I am using Rhino to generate hull surfaces. (they are actually for wave energy converters, but it is similar to a ship hull). I need to create the entire hull surface (portion above and below the water line, where the waterline can be represented as a plane), then I need to delete the portion above the waterline, and just export the portion below the waterline.
It is the same conceptually as what this person was doing: Splitting a surface using rhinoscript and deleting upper surface
EXCEPT, I want to export Nurbs surfaces not a Mesh (the poster above was exporting a mesh). (_SaveAs name.gdf)
The program that I (and the poster mentioned above) are using is called WAMIT and it solves the hydrodynamics of a submerged hull. It can take a mesh, or a Nurbs surface as a series of Nurbs panels. The solution with a Nurbs is much faster and more accurate.
However, WAMIT can’t handle Rhino trimmed surfaces. If a surface is trimmed (as with the Split or Trim commands), the _SaveAs name.gdf command exports the underlying surface, not just the trimmed surface.
Is there a way, or a plug-in, or a recommended way to write a plug-in (I’m already writing a plug-in) to make a “true” split of a Nurbs surface and create two new Nurbs surfaces (Brep.IsSurface = true)?