Calculation/method of decreasing diameter?

[piginapoke]

Can someone point me to the calculations or the method that determines the required curve, angle and length of the adjacent part of a aircraft fuselage as it decreeases in diameter towards the nose?
See attached pic to show the changing angle and length.

[henryk]

Sorry, this is descriptive geometry - either programs like Rhino, "grids"(siatki) or a blender. It's not that easy!

[airdave]

I don't think there can be a specific calculation, since:

the number of concentric parts is determined by the designers.

More connections allow for a transition that better matches the original shape,
but less parts allows for easier construction and less seams.
So its a designer's choice.
Only limited by overall scale.

Also, aircraft fuselages are often not circular (tube cross-section).
And the central axis often changes position as it moves down the length of the fuselage 'tube'.

I don't see how there can be a consistent calculation or geometry to designing a fuselage.

Most fuselage designs just mimic the overall shape and dimensions, based on a three-angle process.
Most designers base the 3D design on a three-view set of plans.
Most designers rely on 3D software to do all the calculations
and extrapolate the individual parts based on the designers input (3 view plan) and designer's preferences (scale and number of parts).