[Glossary entry]
First, a block is not a sloper (read this). A block is not a fitting shell either. Fitting shells are only used in schools, colleges, sewing classes, by custom clothiers or enthusiasts. Nobody else uses them. Yes I know, in school they have you make them but rest assured that once you leave school, you’ll never have to make them again unless you want to. Summarizing from past experience, I don’t want to arm wrestle with anybody over the pros and cons of whether you should use fitting shells, mostly because people assign themselves a lot of points for being able to do it and I think that is just great –really!-and I’m happy for you but I’d prefer that this entry not become a point of contention. Thanks.

A block is the pattern of a style that sells well for you. It sells so well for you that you use that pattern to generate new styles. If you are in the gestation of your line, you won’t have any real blocks because you haven’t sold anything yet. In such case, a block could be whatever pattern you’ve used to generate most of your products. It is the building block of your product line. Let’s call it a parent pattern. You use the parent pattern to generate styles from it or children.

A block pattern applies to any kind of sewn product (remember, it is not a fitting shell). If you’re making bags and have one style that consistently outperforms the others, that one should be your block. If people like that style, you should maximize your return by reusing an existing style that performs to generate new styles that will also -hopefully- perform as well as the block. Doing this takes out a lot of guesswork. We don’t need to reinvent the wheel each time, we base it on something. Style development takes a lot less time. A block is not a fitting shell because using a shell is like starting from zero. Previously I’d explained it thusly:

Now, the way we do it is to buy or use something that is similar to what we want to do and we fit that. Then we use a basic body -a block or an existing pattern, the fit of which we already like- and transfer to that, whatever the distinctive features of the new style. Plus, we make our fit changes. This way our first prototype will come out looking pretty good. For example, let’s say we’re making a coat. We are not going to start with a basic fitting shell. We will start with a coat pattern that we already have, that looks closest to the style we want to develop. That’s much different than how they teach you in school where everybody starts with a basic fitting shell. Fitting shells are pretty close to useless when it comes to style development; doing that, one will end up making a lot more iterations than we do. In real life, you’d be hard pressed to find a basic fitting shell pattern in the plant of any manufacturer. Beginners go from a “sloper” to coat incrementally. That’s a lot of work. Start with a coat. Make the changes, including fit. Then, bingo, you’re there. If you want to make a blouse, start with a blouse. Develop a basic range of styles that fit you and use them over and over again.

Now, before you go running off, there’s another entry on this topic you should read. It’s called PN Numbers. Long story but it describes the practical concerns of developing, using and managing blocks to save yourself a lot of money. A lot of money. It’s block pattern management. As you’ll learn, a block pattern system becomes a system of interchangeable parts (pattern pieces) and if you know that before you get too far into it, you can organize your pieces like parts, or a parts inventory from which you can make a whole lot of other styles that cost you very little. From the PN numbers entry are linkages to more entries in developing a pattern block system or network so read those too. Those entries will show you how to manage all of those small parts. This whole series (in my opinion) was one of the most valuable tutorials I’ve ever published on this site and it gets no love. There are links to diagrams you can print out, tons of photos illustrating block parent and child styles I’ve done as well as how to mark and manage each individual piece in the system. Then, this also has practical implications for working with your contractor because you have to know how to write up your cutter’s must and so on. If you want to read the series in order, it is:

How blocks work
What is Kaizen (don’t you dare miss this entry in spite of the title)
A cutter’s must
A cutter’s must pt 2
PN numbers

If I’ve left any out, please let me know. Trackbacking within system entries wasn’t live at the time so I may have missed one or two. Oh and if you’re still naming your styles rather than numbering them, be prepared for a lecture or two (sorry!). It is doubtful you’ll continue to do that if you read these entries.