A master block is the base from which garments are designed and produced. To develop a master block, construction lines are used in the drafting process. The final block is then created from the draft. A master block does not have design lines, intricate detailing, extension lines or seam allowances. As well as being the base from which garments are made, it is used to produce additional blocks for specific garment styles, and blocks for specific figure types and body shapes. Master blocks are also referred to as a basic block, sloper, or foundation pattern (other terms are also used). An industry convention is that master blocks are never cut up or used for an intermediate pattern: a copy of the master block is made for pattern making and design purposes. A good set of tested and well fitting master blocks usually consists of: a bodice; sleeve; dress; skirt and pant, which are a designer’s and pattern maker’s most treasured assets.
A list of additional blocks that can be produced in preparation for drafting specific garments, can be found in The Fashion Design System (Berry and Hennes, 2008).
Master blocks can be drafted manually or generated on a computer using a set of measurements taken from an individual (yourself, a client or a fit model), or an arbitrarily chosen set of average measurements representing the standard sized figure in a specific target market. Once the fit of a master block has been tested on a muslin or toile and any necessary adjustments made, the changes are transferred to the master block which is then ready for use in the pattern making process. When blocks are used manually, they are reproduced in a material such as medium weight cardboard, plastic, or leather. Alternatively, blocks are saved and stored in a computer, and retrieved when necessary for design purposes (don’t forget to back up your computer data)!!