Hi,

I am using NGBem to solve a boundary integral problem on a 3D mesh. This then returns a function `g`

in `SurfaceL2`

. Since I want to solve a problem like the tutorial problem, I now need to extend `g`

to a `H1`

function, defined as zero in the interior, and equal to `g`

on the full surface `outer`

. The `order`

of all spaces is 1. An interpolant is fine, or some projection method is fine. I am not sure how to implement this. Imagine it is structured like the following:

```
def interpolate_surface(g: GridFunction, mesh: Mesh) -> GridFunction:
#some interpolation method, relating
#the `SurfaceL2` GridFunction `g`
#to a `H1` GridFunction `g_h`
return g_h
```