Flattening 3D panel with complex curve

Does anyone know how to flatten a curved panel in Rhino 8 without the tessellation and “squish” process, so that it can be rendered flat as a complete unit with all original dimensions intact?

The attached photo is the curved panel of a boat hull that I am trying to flatten. It is to be made from 3/8” thick material, and needs to be accurately flattened for CNC cutting from flat stock material.

I’m stuck and would appreciate any help…

is that a developable surface? if so unroll should do but you might need a single surface then for a better unroll. since the centre of the sheet metal at least should stay within the dimensions

if its doubly curved it will get more complex. Rhino 9 has some new stuff for squshing that might help here.

if you want more help posting some of your geometry might help. a screen shot causes a lot of guessings and lost time.