Eugene Cojocar wrote:

I'm a little confused. Would you like to enter your own values of moments of inertia around their axis of rotation?

In other words you have moment of inertia around x, y and z axes and would like to use it? For example you have three numbers for moment of inertia and want to use it, like 152.84 around X axis, 169.09 around Y axis and 24.25 around Z axis.

If yes, what about the mass?

Moment of inertia depends on mass and its distribution.

Yes, that is what I want. Your editor calculates inertias based on the vehicle/wheels/parts dimensions and mass.

When you save the phs file, the MOI stored are those calculated by your editor.

What I am proposing and asking is that you'd allow the MOIs to be calculated elsewhere and then stored in the physics (phs) files, thus bypassing the calculations done by your editor.

Why, you may ask? Because either my tool or CAD provide extremely reliable MOI calculations and allow me to specify a lot of factors (as I stated earlier and hinted at: APUs, engine, gearbox, transmission axle, front and rear axles, seats, rollcage, wheels, suspensions, brake disks, pilot, fuel tank, undertray, etc). The results, comparing to official data, differ by less than 1% or slightly higher than that at most (usually well under 2%), even with my own tool.

I can't understand how its possible to use one mass and another moment of inertia if they are related to each other. Or to be more exact, moment of inertia depends on mass.

There is some confusion indeed, as I never said that I would use "one mass" and "another moment of inertia". MOIs depend on mass and distribution (hence the importance of object dimensions and of knowing the location of the major - and minor - masses in a car). We must calculate each objects MOIs in regards to its own COG, and using the Parallel Axis Theorem, calculate the MOIs of those objects in regards to the COG of the whole vehicle.

As I have been saying for years, MOIs, together with tires and suspension design, the most important aspect of vehicle dynamics, and one often overlooked in regards to overall vehicle behaviour.

I use my own MOI calculations whenever a sim allows me to.