Hello Ian and realthunder,
I just accidentally closed the wrong window with my lengthy explanation version; so, here are the highlights
I see your points and agree with them 99-percent Ian.
These are "magic numbers"! They are not necessarily vectors. You could use vectors for simple 3-ax machine running linear.
These magic numbers are defining a state; or more accurately a DIRECTIVE of how to generate path vectors (is this the intent/correct realthunder); i.e. METADATA for lack of a better word.
Here is the missing 1-percent.
- cncaxis.png (6.35 KiB) Viewed 2338 times
If a machine has a fourth axis; in this case A-axis, you will be looking for that magic number (list/enumeration or whatever you want to call it).
I think, to define a motion/movement on the A-axis using vectors, would now require minimum two (2)vectors and maybe minor kinematic calcs.
From what I know, (I dont have an A-axis yet) typically, movement of A-axis is defined by rotation: degrees, radian, etc.; at least in one case I am sure.
Thats where realthunder's extensible list could simply include rotary action/definition; thats why I have to agree with 99-percent of what he is saying!
Hope this can be of some value!