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

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bogani said:
This game is frustratingly inconsistent. I took the Fiesta R5 to the daily Australian stage that had the atrocious Evo VI, and I've found a really great setup for it. Driving this stage with the R5 just feels great. The car moves around pretty much exactly like I want it to. If the lateral/longitudal grip was much less it would feel pretty bad.

Btw, this was the BEST Australian stage I've driven so far. Not much repeating of tiles. It was really great.

https://youtu.be/DGPcYCfZFlU
What setup you use !?default !?
Nope, not default, but nothing crazy. If you use steam I can share the setup if you add me. bogani85

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SamRWD said:
battfinkz said:
SamRWD. did he use abs for the braking distance test?. If not, how did he regulate maximum braking force without locking the wheels up? Or did he just 100% brake?
AFAIK sim, all assists off. you can make that test yourself (I did many pages back, I even posted a video here somewhere). He tested on a gamepad and wheel. No need to worry about locking the wheels- it is not this kind of game apparently:

https://youtu.be/pCW6WVLY1uw

https://www.youtube.com/watch?v=V3dV4CuR04g

bogani said:
This game is frustratingly inconsistent. I took the Fiesta R5 to the daily Australian stage that had the atrocious Evo VI, and I've found a really great setup for it. Driving this stage with the R5 just feels great. The car moves around pretty much exactly like I want it to. If the lateral/longitudal grip was much less it would feel pretty bad.

Btw, this was the BEST Australian stage I've driven so far. Not much repeating of tiles. It was really great.

https://youtu.be/DGPcYCfZFlU
Would you mind sharing your Fiesta R5 setup? I gave up on that car because I couldn't make it drive the way I like.
You on PC Sam?

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SamRWD said:
@bogani

Yes, PC reporting in ;) 
  • Body is 10 characters too short.
Add me on steam. I'll share the setup. I'll share the stage as well as it was really nice.

bogani85

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ill add you ,thanks Bogani , appreciate it!
If only it was easy to share setups... Anyone know how to do it?

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i cant get why the f1 2016 set up system wasnt used.its so simple its part of codies work and is amazing.

guy sets top time copy set up.done.set ups can be a massive difference as we already know.its very important.

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bogani said:
ill add you ,thanks Bogani , appreciate it!
If only it was easy to share setups... Anyone know how to do it?
Screenshots are all I can think of. BTW I tried adding you, searching for "bogani85" returned no results :( Maybe you could add me? "SamRWD"is my account name.

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dgeesi0 said:
i cant get why the f1 2016 set up system wasnt used.its so simple its part of codies work and is amazing.

guy sets top time copy set up.done.set ups can be a massive difference as we already know.its very important.
Well that's just it, car setups (in RL) are an x-factor to the sport so...if you share your setups with your competition, you potentially lose your edge =D

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https://www.youtube.com/watch?v=hCnLeOPSv9c

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.

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SamRWD said:

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
Great find! This shows that the physics in D4 are correct in this aspect, but maybe exaggerated (at least for some cars). This doesn't necessarily lead to tyre parameters though. Possibly, yes, but at the very basic this only shows, that the forces that come into play, the cars lateral movement energy and the resistance against it from the tires, may be off balance ;).

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fab1701 said:
SamRWD said:

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
Great find! This shows that the physics in D4 are correct in this aspect, but maybe exaggerated (at least for some cars). This doesn't necessarily lead to tyre parameters though. Possibly, yes, but at the very basic this only shows, that the forces that come into play, the cars lateral movement energy and the resistance against it from the tires, may be off balance ;).
Yes, you are right to some degree. However please note how wheels have no problem spinning in powerslide even if weight transfer is barely used- that means forward grip is even more exaggerated since even R5 cars manage to do fine in that regard (later half of video below):

https://youtu.be/IsK9CA5BPMg

We could brainstorm if it is not a matter of lack of engine power, however that wouldn't explain too short braking distances.

