Get single contour from vtkPolyData

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4

Thank you for your ongoing help! I understood and followed your suggestion.

I subclassed vtkCallbackCommand. Inside its overridden Execute()-function I got this far:

void HPvtkRenderCallback::Execute(
    vtkObject* caller, unsigned long eventId, void* callData
)
{
	std::cout << "Render callback" << std::endl;
	std::cout << "Event: " << vtkCommand::GetStringFromEventId(eventId) << '\n';
	auto* renderer = static_cast<vtkRenderer*>(caller);
	double d1 = renderer->GetClippingRangeExpansion();
	double d2 = renderer->GetClippingRangeExpansionMinValue();
	double d3 = renderer->GetClippingRangeExpansionMaxValue();
	vtkActorCollection* propCollection = renderer->GetActors();
	propCollection->InitTraversal();
	for (vtkIdType i = 0; i < propCollection->GetNumberOfItems(); ++i)
	{
		vtkActor* actor = propCollection->GetNextActor();
	}
}

The calIback generally works. However, now I’m having problems getting the correct actor.
With this actor, I planned on:

  1. getting the actors mapper
  2. getting both mappers clipping planes (front and back as you said)
  3. calling vtkPlane::Push(double distance) with either d1, d2 or d3 (not figured out yet)

I am using VTK-9.0, so SetObjectName()/GetObjectName() is not an option.

How do I distinguish the correct actor from others?