Y is Y up?

Rising World uses the JMonkeyEngine, and there is, like in many game engines, the y-axis for up and down.

X Y and Z are just variables not directions. the same can be said about up down left and right, those are just words. They can be labeled anything. It doesn't really matter what x, y up or down is, they are just directions. This is more of a philosophical question like why are we here, why is the sky blue or why is up up and not down or left.

so true @sagsave they are just variables.

whether X Y Z is like this:

or like this

the truth behind what they represent in each individual situation is what really matters.