Millimeter options


While FreeSewing supports millimeter options, we recommend using percentage options and will not accept contributions that use millimeter options.


A millimeter option should be a plain object with these properties:

  • mm : The default value in millimeters
  • min : The minimum that’s allowed
  • max : The maximum that’s allowed


options: {
  elasticWidth: { 
    mm:  35, 
    min:  5, 
    max: 80 
COMMENT by joost
What’s wrong with millimeter options?

Millimeter options do not scale. Parametric design is the raison d’être of FreeSewing and that core belief that things should seamlessly adapt goes out the window when you use a mm option because now you have a value that will not change based on the input measurements.

You could argue that it’s fine because you can just lower the option but that breaks the principle of sensible defaults (aka no surprises). The fact that you can sidestep the bullet does not mean you’re not creating a footgun.

When you need a millimeter option, reach for a snapped percentage option instead.