Surface my Torpedo (no trimmed surfaces allowed)

Why is it important to keep the spacing along the length the same?

It depends on what the mesh will be used for.

Well none of these techniques result in a usable surface.
i cant over extend and trim back. No trimming. Using Sweep2 with 3 curves does not work in Grasshopper in the instancesI tried it.
Yesterday I learned the trick odf using RULED SURFACE to cap and loft. I note it produces a singularity with 3 curves.
Trimming out the convergin corner and using a patch, is far from optimal and PATCH is verboten for creating surfaces to import to Maxsurf.
Cutting long sweeping surfaces into parts removes the effect of u lines on the v surface without subsequent extensive surface matching in Rhino, undermining the point of using a parametric solution to effect changes to designs quickly. I also note that there are currently no tools available in Rhino 6 to evaluate surface matches other than a zebra which is sub optimal.

I would love to hear about clever ways to brake up 3 curve surfaces. There must have been a long thread on that in these forums at some point? any links would be most appreciated.

The problems with these singularities are most likely what are preventing my model from being joined into a closed brep.
Some this is probably my modelling, but this an order of magnitude more demanding than it “should be” IMHO

So this proxy problem of MAXSurf is what the goal is now? It is good to know that MAxSurf does not need it to be a solid in Rhino.

Take the surfaces over to MAxSurf and give it a try.

This problem is an order of magnitude more demanding them it needs to be, I completely agree. But, the layers of requirements you put on this are making it so.

This problem still needs to be defined as where is the model going and what do you need it for?

  1. Grasshopper definition? Solved with the first reply. Easy to change and analyze.
  2. Cfd mesh? Quick ways to make a mesh. Depends on which cfd.
  3. Make this surfaces with singularities and transfer it. MAxSurf can handle it.

Ask your customer what product he is using and what he is using the model for?

Or you can continue to struggle to shoehorn a 4-sided NURBS surface into a 3 sided patch.