How we picked
Each tool had to be genuinely free, accept a standard photo, show a backlit preview before downloading, and export a watertight STL.
Tip: Use white PLA with 100% infill and 0.08–0.12 mm layers for the sharpest result. The thinner the layers, the more tonal detail the lithophane reveals.
Disclosure: AVDEB is our own tool, so we've placed it first for convenience. Every other pick was judged on the same criteria.
