You may already be familiar with the X and Y axis from math class. Remember having to graph lines and equations of the form y = mx + b? Well, 3D adds another wrinkle to this: the Z axis! Where X was "left" and "right" on graph paper and Y was "up" and "down", Z adds a third dimension: depth. That's right, the Z-axis pops right off the page! So how does one go about graphing it? Well, on paper, it usually involves drawing a diagonal line, putting tick marks on it and plotting points. This is not without its problems, so the preferred methods are orthographic projections, isometric projections and perspective views, all of which will be elaborated on in the following sections.