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[DiRT 4] Constructive feedback on the subject of car-feel and physics: The Ultimate Thread

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gheeD said:
that would be in line with what ive noticed aswell. Its always caused by one of the tires not having contact with the ground
And since the stages are so off camber/bumpy/rough one of the wheels are oftrn hanging freely in the air. 

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bogani said:
Isn't it the LSD's job to feed the outer wheel with most of the available tourque when the inner wheel lifts? If it was a completely open standard  diff the tourqe would we equal between the wheels thus not giving the wheel with traction enough tourqe while the lifted wheel would accelerate freely.

So are the diffs working correctly?
No.

An LSD does pretty much as you say, but depending on the type of diff, generally transmits a percentage of the torque to the outer wheel.  If you lift a wheel, the available torque becomes zero and the torque transmitted to the opposing wheel is a percentage of zero ie zero!

https://youtu.be/H3FTG0RVBJU

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For your differential explanation needs:
https://www.youtube.com/watch?v=ujsxq9WBllU

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hawku0 said:
gheeD said:
I am talking about both wales and australia, but my experience with finnish roads is that regardless of the car you want to have the front end as close to the inside as possible since the corners simply are cambered towards the inside and you can carry lot more speed by using the natural camber to rotate the car around a corner. In real life this is obviously a balancing act as if you really put the front tyres into the ditch on the inside there can be rocks and other stuff that can blow your tyre or worse if you are not careful. 

The foresty part of wales / and australia is biggest problem imo, the big cushions/banks on side of the road where you might put your tire just sort of accelerate your car too much into a spin, sort of same behaviour as a snow bank sucking you in (snowbank really decelerates the front end of the car that causes the spin and then sucks you in, but here it doesnt actually suck you in, it just somehow causes the rear end to snap) I think this is kind of related to same issues i find with the tyres lifting when you come to a corner with lots of roughness and different cambers, it sort of throws the car totally of whack. This wouldnt be such a huge issue i feel if the track design wasnt so extreme, everything is very rutted and rough and causes tyres to lift all the time and when you push the car hard it causes these behaviours to manifest often.
I made a video of the problem:
https://youtu.be/DeiYI6HNKn4

Analysis and data:
https://docs.google.com/spreadsheets/d/1JU_s33ms0UQJeoQLv5pFCozBr0QTHyYhXcMOIfegvoI/pubhtml

It seems that the inner rear wheel lifts off the ground when you hit the side of the road. When the inner wheel is off the ground, it doesn't have any grip and will suddenly accelerate.
Maybe this happens with a firm roll bar setting, because the grass seems to be a bit higher/bumpier? Causing the inside to go up with the outside? Then it spins up and launches the car into a spin?

@gheeD: So I took the time and watched some footage again and what I found was, that indeed, when only one wheel catches grass like this, then that doesn't mean the car will spin. On the other hand, when a RWD just continues it's slide far enough, that both rear wheels catch the grass, it's game over.

Few examples for the ones interested (also shows how icy grass can be):
https://youtu.be/xnlIYzfHg4w
One tire: 0:15, 8:28, 9:17
Two tires: 3:20, 3:42, (6:10), 10:22, (10:52)


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Dytut said:
For your differential explanation needs:
https://www.youtube.com/watch?v=ujsxq9WBllU
With that in mind, doesn't that mean, that when one wheel looses traction on grass, the torque from the combined wheels against the motorshaft drops in an instant, what leads to an acceleration and tightens the LSD more than its already is? Then this leads to a power increase on the inner wheel that kicks the rear into a spin?

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btw check this skoda r5 behaviour on wet grass trying to catch a slide. imagine how it would be if that was in dirt 4. 

clip at 4:35
https://youtu.be/6gGQAcuS4vA

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gheeD said:
btw check this skoda r5 behaviour on wet grass trying to catch a slide. imagine how it would be if that was in dirt 4.
Yes, that looks different indeed! But keep in mind this is an AWD.

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gheeD said:
clip at 4:35
definitely different behaviour, although it should be noted that this vehicle in question has a blown rear tire.

