Appending Delaunay output

Hi all,

I am creating a curved surface and to tightly control the triangulation I apply the vtk Delaunay stepwise. I would then like to connect everything as one to later export it as an STL or vtk file. I have tried using the vtkAppend filter but I get the error message that vtkDataObject is required instead of a vtkAlgorithmOutput. Does anyone have any suggestions how i can triangulate stepwise but only get one result output?
Thanks in advance.