How to prevent points from disappearing when zooming in?

Hi all
I am a beginner with VTK, it’s interesting and I’m currently learning through examples.
When I try the example of Delaunay2, I noticed that the points disappear when the camera is zoomed in to a certain extent


It possibly because they are being occluded by the surfaces. When the surface is at an angle, (like this), the points are still partially visible.

Is there any way to avoid the issue of points being covered and thus disappearing? I hope to see the points clearly at zoomed-in distances, just like their original appearance.
Any advice or suggestion would be great.