Inertia

[justinas91]

Hi

Can someone please explain what each value do the 1650 then the 1750 and the 370 why there are 3 values why not 1 value?

Inertia=(1650.0,1750.0,370.0)

And maybe someone found out the realistic value of inertia to 1 mass unit to make mass and inertia as realistic as possible so the handling would be also realistic?

Thankyou

[Kazumi]

Can't explain.

This will probably help

http://www.nogripracing.com/forum/sh...d.php?t=285142

#7 Niels explains the box inertia. But a car is usually more complex then a box with the same mass density overall. So heavy things on the outside of the car (at least not in the center) like the engine will increase inertia. Hence for example mid engine cars got lower inertia for the same overall mass compared to front engine cars as the engine is closer to the center of mass.

However tools and averages only lead this far... don't take them as absolute

[justinas91]

Thanks

[Homeboy]

Originally Posted by justinas91

Hi

Can someone please explain what each value do the 1650 then the 1750 and the 370 why there are 3 values why not 1 value?

Inertia=(1650.0,1750.0,370.0)

And maybe someone found out the realistic value of inertia to 1 mass unit to make mass and inertia as realistic as possible so the handling would be also realistic?

Thankyou

The 3 values are for 3 axes of rotation. 370.0 is definitely for roll, and the other 2 can be for pitch and yaw, but I don't know which is which. My guess is 1750.0 is for yaw because a car is wider than taller, and width contributes to yaw inertia.

Now if you were to lighten this car by, say 20%, you'd want to multiply all 3 numbers by 0.8. It would be a reasonable estimate.

If you want to shrink this car in all dimensions by, say 20%, then you multiply all 3 numbers by 0.8^2 = 0.64.

[justinas91]

Thanks
Will try this out and see how it will work
Just asked about this because some cars have diferent proportions of mass and inertia especialy the lotus is light but has rather higher inertia to weight compared to other cars

[Roger]

I believe that most games work on x,y,z axis for rotation.

Rotation is rotation around the CofG not the centre of the car body (check this first! I may be wrong for NFS)

x is pitch - 1650 in this case (imagine a stick shoved through the car side to side through the CofG) the car pivots around this when you transfer load forward and backwards (braking & accelerating)

y is yaw - 1750 in this case (the stick is vertical through the car now the car swivels around this point when looking down on it)

z is roll - 370

As Kazumi says the car isn't a box with equal mass distribution.

This link is very old, but probably still holds good it has an interia calculation buried within the weight distribution section, read it carefully and try and understand the calculations and you will understand interia.

http://www.nogripracing.com/details.php?filenr=441

Use the calculator and for example just change the mass of the engine - everything will change - car mass, CofG, and Inertia.

Then change mass of engine again and remove and equal amount of mass from somehwere else (maybe fuel) - different result again. They are all connected, but in complex ways.

[Chronus]

The level of detail and the layout of this tool will help anyone who wants to climb the modding mountain, imo.

Try it, guys. Well worth it.