Actually, a unit doesn't have any defined real world length, you just define a unit to be a good size that suits you game.
For example:
I'm 180 cm tall.
If I decided that in my game, one unit is equal to 1 cm, then I would make my model 180 units tall. If I decided that one unit would be equal to 1 meter, then I would make my model 1.8 units tall.
What size you give your units really depends on the game you are making. Just remember to be consistent
- If nothing sticks to teflon, then how do they make teflon stick to the pan???