vtkAbstractPicker is an abstract superclass that defines a minimal API for its concrete subclasses. The minimum functionality of a picker is to return the x-y-z global coordinate position of a pick (the pick itself is defined in display coordinates).
The API to this class is to invoke the Pick() method with a selection point (in display coordinates - pixels) and a renderer. Then get the resulting pick position in global coordinates with the GetPickPosition() method.
pickPosition (get Array)
Get the picked position
pickFromList (set/get boolean)
Determine if the picking will be processed on all the actors of the renderer or from a list of actors
pickList (set/get array)
Define the list of actors that will be tested for the picking (if pickFromList === true)