With the basic outline of your pattern ready, now would be a good time to test it to see how well it adapts to different measurements, and the range of options we provided.

No more grading

FreeSewing patterns are made-to-measure, which means that you don’t need to grade your pattern to provide a range of sizes. You should sample your pattern for different measurements and options to see how well it adapts.

If testing your pattern sounds like a lot of work, you’re in luck. FreeSewing can do it for you. Click the Test your pattern button in the top navigation bar of your development environment, and you’ll see a number of choices at the right:

  • Test pattern options
  • Test measurements
  • Test models

The API docs on sampling have all the details on how this works, but for now we’ll just look at the end result of each of these.

Testing pattern options

We used percentage options, which can vary between their minimum and maximum value. For these tests, FreeSewing will divide that range into 10 steps and draft your pattern for each step.

Click on any of the options we’ve added to our pattern, and your bib will be drawn with that option sampled.


The lengthRatio option controls the length of our bib. Testing it confirms that it only influences the length:

Your bib with the lengthRatio option sampled


The neckRatio option will determine the size of the neck opening. For a the same headCircumference measurement, varying this option should result in bibs with increasingly larger neck opening.

Testing it confirms this. We can also see that as the neck opening gets smaller, we will rotate the straps further out of the way to avoid overlap:

Your bib with the neckRatio option sampled


The widthRatio option will determine the width of our bib. For a the same headCircumference measurement, varying this option should result in increasingly wider bibs.

If we test it, we can see that it works as intended. But there’s one thing that perhaps requires your attention. Making the bib wider shortens the length from the bottom of the neck opening to the bottom of the bib. Thereby making the bib shortern when its worn.

Even if the total length of the bib stays the same, the useable length shortens when the bib is made wider. Users will not expect this, so it’s something that we should fix in our pattern.

Adjusting the pattern to make the widthRatio not influence the useable length of the bib is not covered in this tutorial. It is left as an exercise to the reader.

Your bib with the widthRatio option sampled

Testing measurements

Testing a measurement will vary that measurement 10% up or down while leaving everything else the same. This gives you the option to determine how any given measurement is influencing the pattern.

For our bib, we only use one measurement, so it influences the entire pattern:

Your bib with the head circumference measurement sampled

Testing models

Whereas testing a measurement will only vary one individual measurement, testing models will draft your pattern for different sets of measurments, which we refer to as models.

On the surface, the result below is the same as our measurement test. But that is because our bib only uses one measurement. So testing that one measurement ends up being the same as testing a complete set of measurements.

But most patterns use multiple measurements, and you’ll find this test gives you insight into how your pattern will adapt to differently sizes bodies.

Your bib sampled for a range of baby sizes

The antman test

A special case of model testing is the so-called antman test. It drafts your pattern with a set of typical measurements , and then drafts it again with measurements that are 1/10th of those typical measurements.

It is named after the cartoon character who can shrink, yet somehow his suit still fits.

The purpose of the antman test is to bring out areas in your pattern where you made assumptions that will not properly scale. Many drafting books will tell you to add 3cm there or measure 2 inch to the right. Those instructions don’t scale, and you should avoid them.

The best patterns will pass the antman test with 2 exact pattern. One will simply be 1/10th the scale of the other.

Congratulations, your bib passes the antman test

When you’re happy with how your pattern passes these tests, it’s time to complete it.