# Bert class

Namespace: [Grasshopper2.Geometry.Surface](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.geometry.surface.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
public static class Bert
```

Fits a bicubic NURBS surface to an open mesh with a single boundary loop. The mesh is first flattened onto the unit square with a Tutte or mean value Laplacian, then the surface is found as the Riesz representative of the L2 pairing with the flattened mesh in the tensor-product B-spline basis, with the four corner control points pinned to the snapped corner vertices. Thin wrapper over RhBertFitSurface in cmdMathias.cpp (namespace Bert), reached through rhcommon_c; all linear algebra runs natively.

## Methods

- [FitSurface](https://developer.rhino3d.com/api/gh2/type/grasshopper2.geometry.surface.bert/fitsurface.md): (static) Fit a bicubic NURBS surface to an open mesh with a single boundary loop.