Function build_pcurve_on_surface_stations 

pub fn build_pcurve_on_surface_stations(
    surface: &NurbsSurface,
    stations: &dyn Fn(f64) -> Result<Vec3, String>,
    breaks: &[f64],
    tolerance: f64,
    base_samples: usize,
    refinement_rounds: usize,
    parameter_cap: usize,
) -> Result<NurbsCurve, String>

fit_pcurve_on_surface_stations for the callers that only need the curve, accepted or refused on its bar (accept_fit).