Finally

I've got a solution.

Ta da

After, I don't know 1.5-2 years of messing around with this, I've finally got a working method for creating these surfaces I need to the quality I desire.

It's G3. It's beautiful.

The scene:

Next, I'll make an infinite line that captures the side profile of the front of the nose

I want 16 evenly spaced points from 350 to 2200

I only need the first and last 4

Make a series of lines from the first four points up to the infinite line in the zx direction

Hide infinite line, put a point at then end of each of these lines

Hide the support lines. Draw one line from the first control point to the last one

Hit control points, this will create a new line. Right click on the number of control points, change this to 16. There are now 16 evenly spaced control points.

Hide the old line and control points. We'll use the Manipulators snap to constrain this control point to the point earlier created

Select the first point

Snap to this point

Should look like this:

Repeat

For the points at the top - right click on the control point and select Edit position

Change the y position

Repeat for the top 4 control points

1) Select Grid mode
2) Set translation to something reasonably large
3) Use the handle to move the points only in the y direction

Start moving the control points to approximately the line we intend

Curve is getting there. Now change the translation distance to something finer to start fine tuning the curve control point by control point

Here is my result. Some of the control points have to be pulled way out to get the desired spline shape.

Select all points

Right click on any of the points and select Keep all points

Hide everything but these points. We've now got all the control points necessary to replicate this spline

Lets do it all again from a side view

Infinite line

Points on lines

Line with 16 control points

Snap manipulators, edit points

Adjust curve using control points, keep all points

Hide all this for now. We're going to make a support surface

Make a point using the first control point as a reference at y=200. Do the same for the last control point

Then make two more points using these points as a reference at z=200.

Make a 4-point patch using these points

Make this surface symmetrical across the zx plane

Blend. G3

Hit control points, make this blend have 16 control points in the v direction. This is our magic surface.

Hide the support surfaces, unhide the side view points we're going to snap to

I'll apply a material and paint it blue as well, so it's easier to see the support we're working with

Working with control points, make symmetry across the zx plane and highlight the first set of control points as shown in the box

Select this control point

Snap to this point we created

Snap the rest of them

Want a surprise? Check it out from the top

Unhide the top view points and snap the control points again

So far so good

So lets say we've got one dimension completed. The y direction

Let's work on the next dimension. Z

I'll make a 3d curve representing approximately what I want to accomplish in the z direction

Select the 3d curve and click on Distance Analysis

Select our surface, change the Measurement Direction to z, and change Display Options to Full Range of Colors

Now I can see how far off I am.

Before I start going crazy adding control points u direction, I think it's worth understanding how the distribution of control points effects the shape of a curve.

Here is a G3 curve created by blending two straight lines using a tension of 1.

I'll set a target of how high I want it to look in the center

Here is what it looks like with a "Linear Law" adjustment

Concave Law, notice the effect of not evening spacing the control points

Convex Law

Bell Law

Comparison of all four

So before I start adding control points in the U direction on this surface, I'll try to get as close as possible to the shape that I want by using the appropriate spacing of the existing control points.

So maybe first things first. Use linear law adjustments to get the surface as close as possible in my distance analysis, remembering to maintain G3 continuity at the start and the end.

Alright, that looks pretty nice. I know that the there is a lot of red, but that is simply the "min/max" showing me the points where things are out the most. We can see that it's all within 1mm tolerance. Good enough.

So lets say for a moment that 2 dimensions are now done. Y and Z

So what's left is the shape of this surface. Here: (all the way through the model)

This is going to be pretty subjective.

I know about these lines in 2 dimensions

So I'll project them onto my surface to help as guides

Another trick here; create an offset plane

And calculate the intersection of the surface and the plane

I've got this set at the mating point between the nose and the monocoque

But I think this should be much more "convex" than it is now

So I no longer want these CV evenly spaced in the z direction

Something more like that

Makes a "rounder" curve here

Which makes more of my projections fit

Biggest issue is going to be here

At this point I'm going to introduce two more control points in the u direction

And really go extreme messing with the control points

I think that's pretty much going to do it.

All my guide lines fit up pretty much perfectly

So why go through all this work?

Extrapolate the side

Go through and edit all the bottom points to be z=0

Something like that

Extrapolate the top of the nose

Then the side of the nose

Around the cockpit

Run a connection checker analysis

It's all perfectly G3. Meaning I have all these great surfaces I can use to build the next features