I have the following function:

```
def interpolateToGrid( mesh: vtkPolyData, grid: vtkStructuredGrid, gridSize ):
# Perform the interpolation
interpolator = vtkPointInterpolator()
gaussianKernel = vtkGaussianKernel()
gaussianKernel.SetRadius( gridSize*15)
gaussianKernel.SetSharpness(10)
interpolator.SetSourceData( mesh )
interpolator.SetInputData( grid )
interpolator.SetKernel( gaussianKernel )
interpolator.SetNullPointsStrategy(vtkPointInterpolator.CLOSEST_POINT)
interpolator.Update()
#output = interpolator.GetOutput()
output = vtkStructuredGrid()
output.DeepCopy(interpolator.GetOutput())
return output
```

grid initially had 2 scalar arrays

The returned vtkStructuredGrid object I get from `interpolator.GetOutput()`

has 14 more arrays

The new arrays - `[stress_xx, stress_yy, stress_zz, stress_xy, stress_yz, stress_xz, vonmises, strain_xx, strain_yy, strain_zz, strain_xy, strain_yz, strain_xz, displacement]`

I understand these values are related to FEA

but I am not able to find the origin of these new arrays

neither in the documentation nor in the source code

Kindly help