How does 3D glass etching work? Where it looks genuinely 3D inside the glass?


Examples [here](, [and here](, or even [here]( Sorry I can only find paperweight examples of this, where you can see that the object looks like it’s actually inside the glass.

To be clear, I don’t mean the ones where a **flat** image is engraved, but the ones where it looks like the object itself is inside the glass cube or rectangle!! Where you turn it and you can see all the different perspectives on the thing. I used to have one of these as a kid with an elephant inside, and it fascinates me how you could see it from underneath and all as though it were actually in the glass. I don’t understand how engraving works at all, but especially not like this in such a 3d way. Please help me understand if you can!

In: 3

They use lasers to sort of damage specific spots inside the glass.
They basically focus the lasers so that only specific spots are getting enough laser to damage the glass.

And because glass is clear those spots can be *inside* the glass.

It actually is a 3D image burned inside the glass.

It’s pretty neat. They do it with focused lasers. The laser gets focused down onto a super tiny point and pulsed for a very short period of time. As the laser passes through the glass it is heating it up a bit but the heat is spread out over an area and so isn’t enough to do anything except at the tiny point it’s focused at where the concentrated heat makes a tiny crack.

Repeat a bunch of times while moving the focal point around and you get a 3D pattern made up of tons of tiny little dots.

Neat video here for someone trying to sell one of the machines. You can just barely see the beam go from wider at the top to narrow where it’s marking.