Our Wikipedia, marking methods: 2.5D inner engraving

Internal laser engraving involves creating graphics (as well as texts) inside a glass or crystal element. The engraving made in this way is white and slightly translucent.

The technology of internal engraving involves focusing the laser beam in a specific point inside the glass. In the point of focus, a high power is released, causing microcracks in the material. Such a point is a kind of pixel, from which we build the image. We adjust the brightness of a given area of the graphic by the density of points and the number of layers.

The limitation of laser engraving is the shape of the glass figurine. Due to the very precise optics of engraving equipment, the surface through which the engraving is made must be perfectly flat and smooth. Any scratch or unevenness on the glass surface can disturb the laser beam and damage the final image in the glass.

2.5D Internal engraving is a specific variation of 3D engraving. However, it is used to create half 3D models from a photo of a person or a photo of any other object. The engraving technology does not differ from 3D engraving, but the way of preparing the computer model changes. In this process, the object has only a visible spherical front part, but lacks the rear element. Therefore, in the case of, for example, a face, we see a three-dimensional image of the visible part of the head in the photo, and there is no longer its back. This is because the 3D model process is based on converting any photo in bitmap form into a pseudo 3D object. This can be compared to overlaying a texture on the front part of a spatial object.