How can I modify this surface from green line to cyan line?

Hi!!! I need help to modify this surface… I try with the FLow along curve command, but the result is bad… Anybody help me???Surface.3dm (162.9 KB)

I do not see a good way to do this cleanly- is the goal to make a 2d pattern? The ‘material’ will need to deform a good deal - it may be that Squish can help, but I doubt it can do this heavily curved a surface in one shot, it may need to be split into strips.

-Pascal

Ok Pascal… but split into strips the result is bad…

Thanks one more time!

Pascal was right! This isn’t really clean, but it’s a stab and it’s within .3-.4 sq. mm of the original object’s surface area. Not sure if the flat surface would be able to actually “deform” to match the surface you presented, but the underlying structure gives hope.
Looks like you measured the length of the green line and drew a cyan line of that length. Reasonable guess/start, so I followed by trying similar logic. I had to move the object to the center of the construction plane so some of the modeling choices I made would work.
First, DupEdge on both surface edges, the shorter, flatter one at the bottom and the longer one with the more bell-shaped curve.
Rotated the object in a couple of viewports to square it up on the construction plane, as much as possible.
Measured the length of the duped edges for reference
Bottom duped edge, Project to C plane, measured, 1D scaled up & down a couple of times to get close to the original curve’s length, Because the curve isn’t a straight line (ends curve up a bit), I got to within less than 1 mm of the original curve’s length. Subtracted my shorter curve from the original length, and drew a straight line, both sides, from the origin, split the curve I’d been messing with at the center, moved each curve half to its respective end on the short line from both sides, joined and now the flat curve was the same length as the original on the curved surface.
Switch to Front View, took the longer bell-shaped duped edge curve from the upper portion of the curved surface and used Project to C Plane, Then, ReMap to C Plane to put the flattened curve roughly in position in the Top Viewport.
Orient 2 Points w/3D scale to snap to the ends of the bottom curve.
!D scale to raise the top of the bell-shaped curve to the top end of the cyan line.
Turned on Control Points and snapped end points so both curves would Join.
Checked area and was under-sized by +/- 500 sq. mm
Turned on Control Points and Nudged/Scaled points on sides wider until within above-listed tolerance.

So, it starts with measurements based on original surface’s outer dimensions, flattened, and original surface’s outer profile shapes, roughly. Then curves were pushed around to get area measurements that are reasonably close. Original surface was just under 2800 sq. mm. and the flattened version is within about .3 sq. mm.

Not sure what you plan on doing with the flat version, but it could plausibly be formed in to the original surface.

Divide original green curve in to X-number of segments
Extract Isocurves, snapped to each segment point
Measure length of each isocurve
Reconstruct segmentation on cyan curve
Draw corresponding length curves at right angles to the cyan line, centered on the segment points
Loft the horizontal curves and you should be pretty darn close, probably better than my first attempt.

Best regards,
Doug

PS, I’ll still attach my results for the first method, but I like the second one better; it sounds like it would be a better match, with better fidelity to the original surface’s dimensions. Give it a shot and let us know.
Surface.3dm (157.9 KB)

Squish the surface and the green curve.
Scale the squished surface and green curve so that the length of the squished green curve matches the length of the cyan curve.
Move/Rotate/Orient the squished surface and curve as desired.

I understood the explanations , the result was great and gave me other ideas to other projects, but I do not need to plan this surface , I need only to change the profile, leaving the green profile and go to the cyan profile. Volumes may vary slightly , will have no problem, the only problem is leaving a profile and go to the other . I tried with FlowalongCurve and could not , FLowalongsurface did not work … Thanks for returns !!!