[ODE] Density units

[Michal Bacik]

Hi,
possibly a stupid question, but what units is the density in ODE in? Maybe,
as with scene metric units, there's no specification of density units, but
I'd like to understand the relationship between density and metric units
used in ODE.

I treat scene units as meters for better imagination, and would like treat
density in kg/m3, but ODE examples define density as constant 20. When I set
mass to density of e.g. wood (which is approx. 500kg/m3), my objects are
really heavy, and do stuck into floor.

Any explanation of why density is set to 20, and not some more reasonable
number, would really help.

Thanks,
Michal