I am learning about vtkAlgorithm via this article.
I see a mention of this call self.Modified()
I am unable to find any documentation of this method nor is there any similar counterpart on the C++ side of vtkAlgorithm.
What does it do within the context of Python that requires this call that we do not need to do in the context of C++ using vtkAlgorithm ?
Modified() is a C++ method of vtkObject, and it applies to the C++ vtkAlgorithm in the same way as it does to vtkPythonAlgorithm. The only difference is that most of the C++ Set methods are implemented with vtkSetMacro, and this macro automatically calls Modified() when it sets the parameter.
As for the purpose of Modified(), it’s fundamental to the operation of the VTK pipeline. Modified() sets the algorithm’s timestamp, so that the pipeline knows that the algorithm has to be re-executed the next time the pipeline is updated.