Mass units?

[Leadwerks]

Is there a standard unit that is defined as one unit mass in Newton, or is it all just relative? If you wanted to realistically define units, what would you set one unit mass in Newton to? Grams, kilograms, something else?

[JoeJ]

No, there is nothing like this.
For size you choose a value so that floating point precission covers your world well, e.g. 1 unit = 1 meter.

For mass you should do the same by choosing units that fit resulting force magnitudes well.
To find that, you could observe the contact forces of your typical game objects and scale masses until they have an average length close to 1.

Personally i use kg for the unit, but i did that just randomly and my force magnitudes seem pretty large.
Now it's some work to change all force related things afterwards but maybe 1 unit = 1/10 kg would do better.