I set my code to track 1000 random points, and after 2006 seconds (unattended, of course, and only at the 7th point attempted), it errored out complaining about not able to find the point it was looking for: The best point was over 2.0 pixels away. Let me try to relax the constraints a bit and see how it will do. But the question now is: How does Paraview do it?