This webinar takes an introductory look at workflows with Programmable Filter / Source in Paraview. For many years, one of the most underappreciated features in ParaView has been the ability to define custom objects using Programmable Filter or Source. These tools could be useful for defining new spatial discretizations (e.g. grids), for creating custom objects in 3D, or even for reading non-standard data from files. In this webinar, we will show some of these workflows.