Leonardo Da Vinci saved 13,000+ pages of notes and drawings on anatomy, physiology, engineering, mechanics, geometry, mathematics, bird flight, flying machines, botany, proportions, topology, weaponry, musical instruments, art, and more, all in mirrored shorthand written from right to left.
the terminator did the same but not for painting...
That's not 100% accurate. He, and many before him dating back to Polykleitos of Classical Greece, studied the the aspects of proportion in nature (and the human body) to find the most perfect balance for art, architecture, and engineering.
The Vitruvian Man was an attempt to correct the inaccuracies of the calculations of the ancient Roman architect Vitruvius.
The calculations were used to create paintings and sculptures of the "perfect" human form, but not solely for that purpose.
I think you split the hair too fine. "Only" was an indirect reference to enhance the skill, not an imperative sigular aspect.
This is correct. Opinionated, but correct.