Origin story

The center of your game world is called the origin. The origin is the magical place in 3D space where everything begins. 3D space is divided into three axes: X, Y, and Z. If you remember your Cartesian grid from grade school, or if you've ever seen a bar or line graph, the X-axis runs one way (usually horizontally), and the Y-axis runs perpendicular to it (usually vertically). 3D is like taking a second piece of paper and sticking it at a right angle to your graph so that this axis is perpendicular to both X and Y-axis and you have a third axis firing straight up at your face from your desk, and down into the floor in the opposite direction.

The orientation (the way the X, Y, and Z axes are positioned) varies from program to program. Unity has a Y-up orientation. The X and Z axes run perpendicular to each other on the "floor". If you hold your arms out like a scarecrow, your arms are the X axis, and the Z axis runs through your belly button. The Y axis runs straight up into the...