Using Depth Mask Shader to Cut hole though geometry Show Background

[Lichemperor]

I’m Trying to make a masking shader to cut-out shapes in my geometry, and display the skybox behind them.

Here is an example of precisely what I want and a brief guide on how to achieve it:

How to cut a hole through geometry to the skybox using just one camera

Unfortunately, instead of the Skybox, it renders those pixels in black.

What could I be missing?

[MaximBesters]

You probably already fixed it, but is the clearflags of your camera set to skybox?