On top of that I wouldn't explain this kind of missbehavior of physics by trying to justify it with extreme examples from real life. We would need for the parameters to get sorted, and only then after some testing we can say if it is indeed just parameters.

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SamRWD said:

We could brainstorm if it is not a matter of lack of engine power, however that wouldn't explain too short braking distances.
That one just got me thinking...

Well let's pretend the grip gets lowered. This would help with the rear and the braking distance on gravel would increase. But then, because of less grip, the forward thrust would decrease even more. Now this seems wrong to me.
But there is a difference between braking and accelerating on gravel: Thrown material. Does anybody know how much thrust is created by simply the dirt that gets thrown away by a spinning tire? I bet this can be calculated to a degree. Also, how easy is it that a dirt-pile simply gets shredded away? Maybe thats something that needs to be considered.
EDIT: well i guess the extra-thrust will be minimal, but the tires digging in the ground should find additional grip somewhere down there ;).

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fab1701 said:
SamRWD said:

We could brainstorm if it is not a matter of lack of engine power, however that wouldn't explain too short braking distances.
That one just got me thinking...

Well let's pretend the grip gets lowered. This would help with the rear and the braking distance on gravel would increase. But then, because of less grip, the forward thrust would decrease even more. Now this seems wrong to me.
That would definitely be wrong. A lot of what people perceive to be issues with the physics are not issues but rather perceptions stemming from the fact that loose surfaces are now simulated properly. If people want a rally sim that doesn't simulate this and allows the cars to float freely on top of the surface they can play other sims. 


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SamRWD said:
https://www.youtube.com/watch?v=hCnLeOPSv9c

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
you cant see the difference ? i can go set world records on any track with the cars and you cant see the difference i can within seconds of that video playing.the cars dont react the same.they react yes not the same.

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dgeesi0 said:
SamRWD said:
https://www.youtube.com/watch?v=hCnLeOPSv9c

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
you cant see the difference ? i can go set world records on any track with the cars and you cant see the difference i can within seconds of that video playing.the cars dont react the same.they react yes not the same.
I think all he's saying with posting that video is the cars in D4 react like they hit some kind of embankment/dirt mound forcing the rear to stop sliding like some of them did in the video, but in D4 you are still on the road and it happens anyways.  Any of the other clips yes you can instantly see the difference how they can hold a powerslide through the corners, even over deep ruts.  You simply cannot do that in D4 in rally, no matter how crazy the setup or car you choose. 


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fab1701 said:
SamRWD said:

We could brainstorm if it is not a matter of lack of engine power, however that wouldn't explain too short braking distances.
That one just got me thinking...

Well let's pretend the grip gets lowered. This would help with the rear and the braking distance on gravel would increase. But then, because of less grip, the forward thrust would decrease even more. Now this seems wrong to me.
But there is a difference between braking and accelerating on gravel: Thrown material. Does anybody know how much thrust is created by simply the dirt that gets thrown away by a spinning tire? I bet this can be calculated to a degree. Also, how easy is it that a dirt-pile simply gets shredded away? Maybe thats something that needs to be considered.
EDIT: well i guess the extra-thrust will be minimal, but the tires digging in the ground should find additional grip somewhere down there ;).
There should be different friction coefficients for static friction and kinetic friction. When the tire isn't slipping, the friction values should be close to static friction values, which can be 30-60% higher than kinetic friction values.

In Dirt 4 it seems that there are same friction values in every situation or the difference is very minimal. That leads to that the friction values have to be higher to car to feel stable when tires aren't slipping, but it causes problems when the tires are slipping.

You can test the difference between static and kinetic longitudinal friction by trying to threshold brake on tarmac. I can't stop the car faster by threshold braking in Dirt 4, but maybe someone could make a video where they threshold brake and the car stops in less than 1.8 seconds from 100 to 0 km/h?
Currently the full lock braking from 100 to 0 km/h time is about 1.8 - 2.1 seconds on every car and on every surface.

