My wife has a Bernina embroidery machine and I'd like to experiment with creating designs programmatically. I'd like to either find out how to output data in a format the machine's software will accept, or else find a free or inexpensive utility that can convert from a format I can produce (such as HPGL, or something else documented) to a format the machine can accept. My intention would be to output a file with one XY coordinate per stitch, plus instructions to change thread (pause for thread change); I don't need something to generate area fills, adjust stitch spacing, optimize stitching order, etc.; I'd expect to handle those things myself.
Anyone have any suggestions?
Bernina's .ART format is indeed proprietary, but Berinina owns a software company, OESD, that makes conversion software (e.g. the OESD Magic Box). You can create files using a documented file format, such as .PES, and use their software to convert the PES files into ART.
Here's a resource on the layout of some of the embroidery file formats
disclaimer: the company I work for sells OESD products.