About this project
A round coaster with a spill rim and engraved decoration. Set the diameter to the glass you actually use — the Info panel reports the flat centre you end up with, which is the number that matters.
Rim and recess
The rim catches condensation running off the glass. Its width comes out of the usable centre, so a wide rim on a small coaster leaves very little flat area — watch the usable-surface readout as you drag it.
The recess is the shallow dish inside the rim. It is clamped against the base thickness so it can never cut through, but the design check tells you when the clamp is doing the work rather than your setting.
Turn the rim off entirely for a flat disc.
Decoration
Three engraved treatments: concentric dimples, a spiral sunburst, or both at once. Each has its own controls, and they appear only when the style that uses them is selected.
Engraving depth is the one to keep modest. At 0.3 mm the pattern reads clearly and is still easy to wipe clean; much deeper and it collects whatever your glass drips into it.
Printing
Flat on the bed, no supports. The top face is the one you see, so if your printer has a textured sheet, print it upside down — the decoration is cut into the top, so that does not work here. Print it right way up and slow the top solid layers instead.
PLA is fine for cold drinks. For anything hot, PETG holds its shape where PLA will not.