I would say that the current tarmac friction values are only about 20% off from the realistic static friction values on some cars, but when the tires are slipping on tarmac, the friction values should be 40 to 70% less than the current values. I don't know about the gravel friction values, but those should be lower than on tarmac and the tire digging in to the ground effect changing the kinetic friction amount.



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griev0r said:
dgeesi0 said:
SamRWD said:
https://www.youtube.com/watch?v=hCnLeOPSv9c

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
you cant see the difference ? i can go set world records on any track with the cars and you cant see the difference i can within seconds of that video playing.the cars dont react the same.they react yes not the same.
Any of the other clips yes you can instantly see the difference how they can hold a powerslide through the corners, even over deep ruts.  You simply cannot do that in D4 in rally, no matter how crazy the setup or car you choose. 

Then how come there are literally hundreds of videos showing people powersliding through corners in D4?

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hawku0 said:
fab1701 said:
SamRWD said:

We could brainstorm if it is not a matter of lack of engine power, however that wouldn't explain too short braking distances.
That one just got me thinking...

Well let's pretend the grip gets lowered. This would help with the rear and the braking distance on gravel would increase. But then, because of less grip, the forward thrust would decrease even more. Now this seems wrong to me.
But there is a difference between braking and accelerating on gravel: Thrown material. Does anybody know how much thrust is created by simply the dirt that gets thrown away by a spinning tire? I bet this can be calculated to a degree. Also, how easy is it that a dirt-pile simply gets shredded away? Maybe thats something that needs to be considered.
EDIT: well i guess the extra-thrust will be minimal, but the tires digging in the ground should find additional grip somewhere down there ;).
There should be different friction coefficients for static friction and kinetic friction. When the tire isn't slipping, the friction values should be close to static friction values, which can be 30-60% higher than kinetic friction values.

So what are these values in D4?

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dgeesi0 said:
SamRWD said:
https://www.youtube.com/watch?v=hCnLeOPSv9c

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
you cant see the difference ? i can go set world records on any track with the cars and you cant see the difference i can within seconds of that video playing.the cars dont react the same.they react yes not the same.
You realize that I was writing about lateral friction after hitting a bank? How it was the same as in D4 's representation of Wales gravel? You also realize how other parameters seem to be even more off? Because it is exactly what  I just wrote in that post. 

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SamRWD said:
dgeesi0 said:
SamRWD said:
https://www.youtube.com/watch?v=hCnLeOPSv9c

Here we go. Cars self recover after going oversteer. Exactly like in D4. It happens when deep loose gravel has a bank on the outside. Wheels get in contact with them, and car straightens itself and depending on the impact can go oversteer understeer (edited). This is how much tyre parameters are off in D4- tyre bites into the gravel so much laterally, that it gives the same effect as in the video! Also please note there is no problem powersliding despite ruts.
you cant see the difference ? i can go set world records on any track with the cars and you cant see the difference i can within seconds of that video playing.the cars dont react the same.they react yes not the same.
You realize that I was writing about lateral friction after hitting a bank? How it was the same as in D4 's representation of Wales gravel? You also realize how other parameters seem to be even more off? Because it is exactly what  I just wrote in that post. 
What bank? There are no banks in the video you've posted. The tyres are clearly not hitting any banks and yet the cars are still staightening out. Why is that? Think about it. 

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Friends, we will construct a formula that will break this elusive spell of high traction that was casted upon our favored game!

To me, Sam's video was VERY enlightening. You can see the precise behaviour the cars make in DiRT 4 right there.
Look at the clip 00:34 through 00:39.
Turn in, loss of rear traction, front tyres pointed forward after turn in during slide, snap to understeer, engine actually bogs down, and then he has to turn into the corner again on exit.

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chukonu said:
Friends, we will construct a formula that will break this elusive spell of high traction that was casted upon our favored game!

How about you break the elusive spell of the messiah complex that you've casted (sic) upon each other. 

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