freesewing/markdown/dev/tutorials/pattern-design/adding-measurements/en.md

title	order
Adding measurements	130

FreeSewing is all about made-to-measure sewing patterns; we are going to draft our pattern according to the measurements provided to us.

Which begs the question, which measurements?

It is we, as the pattern designers, who decide which measurements are used to draft our pattern. For our bib, the only measurement we need is the head circumference.

So let's add it as a required measurement.

Adding required measurements

In our design/src/bib.mjs file, on the bib object, there is a key called measurements (line 121) that will hold a list (an array) of all required measurements for this part.

We are going to use the official name of the measurement. For head circumference, that name is head.

function draftBib({ part }) {
  return part
}

export const bib = {
  name: 'tutorial.bib',
  draft: draftBib,
  from: false,
  hide: {
    self: false,
    from: false,
    after: false
  },
  options: {},
  // start-highlight
  measurements: ['head'],
   // end-highlight
  optionalMeasurements: [],
  plugins: []
}

Now everybody knows this part requires the head measurement.

This change will also get picked up by the development environment, and we'll now see this screen:

Since it's just one measurement, let's simply enter a value by hand. For example 38 as 38 cm is a realistic head circumference measurement for a baby.

Enter 38 in the box, and click on Draft Design in the sidebar under the View heading. This brings us back to our work in progress:

Notes

Why using standard measurements names matters

In principle, we can use any name we want for our measurements. Our core library really doesn't care.

However, if everybody uses their own (names for) measurements, then people aren't able to re-use their measurements across designs.

So if you have any intention at all to play nice with the FreeSewing ecosystem, please make sure to re-use the names of existing measurements, rather than invent your own.

See our best practices on this topic for details.