Pattern configuration

This is about the pattern configuration file, used at build-time.

For run-time configuration, see Pattern settings.


name: "sorcha"

A string with the name of your pattern.


version: "0.3.1"


dependencies: {
  front: "back",
  sleeveplacket: ["sleeve", "cuff"]

An object of key-value pairs that controls the order in which pattern parts will get drafted.

See Part dependencies for more in-depth information on dependencies.


inject: {
  front: "back"

An object of key-value pairs of parts. The value part will be injected in the key part.

By injected we mean rather than starting out with a fresh part, you’ll get a part that has the points, paths, and snippets of the value part.

See Part inheritance for more in-depth information on inject.


hide: [

An array that lists pattern parts that should be hidden by default. Hidden means that they will be drafted, but not rendered. Typically used for a base part on which other parts are built.


parts: [

An array that lists your (additional) pattern parts. The name must be the key the object.

This does not need to be an exhaustive list of all parts in your pattern.

This list of parts is needed for the draft() method to figure out what parts need to be drafted. So if parts are included in the dependencies, inject, or hide configuration, there’s no need to include them here, as we already know of their existence.


measurements: [

An array with the names of the measurements required to draft this pattern.

Don’t just make up names

See freesewing models for a list of measurement names already used in freesewing patterns. It is a best practice to stick to these names.


Options come in 6 varities:

  • Constants : A value that can’t be changed
  • Booleans : A value that is either true or false
  • Percentages : A value in percent, with minimum and maximum values
  • Millimeters : A value in millimeter, with minimum and maximum values
  • Degrees : A value in degrees, with minimum and maximum values
  • Counters : An integer value, with minimum and maximum values
  • Lists : A list of options with a default

Under the hood, millimeters, degrees, and counters are handled the same way. We use different types because it easier to understand the nature of a given option.


If your option is a scalar value (like a string or a number), it will be treated as a constant:

options: {
  collarFactor: 4.8

Rather than define constants in your code, it’s good practice to set them in your configuration file. This way, people who extend your pattern can change them if they would like to.


If your option is either true or `false, or on or off or yes or no, you can use a boolean:

Your boolean option should be an object with these properties:

  • bool : Either true or false which will be the default
options: {
  withLining: { bool: true }


Percentage options are the bread and butter of freesewing. Almost all your options will probably be percentages. They make sure that your pattern will scale regardless of size, and pass the ant-man test.

Your percentage option should be an object with these properties:

  • pct : The percentage
  • min : The minimul that’s allowed
  • max : The maximum that’s allowed
options: {
  acrossBackFactor: { 
    pct:  97, 
    min:  93, 
    max: 100 
Percentage options will be divided by 100 when loaded

You specify percentages in your config file. For example, 50 means 50%. When your configuration is loaded, those percentages will by divided by 100.

So a percentage of 50 in your config file will be 0.5 when you read out that option in your pattern.


While we recommend using percentages where possible, sometimes that doesn’t make sense.
For those cases, you can use millimeters.

Your millimeter option should be an object with these properties:

  • mm : The default value in millimeter
  • min : The minimul that’s allowed
  • max : The maximum that’s allowed
options: {
  elasticWidth: { 
    mm:  35, 
    min:  5, 
    max: 80 


For angles, use degrees.

Your degree option should be an object with these properties:

  • deg : The default value in degrees
  • min : The minimul that’s allowed
  • max : The maximum that’s allowed
options: {
  collarAngle: { 
    deg:  85, 
    min:  60 
    max: 130 


For a given number of things, use counters. Counters are for integers only. Things like number of buttons and so on.

Your counter option should be an object with these properties:

  • count : The default integer value
  • min : The minimal integer value that’s allowed
  • max : The maximum integer value that’s allowed
options: {
  butttons: { 
    count: 7, 
    min:   4,
    max:  12 


Use a list option when you want to offer an array of choices.

Your list option should be an object with these properties:

  • dflt : The default for this option
  • list : An array of available values options
options: {
  cuffStyle: { 
    dflt: "angledBarrelCuff",
    list: [


Patterns also take these configuration options to facilitate frontend integration:


The name of the designer:

design: "Joost De Cock"


The name of the developer:

code: "Joost De Cock"


Either pattern or block.

type: "pattern"


A 1 to 5 difficulty score that indicates how hard it is to make the pattern:

difficulty: 3


A set of tags to allow filtering of patterns on the website:

tags: ["underwear", "top", "basics"],


Organises your pattern options in groups. It expects an object where the key is the group title, and the value an array of options:

optionGroups: {
  fit: ["chestEase", "hipsEase", "stretchFactor"],
  style: [

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