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ah i didnt even notice that. But yeah in real life there are so many variables to these conditions that hard to simply state what a car should do or not when a tyre goes on the grass. Its just my feeling that the current behaviour in such situations is greatly exaggerated and ruins the enjoyment. one moment you battle getting a rwd car to turn in a corner next time you get surprised by the rear snapping on you and going sideways. 

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It totally is extremely difficult to determine ;). Looking at videos it might shows one way or the other and everyone has different expectations in different situations in the first place. So yeah, I guess the truth lays somewhere in between doesn't it? And yes, the RWDs in Dirt4 are already snappy from the get-go, so I really think this may be the cause of things here or simply overshadows this effect.

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I haven't had much time to test anything recently except playing for a bit last night so you guys are doing God's work. Keep it up and i'll try and contribute soon!

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fab1701 said:
hawku0 said:
gheeD said:
I am talking about both wales and australia, but my experience with finnish roads is that regardless of the car you want to have the front end as close to the inside as possible since the corners simply are cambered towards the inside and you can carry lot more speed by using the natural camber to rotate the car around a corner. In real life this is obviously a balancing act as if you really put the front tyres into the ditch on the inside there can be rocks and other stuff that can blow your tyre or worse if you are not careful. 

The foresty part of wales / and australia is biggest problem imo, the big cushions/banks on side of the road where you might put your tire just sort of accelerate your car too much into a spin, sort of same behaviour as a snow bank sucking you in (snowbank really decelerates the front end of the car that causes the spin and then sucks you in, but here it doesnt actually suck you in, it just somehow causes the rear end to snap) I think this is kind of related to same issues i find with the tyres lifting when you come to a corner with lots of roughness and different cambers, it sort of throws the car totally of whack. This wouldnt be such a huge issue i feel if the track design wasnt so extreme, everything is very rutted and rough and causes tyres to lift all the time and when you push the car hard it causes these behaviours to manifest often.
I made a video of the problem:
https://youtu.be/DeiYI6HNKn4

Analysis and data:
https://docs.google.com/spreadsheets/d/1JU_s33ms0UQJeoQLv5pFCozBr0QTHyYhXcMOIfegvoI/pubhtml

It seems that the inner rear wheel lifts off the ground when you hit the side of the road. When the inner wheel is off the ground, it doesn't have any grip and will suddenly accelerate.
Maybe this happens with a firm roll bar setting, because the grass seems to be a bit higher/bumpier? Causing the inside to go up with the outside? Then it spins up and launches the car into a spin?

@gheeD: So I took the time and watched some footage again and what I found was, that indeed, when only one wheel catches grass like this, then that doesn't mean the car will spin. On the other hand, when a RWD just continues it's slide far enough, that both rear wheels catch the grass, it's game over.

Few examples for the ones interested (also shows how icy grass can be):
https://youtu.be/xnlIYzfHg4w
One tire: 0:15, 8:28, 9:17
Two tires: 3:20, 3:42, (6:10), 10:22, (10:52)


I have tested with different ARB, spring and bump/rebound settings, but i can't get rid of that problem.

Grass isn't that slippery in Dirt 4. You can easily climb a 45 degree hill with an AWD car when you go off the road in Wales.
That snap oversteer doesn't happen when there is no bump in between the road and the grass.

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wish she could have said whats being looked at and to what extent...................this mystery and short worded-ness is kiling me lol !

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We are spending a lot of our time analysing the data coming from the game to get a better understanding of what (if anything) we can do about things.
I think that the "(if anything)" part is the most unsettling and unnecessary part of the road book.

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To the wheels off the road issue. I have found if you make the springs soft, slow bump front firm, fast bump middle, rear slow bump -1 or -2, fast bump middle, the important part here iv found by making the rebound soft it really frees the suspesion movement which seem to no longer upset the car, was driving Fitzroy in 205 gti and was able to cut corners without an upsets. Tried this on the Hyundai as well. Set tender springs both a few ticks right,  and bump divisions to 0, 

From what i can tell is the suspension seems to react very inconsistent with stiffer dampers in most cars causing some really abrupt weight transfer. I have watched a lot of replays of RL rally cars and they almost always seem to have super plush suspension which makes total sense easier to control car over rough terrain with soft settings. It looks from my replays and the feel of the car as though with softer rebound the car shifts its weight more progressively. Easier drifts as well.Just my .2.

