I am trying to set up a new pipeline in VTK. Therefore I specified a custom class to represent poly data, named Mesh which inherits from vtkPolyData. Further, I implemented a class MeshAlgorithm which inerhits from vtkAlgorithm. The new algorithm class should only accept Mesh objects as inputs and only produce Mesh objects as outputs. At last a third class MeshReader inherits from MeshAlgorithm. MeshReader takes 0 input arguments and produces 1 output object of type Mesh.