Creating GROBS on a computer for HP50G?

[David Bengtson]

Does anyone have instructions on how to create GROBS on a Win10 computer? I'd like to have some small schematics in some programs as documentation, and drawing them on a computer seems to be an easy way to get a schematic. Hints on file formats, dimensions etc would be appreciated. I've found XnConvert, which purports to convert drawings to a GROB, but I haven't found any documentation.