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Differential Configuration link please

Forum Overview >> Farming Simulator 19

CategoryFarming Simulator 19
Created11.01.2021 03:28

Fuman 11.01.2021 03:28
I have the spent today wrapping my mind around the motor configuration and coming to terms with the different fields and how they affect a vehicle. For a newbie, I can make a fairly reasonable torque curve across an rpm range that somewhat behaves as I expect. The video and article by Jens Ejvinsson was very useful in coming to a basic understanding of the topic.

However, I am now wrestling a new beast... the differential configurations.
Could someone please share a link to any relevant articles or videos please?
The results of my searches have lead to dead ends.

Thank you

Fuman 11.01.2021 03:48
According to the documentation provided here by giants, if I use their formula, then my vehicle should have a top speed of seven thousand sixty eight miles per hour (7,068mph).
But in game, it only goes 37mph....

<differential torqueRatio="0.5" maxSpeedRatio="1.5" wheelIndex1="1" wheelIndex2="2"/>
<differential torqueRatio="0.5" maxSpeedRatio="1.5" wheelIndex1="3" wheelIndex2="4"/>
<differential torqueRatio="0.5" maxSpeedRatio="1.5" wheelIndex1="5" wheelIndex2="6"/>
<differential torqueRatio="0.5" maxSpeedRatio="1.5" differentialIndex1="1" differentialIndex2="2"/>
<differential torqueRatio="0.5" maxSpeedRatio="1.5" differentialIndex1="3" differentialIndex2="4"/>

<motorConfiguration name="Fu-360" hp="360" price="0">
<motor torqueScale="2.756" minRpm="850" maxRpm="3600" maxForwardSpeed="60" maxBackwardSpeed="20" brakeForce="5" lowBrakeForceScale="0.09" rotInertia="0.00443">
<torque normRpm="0.331" torque="0.2"/>
<torque normRpm="0.425" torque="0.25"/>
<torque normRpm="0.519" torque="0.3"/>
<torque normRpm="0.614" torque="0.35"/>
<torque normRpm="0.708" torque="0.36"/>
<torque normRpm="0.803" torque="0.3"/>
<torque normRpm="0.897" torque="0.25"/>
<torque normRpm="0.992" torque="0.2"/>
<transmission minForwardGearRatio="18.75" maxForwardGearRatio="200" minBackwardGearRatio="40" maxBackwardGearRatio="200"/>

Try it out for yourself.....

function VehicleMotor.calculatePhysicalMaximumSpeed(minGearRatio, gearRatios, maxRpm)
local minRatio
if minGearRatio ~= nil then
minRatio = minGearRatio
minRatio = math.huge
for _, ratio in pairs(gearRatios) do
minRatio = math.min(minRatio, ratio)
return maxRpm * math.pi / (30 * minRatio)

Yes, I'm not using it correctly, of that I'm certain... but again, I think the issue resides in the differential configurations.

Thanks again, and in advance for any mentoring that can be provided...

Bilbo Beutlin (BBeutlin) 11.01.2021 12:32
I don't know how you have calculated your torque curve, but there should be at least one point on rpm range where the torque is 1.0.
There's a good guide with calculator in general forum:

For differentials look into default vehicle xml's for examples.
By searching with Google you'll find further infos, also posted here on GDN.

Fuman 11.01.2021 16:17
It was the article by Jens Ejvinsson that lead me down this rabbit hole in the first place.....
And looking at the ingame xml may give some idea as to structure, but it does nothing to explain purpose or function.

Look at this snippet from the ingame Lizard Warrior:

<differential wheelIndex2="4" wheelIndex1="3" maxSpeedRatio="1.3" torqueRatio="0.5"/>
<!-- middle -->
<differential wheelIndex2="6" wheelIndex1="5" maxSpeedRatio="1.3" torqueRatio="0.5"/>
<!-- back -->
<differential maxSpeedRatio="1.2" torqueRatio="0.5" differentialIndex2="2" differentialIndex1="1"/>
<!-- middle-back -->
<differential wheelIndex2="2" wheelIndex1="1" maxSpeedRatio="1.3" torqueRatio="0.5"/>
<!-- front -->
<differential maxSpeedRatio="1.3" torqueRatio="0.5" differentialIndex2="4" differentialIndex1="3"/>
<!-- middle-front -->

ONLY because the comments were added was I able to indentify which wheel or wheel group was being referred to.
But, how do we ascertain the relationship between the placeholder variables and the actual ingame truck and what effect to the numbers have?
It's one thing to simply copy this verbatim, and then have the audacity to call it a mod, and another thing entirely to use different values that have a predicted result based on an understanding of what each constituent part is and does.

So, if anyone has a link that explains the voodoo, please share!

Fuman 11.01.2021 16:17
[edit] double post... sorry

But since we're here, let me say to Bilbo directly: I mean no offense, and am very grateful for the mentoring you provide in your responses. I am, I believe, stating a truth that Giants Software makes this process more difficult than it has to be.
I for one, would gladly pay for documentation that would alleviate the mystery and allow me to move forward to create and enjoy the fruits of my labor.
But without some form of documentation explaining the labor already done by the developers at Giants, then the difficulty has far outpaced the pleasure.

Maybe, modding isn't for me ? At least not in this fashion.

P.s, my torque curve was a 16 point curve that did in fact contain a point for max rpm (1.0) at point 10 in the curve,,, I copy pasted only the first eight points in the original post.

for what's it's worth, I now have a truck, "Fumans Grunt Truck", HP_360, MaxRpm_2200, topSpeed_51mph, maxHP @ 1863_rpm.
but in truth, it' just the Lizard Warrior wearing a Grunts clothing...despite having a unique torque curve....

Bilbo Beutlin (BBeutlin) 11.01.2021 17:24
Sorry, but there is no complete documentation from first steps to detailed description of methods on high level. And there will never be such kind.
So 90% of a modder's work is individual research. If you can't live with that, better forget modding.
You can be happy that FS19 is out for over 2 years. Apart from tiny official documentation people have found out a huge amount of undocumented stuff and published it in web. Use Google and you will find mostly what you need.

Eg. by searching for "fs19 differentials" you will find in the very first hits explanations from myself.

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