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Thing about 1 wheel on slippery grass if we can go back to the relationship the suspension has with the other 3 wheels of the car. Stiffer suspension will be much less sensitive to this. Hence the reason why i started running higher bump.

Being bumpy surface people tend to think "okay obviously i need softer suspension to ride the bumps and promote oversteer/slide". This increases grip yes, but it effects the response the other 3 wheels will have on weight transfer and load. In reality you go with as much responsiveness (stiffness on the suspension as you can) as it allows you to run lower rideheight and distributes the overall grip and weight transfer of the car much more predictably and evenly.

In wet weather because theres allot less grip and traction available obviously you then setup your car to be softer on the suspension to makeup for the overall lack of grip.

For those that requested. here is the Mitsubishi  EvoX setup. I should also stress I added 2 spare tyres in the extra options for this car setup. I strongly recommend bringing 2 spare tyres with this setup.
http://imgur.com/a/It7cG
Adding 2 spare tyres will put more weight onto the rear tyres helping gain traction and making the rear tyres more responsive mid corner during slides.

@qmass , @chukonu
Thanks for the screenshots.
I tried your setup. Car behaviour is better (still feels FWD-ish), but I had to tame the brakes a lot... couldn't use your setting at all.

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Mystx24 said:
To the wheels off the road issue. I have found if you make the springs soft, slow bump front firm, fast bump middle, rear slow bump -1 or -2, fast bump middle, the important part here iv found by making the rebound soft it really frees the suspesion movement which seem to no longer upset the car, was driving Fitzroy in 205 gti and was able to cut corners without an upsets. Tried this on the Hyundai as well. Set tender springs both a few ticks right,  and bump divisions to 0, 

From what i can tell is the suspension seems to react very inconsistent with stiffer dampers in most cars causing some really abrupt weight transfer. I have watched a lot of replays of RL rally cars and they almost always seem to have super plush suspension which makes total sense easier to control car over rough terrain with soft settings. It looks from my replays and the feel of the car as though with softer rebound the car shifts its weight more progressively. Easier drifts as well.Just my .2.
Thanks to you and the many others who are exploring setups to see if we can get some believable handling back. However, if we were able to get cars to behave normally through setups, aren't we just putting ourselves at a disadvantage? In D4 it seems the fastest way to take a turn is to come in too hot, flick hard into the turn to kick the back end out, and then using the hand of God acceleration to regain straightline traction before the car flies off the outside of the turn.

Compare that to correctly setting up entry speed, weight transfer and trajectory, throwing the car into a controlled slide and smoothly sailing out of the corner with throttle/brake as necessary. It seems to me this would be WAY slower than the way things are now and that if we find setups that allow us to do this it will just make us slower overall.

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hawku0 said
I have tested with different ARB, spring and bump/rebound settings, but i can't get rid of that problem.

Grass isn't that slippery in Dirt 4. You can easily climb a 45 degree hill with an AWD car when you go off the road in Wales.
That snap oversteer doesn't happen when there is no bump in between the road and the grass.
Speaking of springs and bumps, I was watching the latest footage from Poland WRC. It is always amazing to see the suspension at work. It makes the car look like it floates or hovers steadily above ground, while the suspension absorbs all and every bumps and banks.

https://youtu.be/2eYJQSKHGVA

I tried to reproduce the i20 R5 to look and feel like in those videos (Fitzroy), but I am not able to get there. It looks like the suspension in D4 is often unable to cope with all the bumps and the tyres are not really constantly in contact with the surface as in those videos. Is anyone able to achieve such great suspension work?


