The name you're looking for is "ray casting wheel model".

And no, it's not box physics. Box physics is one single mass point with no separate forces from each wheel. It's sometimes referred to as "center pivot physics". With the exception of Mario Kart clones this approach has been dead for years. Even the most arcade car games use ray casting now.

NFS2 is a box physics title. Anything ISI is not.


The wheels in ISI sims have moment of inertia calculation linked correctly to the drive line components. It's no worse than LFS/AC in this regard and the angular velocity you see is not just a graphical representation. I know this is LFS forum and people do ISI bashing with a passion but some times it's going a bit too far.
LFS had tire flex while other sims didn't, and the force feedback was simulated instead of using canned effects, but I don't think that modern sims are lacking any of that, so now they are all (almost) even in the physics field.
LFS had visual tire flex when others didn't. All car sims have had flex but not visual flex.
Quote from AndRand :
Quote from Hyperactive :Anyways, it is a simple math problem.
http://en.wikipedia.org/wiki/List_of_moments_of_inertia
For box you have


Is whole AC physics the SIMBIN one box style?
Or more close to LFS mostly concerned with tire-ground patch physics?

That box is just an illustration of how ac handles the car body inertias. Tires have their own weight and rotational inertias as well but it doesn't go as deep and complex as rf where you can have inertia values for all parts I think.

The problem with ac is that instead of allowing users to directly write the car body inertias in the files they use this strange box which is used to roughly describe the car dimensions for the inertia calculations. A box itself is easy to solve and convert into inertias but there is some kind of multiplier or set of multipliers that makes it really difficult to use the real inertia values if you have those.

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This will be getting released today too:
Quote from Keling :The wheels in ISI sims have moment of inertia calculation linked correctly to the drive line components. It's no worse than LFS/AC in this regard and the angular velocity you see is not just a graphical representation. I know this is LFS forum and people do ISI bashing with a passion but some times it's going a bit too far.

It is not bashing - it is asking: when I buy AC will I go back to game like RACE07 or proper sim?

LFS is known for representing as separate objects all parts from tire contact patch to suspension mount (mounted to rigid body - that means CoG with given arm): tire elasticity, wheel inertia, spring/dumper units, wishbones, steering rods, antiroll bars.
The way to simplify is to make a combo object transferring forces from ground to car body. Of course the more parts are simulated - the better, becuase all have their operating angles and force transfer (especially seen with damage simulated - in AC I could see only wheels being jammed). So instead of results from simulation of one part being taken as inputs of another to give overall effect, the tweaking of such combo with parameters of each part is then "the state of the art" - simplified formulas for combo giving simplified results.
All modern physics engines can do very good job if you put in the correct numbers. As far as suspension design goes lfs is probably the least advanced of them all. I remember reading something about how lfs suspensions only work in 2d but I don't remember what was it exactly. I think lfs suspension supports stuff like antidives and kingpin offsets along with complex bumpsteers and caster changes so maybe I'm just imagining things.

As for box physics you can make 3 wheel cars in ac and it works pretty much without any issues. While ac doesn't support 3 wheeled cars and asymmetric suspensions it still allows asymmetric cars to be created as long as the suspension arms are identical on both sides. I'd imagine motorbikes is possible too although I don't know if the rotational inertia of the tires is modelled in ac. But we all remember nkbike Wink.
Yes, LFS suspension is only 2D.

If there's anything fancy with LFS's suspension, it supports beam axle.

Quote from AndRand :It is not bashing - it is asking: when I buy AC will I go back to game like RACE07 or proper sim?

LFS is known for representing as separate objects all parts from tire contact patch to suspension mount (mounted to rigid body - that means CoG with given arm): tire elasticity, wheel inertia, spring/dumper units, wishbones, steering rods, antiroll bars.
The way to simplify is to make a combo object transferring forces from ground to car body. Of course the more parts are simulated - the better, becuase all have their operating angles and force transfer (especially seen with damage simulated - in AC I could see only wheels being jammed). So instead of results from simulation of one part being taken as inputs of another to give overall effect, the tweaking of such combo with parameters of each part is then "the state of the art" - simplified formulas for combo giving simplified results.

