What is SetSampleDimensions in vtkSampleFunction?

Referring to the example found here:


I know that increasing the arguments SetSampleDimensions seems to increase the mesh density (I think), and generally makes it slower, but beyond that I am not sure what exactly this is doing. The doc string says: Specify the dimensions of the data on which to sample, but I am not sure what this means exactly. Can anyone shed some light on this for me please? Thank you.