In my job, I work with a ton of unit vectors. While tracking things in three dimensions can be tricky, it helps to start breaking down as many aspects of the dimensions to their base components. I’m sure we’re all familiar with common spatial axis labeling. You get X, Y, and Z. Their application isn’t uniform. Some machine uses X for the vertical axis, some might use Z. What you might not yet be familiar with would be the orientations of objects in space. Yes, you can track the cartesian coordinates rather handily with XYZ, but that will only tell you the position of those objects. It won’t tell you the direction they’re facing, and for that we use unit vectors labeled IJK. They’re typically values between -1 and 1, and they can define rotation completely.