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Mystx24 said:
To the wheels off the road issue. I have found if you make the springs soft, slow bump front firm, fast bump middle, rear slow bump -1 or -2, fast bump middle, the important part here iv found by making the rebound soft it really frees the suspesion movement which seem to no longer upset the car, was driving Fitzroy in 205 gti and was able to cut corners without an upsets. Tried this on the Hyundai as well. Set tender springs both a few ticks right,  and bump divisions to 0, 

From what i can tell is the suspension seems to react very inconsistent with stiffer dampers in most cars causing some really abrupt weight transfer. I have watched a lot of replays of RL rally cars and they almost always seem to have super plush suspension which makes total sense easier to control car over rough terrain with soft settings. It looks from my replays and the feel of the car as though with softer rebound the car shifts its weight more progressively. Easier drifts as well.Just my .2.
Thanks to you and the many others who are exploring setups to see if we can get some believable handling back. However, if we were able to get cars to behave normally through setups, aren't we just putting ourselves at a disadvantage? In D4 it seems the fastest way to take a turn is to come in too hot, flick hard into the turn to kick the back end out, and then using the hand of God acceleration to regain straightline traction before the car flies off the outside of the turn.

Compare that to correctly setting up entry speed, weight transfer and trajectory, throwing the car into a controlled slide and smoothly sailing out of the corner with throttle/brake as necessary. It seems to me this would be WAY slower than the way things are now and that if we find setups that allow us to do this it will just make us slower overall.
I can say for sure for myself that by doing this just the car being less twitchy and more in control my confidence sky rocketed and i was starting to really be able to push. Before id push but with not great setup i would find my self second guessing what would happen when i did toss the car. I am still in heavy test mode.

I have a real suspicion that the grip/physics are not all that off. But the abysmal defaults are really to blame. And being as alot of people either dont understand suspension or dont care to well those defaults just dont cut it. Anrd thanks. Ill keep tweaking cars. Iv got most rwd feeling pretty ok but have not tried new setup with them.

I would like to add as of this setup atm i start 0 camber and toe all around.  Change suspension first then add little nibbles of camber and toe as needed

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hawku0 said
I have tested with different ARB, spring and bump/rebound settings, but i can't get rid of that problem.

Grass isn't that slippery in Dirt 4. You can easily climb a 45 degree hill with an AWD car when you go off the road in Wales.
That snap oversteer doesn't happen when there is no bump in between the road and the grass.
Speaking of springs and bumps, I was watching the latest footage from Poland WRC. It is always amazing to see the suspension at work. It makes the car look like it floates or hovers steadily above ground, while the suspension absorbs all and every bumps and banks.

https://youtu.be/2eYJQSKHGVA

I tried to reproduce the i20 R5 to look and feel like in those videos (Fitzroy), but I am not able to get there. It looks like the suspension in D4 is often unable to cope with all the bumps and the tyres are not really constantly in contact with the surface as in those videos. Is anyone able to achieve such great suspension work?


Try my setup its super plush this game requires it. The roads are so rough. It is do able i am no longer being pulled by the off main road driving. Super smooth and fast now. 

Ps: i can make a vid if needed once home from work. I want people to like this game it has been a real tuning experience so far. My tuning experience prior to this is tuning 10th scale short course trucks. Had to learn how to adjust to be fast

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I will try it.

While we are all talking about Difs, torque, tyres and forces, has anyone thought about how dense the physical model of the sureface is?
Afaik, there is always a physical and a visual model with regards to tyres and surface. The physical mesh is more dense or has a higher resolution for less performance impact.

The reason I am raising this point is, in circuit racing sims, the road is way more flat and the pysical mesh is probably very dense when needed (little bumps and undulations). For instance, I think iracing has one of the highest resolution for their circuits.

Now imagine a surface like Fitzroy or Wales. I guess the physical resolution is not as high, as in most racing games. And now we have a very bumpy surface with an even more bumpy resolution on the bumps itself. Wouldn't this add to less tyre contact patch and result in more strange car behaviour when it comes to diff and torque?
I could even add another factor into the equation, the physics tick rate. We don't know much about the DiRT physics model, but the reason for strange car behaviour can be really deeply hidden.

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I will try it.

While we are all talking about Difs, torque, tyres and forces, has anyone thought about how dense the physical model of the sureface is?
Afaik, there is always a physical and a visual model with regards to tyres and surface. The physical mesh is more dense or has a higher resolution for less performance impact.

The reason I am raising this point is, in circuit racing sims, the road is way more flat and the pysical mesh is probably very dense when needed (little bumps and undulations). For instance, I think iracing has one of the highest resolution for their circuits.

