As of late April, this no longer works due to changes made to the glass material, as stated in this post. This affects both the reflections and the ability for the glass to be fully transparent.
For the invisible glass, a new canvas material will be added to fill its spot. This functionality being achievable with canvas items is an overall plus, as the varying shapes allow for more options and more complex/accurate clipping. Off the top of my head, somewhere this could be used is in the Underwater condo, to prevent use of the transport tubes while not affecting movement around said tubes.
For reflections, using the “Glass Opaque” gives a similar effect. The caveats to this are that you can not change the color of the glass, as well as it will include screen-space reflections short-to-medium distances.
I’ll update this post again once the new material is added, probably with a re-done version of the video.
A video I made explaining glass.
I’m gonna be honest, I think glass walls are one of the most versatile items in the game.