[Paraview] smoothing isosurfaces on unstructured grids

[Stefan Ringe]

Hi!

I am using unstructured grid files of format x y z f(x,y,z) (so 4 
columns of data points) which I import as VTK particle data. I want to 
plot a smooth isosurface. I already tried the Delaunay3d, but there are 
2 main problems with it. 1. it seems to cut off hills of my surface and 
create straigt lines to combine the top of the hills, so that in the end 
it looks like there are really large areas on the surface spanning from 
one hill to the other. 2. my function is also not that smooth so I would 
like to smooth the result in the end. However the smooth filter is 
greyed out, if I select my data file or the Delaunay3d input,

Stefan