...
Since MultiBodies can consist of a lager number of objects, it would be a major limitation to use the same mass value for all items. With a density-based approach it is possible to overcome this restriction, because now small parts will also have low mass. Density is defined as mass per volume [kg/m3].
@ air Friction
In real life, the movement of an object is always decelerated because of various friction effects – a vehicle on a street, for example, does not roll forever. Even a thin medium like air produces a certain amount of friction. Normally you do not observe this force, but with higher velocity, you will start to experience a growing resistance – air friction. So, if your simulation happens on Earth or a planet with an atmosphere, it is always recommended to add a certain amount of air friction. Very high values can even stop an object completely.
...
Sometimes you do not want a simulation to start from zero, but the objects do need an initial velocity. This parameter assigns , measured in metres per second [m/s], assigns such a behaviour by simply entering positive or negative values. Keep in mind that “@ Velocity” directly determines the body’s trajectory and a value of [ 2,0,0 ], for example, creates a linear motion along the positive X axis.
...
This parameter actually works the same way as “@ Velocity”. Instead of an initial velocity, you can add an initial rotation mostly to avoid a uniform look. You also have three values and each one is measured in degrees per second [deg/s]. Negative angles settings are, of course, accepted.
...