# The units of measurement

Well Hello there!

I am developing a game (like most people here) and I have a class named `Mob`.
This `Mob` is supposed to act like an enemy/monster. It has the function `walk(Dir dir)` where dir stands for direction (`Dir` is a sub-enum). The mob has a `RigidBodyControl` called physical. I want to apply a force or linear velocity to the physical, but I don’t know what the units of measurements are.
I know the units are relative, but can someone atleast explain to me in what way the vector given for `applyCentralForce(Vector3f)` is relative to the movement of the object.

I wanted to solve this myself, but `RigidBody` is full of compiled code.

~MisterCavespider

If your mob is tall 1m in real life and 10 units in your game, 1 unit of movement means 0.10 meters.
Keep in mind that the default gravity in bullet is 9.81 so 1m=1unit, if you want to use a different scale you need to change the gravity accordingly.

Shorter answer: Use 1m = 1 unit and you will be fine.

Sorry if I didn’t explain it well enough.

That is only distance.
I want to know the unit for force for the following reason:
The game mechanics I want include formulas for accelerations, to carefully control scripting (in cutscenes and things like that). For this, I need to calculate the needed force to get the wanted velocity and distance travelled.

My question is mainly: Does jME3 use (Kilo)Newton? If not, what is the formula it does use?

~MisterCavespider

Yes, 1unit = 1newton if you use 1unit=1m scale and 1 unit = 1kg.

@RiccardoBlb Thanks!