Sorry for being harsh with my words.

For suspension, we're looking at rigid bodies with only one DoF per corner here, so combined or not they are effectively the same. Most of the forces will go straight though the rigid structure. The only difference is probably inertia handling on those suspension parts, which isn't much.

The elastic tire model in LFS was such a brilliant creation it made Pacejka-based everything else look obsolete. rF1 was way behind it in this aspect, but the rigid parts were more or less the same.

If one day we can have elastic drive line simulation, modeling each component separately would make a huge difference at least in theory.


Not sure about "only see wheels being jammed" in AC. The current implementation of damage in AC is so simple it's probably not acting on each separate component.
Quote from Hyperactive :I think lfs suspension supports stuff like antidives and kingpin offsets along with complex bumpsteers and caster changes so maybe I'm just imagining things.

Current LFS doesn't seem to support anti-dive, as reported in the 2009 tyre physics progress report.

Quote from Progress report dec 2009 :In real life, the suspension geometry is designed to produce an anti-dive effect under braking and anti-squat under acceleration. This has until now been absent from the LFS suspension systems, but now looks like an important development to support the realistic setups.

Quote from Hyperactive :The newest version of the jaguar is out: http://www10.zippyshare.com/v/rr2X4UBw/file.html

Already praised you on AC forums, can't add anything more, awesome stuff!

Anyy chance of adding some auto lift on upshifts? I don't like lifting cause i think it hurts these already fragile logitech pedals lifting and pressing the pedals so many times during the lap, and i'm trying so hard not to have them spiking on me. Right now it damages the engine when not lifting.
You could just turn damage off. The engine damage is really slow at the limiter so you can easily do many laps before your engine goes kaput. Auto lift.. no boris Smile
Boris the number of times pressing your pedal is minimal dofference. Just avoid getting dust and hair inside them or pressing really hard.
Time for new adventures:

Probably out before "new" westhill...
The roll cage dimensions needs a bit of work...
I think it needs lots of work overall Smile
and I just wanted to ask you if you could help me with my suspension...

... anyone on here interested in building a base setup for my 24h Special? I can't really get to grips with it
Quote from ACCAkut :and I just wanted to ask you if you could help me with my suspension...

... anyone on here interested in building a base setup for my 24h Special? I can't really get to grips with it

hold on, 24H special?
nah my Alzen Porsche. It ran in a class called 24h Special

Yolo: http://www.assettocorsa.net/forum/index.php?threads/lx8.20506/

Quote from ACCAkut :and I just wanted to ask you if you could help me with my suspension...

... anyone on here interested in building a base setup for my 24h Special? I can't really get to grips with it

I'm happy to occasionally drive the car and give you feedback but sadly it is not exactly my type of car so I'm not really interested about it. If you have questions I'm happy to answer but making the suspension for the car would require just too much time spent finding data and calculating stuff. What's the problem?
since I deleted the setup.ini the car is more or less undriveable, no grip at all at the front axle (that is with the official spring rates I got) So its (I guess) a matter of setting up dampers and rollbars.
Did you save your setup.ini contents before you deleted it? If yes then just go through each setup setting to see where the spring, damper or some else value goes outside the setup.ini range and then use the min or max value of that setting (from setup.ini) as placeholder. For example if your front wheelrate was 120k and your setup.ini range was 60k-90k then use 90k. Similarly if your diff coast was 35 in the drivetrain.ini but your setup.ini had it limited to 50-80 then use 50.

Have you calculated the spring frequencies?
Suzuka v1.1

3D grass
Improoved vegetation
3D external landscape
Track surfaces and physics improovements (Sand, Grass, Carpet, Kerbs, and Invalid Track areas)
Track Map functional
Track Cameras improoved
Added colisions with track objects (Except ‘cones’)
Pole and Sun position reorientated
Minor textures changes and improovements (Pit building, Terrain and Trees)
3D Road mesh improoved for smoother track surface

https://malagoligarage.wordpre ... suzuka-circuit-v-1-0-wip/

Edit:
Wow on that site is also updated Brno track, with 3d grass and shit.., must check it out


Kunos Simulazioni - Assetto Corsa
(8883 posts, started )
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