[vtkusers] suggest to vtkUnstructuredGridWriter

[Florian]

Hello,

I use the vtkUnstructuredGridWriter to write  *.vtk files. I deleted by
mistake all points from my polydata which is input for my unstructured
grid with the vtkCleanPolyData. My program exited with the warning
floating point exception. I would suggest to add a warning instead that
there are no points. The warning should look like the warning if there
is no input given to the writer. I think for small programs with no
signal handling and other data checks it's not bad.

And I have a question is there an easy way to find all subclasses of an
abstract class? I think in the doxygen data base I could find it, but I
don't know where. Has anybody a hint for my?

regards 
flo