SetRepresentationToWireframe problem....

I use SetRepresentationToWireframe as follow:
The frame looks like corrode as shown.How to deal with it?

            self.original_mapper.SetInputConnection(self.original_model.GetOutputPort())

            self.original_mapper.ScalarVisibilityOff()
            self.original_actor = vtk.vtkActor()
            self.original_actor.SetMapper(self.original_mapper)
            # self.original_actor.GetProperty().SetColor(0.5, 0.8, 0.5)
            # self.original_actor.GetProperty().EdgeVisibilityOn()
            # self.original_actor.GetProperty().SetRepresentationToSurface()
            self.original_actor.GetProperty().SetColor(1, 1, 1)
            self.original_actor.GetProperty().EdgeVisibilityOff()
            self.original_actor.GetProperty().SetRepresentationToWireframe()
            # self.myTrans = vtk.vtkTransform()
            # self.myTrans.Translate(1500, 2000, 20)
            # self.original_actor.SetUserTransform(self.myTrans)
            self.renderer.AddActor(self.original_actor)
            self.renderer.ResetCamera()

Maybe try setting diffuse to 0 and ambient to 1 and see if that fixes the issue

Do you have antialiasing enabled? If so, try disabling it and see what happens. FXAA was observed producing artifacts like that before.