It is exactly because that Ferrari was neither mass produced, nor designed with expense as a priority, that economies of scale were more or less ignored in its creation. It is an exceptionally labor intensive and extravagantly appointed rolling work of art.

And regarding those curves and consistency in their reproduction, the geometry was for the most part well understood long before the technology available to incorporate them in practical designs. It is in classical architecture where we can see mathematical concepts clearly ahead of the engineering and mechanical technology available for their application. And a great many of the constructions and engineering marvels of the age were in fact attempts at the physical manifestation of the proofs from solid geometry. For example, the 2 men responsible for the design and erection of the great church in Constantinople, the Hagia Sophia, were not architetcts at the time. They were in fact academics—teachers in Antioch and the preeminent mathematicians of their age. They specialized in the geometry of the conic sections, and the building they erected remained unsurpassed as a physical expression of that knowledge until the arrival of calculus.

Slide rules, engineers with paper and pencil, draftsmen, precise measurement tools, highly skilled machinists, various jigs and such. Most of us wood workers are still familiar.

Oooo!!! Ooooo!!! I know this!!! Ask me!!!
In engineering school we studied the mathematics of 4 bar mechanisms. We were able to make any shape we wanted by making a fixture that moved our cutting tools.
There are many examples of 4 bar mechanisms in action on youtube. Here is one:
Infinity symbol drawing mechanism

@LuckyGuy Those were very cool. How would they do this in 3d though? did they make cross-sectional 2d slices and stack them together? or are there mechanisms similar to 4-bar mechanisms that allow reliably/repeatably constraining motion in more dimensions?

@Blackwater_Park When drafting something like the panels on that Ferrari, were they simply drawing the orthogonal x/y/z views? or were there techniques for creating other views/slices/cross sections of the geometry at oblique angles?

How did we do it in 3d? Easy! We either used Quaternion mathematics to design the spacial mechanism or we moved the machining pallet at a fixed rate in one dimension.

We were smart boys who listened in class and did all our homework.

In case you are not familiar with Quaterions they were also called Hamiltonions by some users. Here is a description. Quaternion

@gorillapaws I’m not sure if there was anything more sophisticated than X,Y, Z views. I would assume if that detail was needed to machine or fabricate there would have been additional drawings. I’m just old enough to remember using French curve stencils and templates but not quite old enough for slide rules. My dad was a draftsman before he was an engineer and I remember some fancy stuff he did with those. I don’t know what that Ferrari is made out of but if fiberglass there was probably a fitted mold, if metal there possibly were presses and go/no go jigs and such. I think modern cars are still brought to concept using clay. I look at things designed 80 or a 100 years ago and I’m often blown away by the ingenuity.

@Blackwater_park I have a long deceased relative’s Elgin pocket watch purchased in 1919. It still works great. The back unscrews so you can clean and fine tune it. The precision machining is incredible! A work of art.

Or an old miller carburetor from a model T.