Now imagine a surface like Fitzroy or Wales. I guess the physical resolution is not as high, as in most racing games. And now we have a very bumpy surface with an even more bumpy resolution on the bumps itself. Wouldn't this add to less tyre contact patch and result in more strange car behaviour when it comes to diff and torque?
I could even add another factor into the equation, the physics tick rate. We don't know much about the DiRT physics model, but the reason for strange car behaviour can be really deeply hidden.
You may be on to something i think the roads are much much more rough then they appear also especially Fitzroy almost all corners are off camber. Im curious as well since RX and rally seem to have different tyre models are we just really feeling the mayb incomplete rally tire. And to your point if roads are more or less really bumpy then bad suspension/diff setup is going to be exaggerated.

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Mystx24 said:
hawku0 said
I have tested with different ARB, spring and bump/rebound settings, but i can't get rid of that problem.

Grass isn't that slippery in Dirt 4. You can easily climb a 45 degree hill with an AWD car when you go off the road in Wales.
That snap oversteer doesn't happen when there is no bump in between the road and the grass.
Speaking of springs and bumps, I was watching the latest footage from Poland WRC. It is always amazing to see the suspension at work. It makes the car look like it floates or hovers steadily above ground, while the suspension absorbs all and every bumps and banks.

https://youtu.be/2eYJQSKHGVA

I tried to reproduce the i20 R5 to look and feel like in those videos (Fitzroy), but I am not able to get there. It looks like the suspension in D4 is often unable to cope with all the bumps and the tyres are not really constantly in contact with the surface as in those videos. Is anyone able to achieve such great suspension work?


Try my setup its super plush this game requires it. The roads are so rough. It is do able i am no longer being pulled by the off main road driving. Super smooth and fast now. 

Ps: i can make a vid if needed once home from work. I want people to like this game it has been a real tuning experience so far. My tuning experience prior to this is tuning 10th scale short course trucks. Had to learn how to adjust to be fast
I would really appreciate a vid. Thanks for offering. I have been rage quitting this game after an hour since June 6th. Everything just feels so off. I have managed to improve some things through setups thanks to my own experimentation as well as pointers in this thread but it's still very frustrating.

Before D4 I was easily jumping between DiRT Rally, Loeb Rally EVO and WRC 6 as all three of those titles have something in common: intuitive handling models. SLRE has the best physics IMHO. DR is also great although a bit too easy to slide and correct. WRC 6 is a huge improvement over the pathetic 5 and the handling model is competent, intuitive and believable although it does have quite a bit of simcade in it. What I mean is, with those three titles, you only need a couple minutes to adapt to each game's quirks because the underlying handling models are similar. You don't have to learn how to drive again when swapping between them.

The last couple evenings I have spent several hours with D4 trophy hunting on the PS4 Pro and could feel myself starting to adapt. The problem is I feel I am adapting to bad habits. I don't want to have to re-learn how to drive a virtual rally car for one single game, especially since I still play lots of SLRE and WRC 6 and once a week I jump into DR for my league events.

I am not a very fast guy, about top 25% on gravel and top 10% on asphalt, but here are some of my runs in SLRE, WRC 6 and D4 for comparison. The SLRE and WRC 6 replays just look more believable to me (handling-wise, not graphics-wise LOL). I am not a professional racer but have been playing racing games since the late nineties. I have done a lot of karting and when I had a 2000 Impreza I put 60,000km on it in South America. Needless to say I never pushed it to the limit but throughout Argentina, Brazil, Uruguay, Chile and Bolivia I had plenty of opportunities to do some light-hearted rally-style turns on a variety of loose surfaces. And as a motorsports freak in general, I think most of us on this board can feel when physics are right or if there is something off, unlike Headlong who insists that if you are not Sébastien Loeb you are unqualified to critique a rally game.

https://youtu.be/sv0YPoJvT44

https://youtu.be/EVy7l7jh-4I

https://youtu.be/YvESHKHqgQA

I am Simulation with no assists and Logitech G29 just for the record. If anyone sees any fundamental flaws in my driving style (besides being afraid to be on the limit LOL) that could be preventing me from getting a better experience from D4 I'm all ears.

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