Cars Physics reworked for the two Maserati 250F 2019-09-13

[alekabul]

alekabul submitted a new resource:

Physics reworked for the two Maserati 250F - Corrected errors and improved feel

When I saw this
View attachment 324304I thought "Waaait, what?!" Yes, you see it too. The physics on both Kunos cars runs ahead of the visuals. But that isn`t the reason for the horrendous yaw wobble. That is simply the consequence of miscommunication between the two teams - physics and graphics. The later worked with the proper center of gravity (CG) of 0.48 front and the physics is 0.52 front CG.
View attachment 324305

Of course that means all the suspensions are incorrect...

Read more about this resource...

 

[Sascha Guenther]

Maybe a stupid question but is it also possible to use your modification for the original kunos Maseratis? I don´t want to have 2 new cars created so I would prefer to use your mod with the existing ones.

 

[alekabul]

I

Maybe a stupid question but is it also possible to use your modification for the original kunos Maseratis? I don´t want to have 2 new cars created so I would prefer to use your mod with the existing ones.

It`s not as simple as putting the contents in the original folders. That "data.acd" file refers to a specific folder name. Plus it reminds me to put a special line in the description as to avoid confusion - these two modified cars won`t work online.

 

[Rufus Baggsby]

I'm a little confused. The photograph showing the suspension layout shows the front wheel ahead of the graphic front wheel. Surely doesn't this mean that either the wheelbase is incorrectly defined in the physics data, incorrectly drawn in the graphics or (as the rear wheel's wire-mesh isn't showing) the graphics just need bringing inline with the physics? I would very much like to understand how the centre of gravity can be of any relevance to the graphic design. My understanding is that the graphics have no weight and cannot therefore affect the car's handling, but I am always happy to learn something new.

 

[alekabul]

I'm a little confused. The photograph showing the suspension layout shows the front wheel ahead of the graphic front wheel. Surely doesn't this mean that either the wheelbase is incorrectly defined in the physics data, incorrectly drawn in the graphics or (as the rear wheel's wire-mesh isn't showing) the graphics just need bringing inline with the physics? I would very much like to understand how the centre of gravity can be of any relevance to the graphic design. My understanding is that the graphics have no weight and cannot therefore affect the car's handling, but I am always happy to learn something new.

The wheelbase in question is the same for physics and visuals. The wheels on the physics model run ahead of the visuals because the CG of the physics model is wrongly defined as 0.52 - 52 % of the weight at the front. All the graphics is defined in space according CG but here it`s oriented towards 0.48 - 48 % of the weight at the front so it is correct and the physics is incorrect. I adjusted the CG of the physics to match 0.48 as is the specification of 250F. Then all the suspensions had to be corrected too. Of course there is a lazy option to move the graphics to 0.52 CG and call it a day but then all the problems with the handling will stay uncorrected and that hasn`t been my goal.
I`m not an employee at Kunos and can only guess the reason for the error been made and gone uncorrected till the last update of the game.
I hope this clarifies things well enough.

 

[Stereo]

It's not an error, you're reading CG from the wrong place, ingame it has 0.485 front (6cyl) and 0.493 (12cyl). The graphic offset's the only thing wrong. You should use the Telemetry app set to wheel loads to see weight distribution, that does it live from the 4 contact patches, same way people measure it irl. Anywhere else is just an estimate based on the weights, it's not done with the actual physics engine AC runs.

 

[alekabul]

Anywhere else is just an estimate based on the weights, it's not done with the actual physics engine AC runs.

Of course I respect your opinion and expertise but the 0.51 CG is in "suspensions.ini" of V-6 (0.52 CG is in "suspensions.ini" of V-12) and I don`t think that reading loads from "Telemetry" has to do with the problem as it shows loads dynamics primarily. The "Suspensions" app shows it illustrated in the first screen and in this post you can see what same app shows after editing "suspensions.ini". Moving the CG to 0.48 is correct and consistent with the real life data from at least two unrelated sources. I get your point that CG in "suspensions.ini" is the graphics offset unaffecting physics but can`t agree to that. How else to interpret this old argument?

 

[Stereo]

No, the graphics offset in car.ini is the graphics offset unaffecting physics.

CG in suspensions.ini is for sprung dry weight only, and at suspension design height, it's not what you'd get if you measure a car on scales. To match that you'll need the same fuel level as it was measured with and use the Telemetry app.

 

[alekabul]

It's not an error, you're reading CG from the wrong place, ingame it has 0.485 front (6cyl) and 0.493 (12cyl). The graphic offset's the only thing wrong. You should use the Telemetry app set to wheel loads to see weight distribution, that does it live from the 4 contact patches, same way people measure it irl. Anywhere else is just an estimate based on the weights, it's not done with the actual physics engine AC runs.

The CG`s in the two "suspensions.ini" affect the physics in a big way because they are the denominator in
"Actual CG height =(FWR+FBasey)+(RWR+Rbasey))/CG_LOCATION%". That affects not only the car when stationary but primarily in motion. I don`t take into account dry vs. curb weights as only curb is relevant in AC according to CM by x4fab. Curb + driver 75 kg= TOTALMASS

 

[Stereo]

yes, which is why you shouldn't move it 4% rearward when it's in the right spot to start with. And that equation is obviously not mathematically correct, it's just telling you what to do with the basey numbers.

You need to take dry and curb weight into account because the "48% in real life" number does

 

[alekabul]

yes, which is why you shouldn't move it 4% rearward when it's in the right spot to start with. And that equation is obviously not mathematically correct, it's just telling you what to do with the basey numbers.

So you insist that moving the visuals only is the correct way to fix the car and then yaw wobble and understeer are going to dissapear? If not, how would you proceed?

 

[mclarenf1papa]

@Stereo’s correct, for the record.

 

[alekabul]

@Stereo’s correct, for the record.

I want to learn more. So you insist that moving the visuals only is the correct way to fix the car and then yaw wobble and understeer are going to dissapear? If not, how would you proceed?

 

[Stereo]

Changing it farther from how the real car is is not a "fix" for perceived problems, you're just making it easier to drive by making it less like the real one

 

[mclarenf1papa]

Your entire justification for making the change was that “the CoG is wrong.” It isn’t, so now I’m not sure what your angle is. Unless you just don’t like how the car drives.

 

[alekabul]

You need to take dry and curb weight into account because the "48% in real life" number does

Does the book on the second screen that states the weight 752.38 kg and CG 0.48 take into account dry and curb and how are you sure that it does when it says only curb?

 

[alekabul]

Your entire justification for making the change was that “the CoG is wrong.” It isn’t, so now I’m not sure what your angle is. Unless you just don’t like how the car drives.

I always start from that "angle" - if I like something why bother changing it? Along the way I try to make meaningful changes. This edited car is more like what`s described in the sources.

 

[mclarenf1papa]

I always start from that "angle" - if I like something why bother changing it? Along the way I try to make meaningful changes. This edited car is more like what`s described in the sources.

Okay, but you made it objectively less physically accurate than it was...I don’t see the benefit.

 

[alekabul]

Okay, but you made it objectively less physically accurate than it was...I don’t see the benefit.

Why so sure? Got the full data?
After seeing that on the first screen I wouldn`t trust Kunos too much for it. And in fact the edit started because of important inconsistency with the real life data - steering turns.

 

[alekabul]

Changing it farther from how the real car is is not a "fix" for perceived problems, you're just making it easier to drive by making it less like the real one

The real one I believe was not constantly trying to dump it`s driver in the ditch. What engineer would put his name next to it if it would not track straight on an ideal flat road like the very yours Test pad?