In the not too distant past, engraving images and words mostly onto metal was done by hand using a burin that cut grooves into whatever surface was being used.
In an attempt to mechanize the process a Pantograph was invented that would trace a larger letterform master and simultaneously cut those tracings into scaled down duplicates onto metal. In time the engraving tip was mechanized using a motor to spin a cutter that would carve the letters into metal as it traced the master by hand.
This process was ultimately computerized with the cutter following paths created in a file using special software. That final step became known as mechanical or rotary engraving. Eventually, new materials were developed such as laminated acrylic sheets, making it possible to not only cut into the surface of the material, but cut through to a contrasting substrate thereby expanding its capabilities and uses.
At the same time a wide range of cutters were being developed to carry out varying tasks on a variety of materials including glass. Larger engraving beds helped to increase production and made larger work possible. Specialized adapters allowed these machines to engrave on curved surfaces such as bowls, cups, glassware, etc.
The dimensional image and lettering were achieved using a rotary engraver in this design by Jim Sadler.
The computer software also improved along with the computers themselves, making the graphic and typographic capabilities much greater. All of this laid the foundation for the use of lasers to burn into and cut through materials, however, rotary engraving still remains a viable and useful process for many applications.