How do I make a selection like this?

[gilbert.hertog]

I have made a shape of a spaceship cockpit. I want to cut out a selection for the windows. How do I modify my selection so that it is smooth rather than with these blocked edges? See image below:

smooth selction.png (751.09 KiB) Viewed 6982 times

For reference, I want to achieve something like this:

windows-example.jpg (66.37 KiB) Viewed 6982 times

I am a bit of a newbe with C4D. I was hoping to be able to draw a selection along the surface of my shape and then smooth that selection out by creating new polygons in between the jagged edges of my selection....

[masterzone]

Unfortunately you are on a wrong way of how to model with polygons. You must model with low poly techniques and the Subdivision Surfaces object. In this way you can make low poly holes and use the subdivision surfaces for smoothing.
If you delete all selected polygons you will get a destroyed objects
Here some tips from a published tutorial: https://www.c4dzone.com/en/blog/tutoria ... ng-440.htm