I hope that everyone who celebrates had a fabulous 4th of July. (I sure did!)

For this Fashion Friday, I wanted to talk a little bit about why the first release of CustomFit. I’ve gotten a few comments already about top-down raglans and whether CustomFit will produce them:

I knit top-down raglans. Will CustomFit work for me?
CustomFit works for everyone. But although we plan to change this in the future, it currently produces bottom-up patterns. You can choose between a pieced or (mostly) seamless construction. (Mostly seamless means the sweater is knit in the round to the armholes, then back-and-forth to the shoulders. The tops of the shoulders are seamed, and sleeves are worked top-down in the round. This produces a set-in-sleeve fit with only a few inches of simple seaming.)

Since I get a round of groans in every class when I suggest knitting a “pieced” sweater (whether you sew in the sleeves or pick them up and work top-down), I am absolutely, positively aware of how unpopular this garment construction is. A whole new generation of garment knitters have been brought into the sweater knitting fold with top-down raglans, and are loathe to switch.

Why that is, I don’t know exactly? But I think it probably has to do with the set-in construction seeming… daunting. There’s the seaming, maybe. Or short row sleeve caps, which are not exactly a simple-seeming alternative. There’s the apparent unpredictability of all of it: You don’t see whether your sweater works out until it’s finished. And emotionally, I think set-in-sleeves just feel so fussy and fashiony. What could be more attractive than the exact opposite of that?

I suspect that to anyone who was not brought to knitting specifically as a way to make clothing, it just seems… hard. Pointlessly hard.

…well, hard is relative, but it’s certainly not pointless. There are actually reasons for this fussy madness, and they relate directly to what CustomFit is trying to do. So let’s talk about the reason that trumps all others. I’ll start by talking about pieced sweaters, and revisit my “mostly seamless” option at the end.

A pieced, set-in-sleeve construction is the easiest to modify across all body types.

The importance of this cannot be overstated. If I want to produce software that will result in a perfectly-fitting garment for all women who come to use it, I must (must) start with a pieced construction. Here’s why. A well-fitting sweater will fit the wearer in the bust, cross-chest/shoulders, and sleeves. In a pieced construction, you have many degrees of freedom to achieve a good fit in those 3 areas fairly independently. I’ve marked them in green, here:


  1. Fitting the bust can be done by measuring it and multiplying it by your stitch gauge.
  2. Fitting the cross-chest can be easily achieved no matter how widely different the shoulders and bust are, because you can bind off many stitches if necessary.
  3. The bicep may be calculated independently of the shoulders and/or bust.

All of this is possible because the sleeve cap is where they all come together, and it can be solved for (largely) independently. The length of the bit marked in red must be the same length as the total armhole length (front and back) on the body. But while there are a few restrictions on how to shape the cap, as a designer (or a piece of software) you have lots of opportunity to make that length long or short, to match the body. And as long as they are the same length, the armhole and the sleeve cap can be done entirely differently.

Let’s contrast that with a typical top-down raglan construction:


It’s not that these sweaters are bad. They’re not. In fact, for those bodies they fit well, they’re pretty fantastic! The problem is that the red line here represents your opportunity, as a designer, to change the bust, cross-chest, and bicep–and you can’t fiddle with one without affecting the others.

There are a few things you can do. If you need a deeper armhole, you can increase every 3rd row instead of every other row. You could make the rate of body increase (the inside of the red line) slightly different than the rate of the sleeve increase (the outside of the red line)… but only slightly different. Try to get too fancy, and your fabric is going to pucker. Fundamentally, the way you make the bust larger is to make the sleeves larger and the armhole deeper. Period.

So if top-down raglans work for you, that’s completely and utterly awesome. But know that they don’t work (can’t work, even) for a large class of bodies. CustomFit has to work for every body. So it will start with a set-in sleeve construction, to give me the freedom I need to fit any woman’s shoulders, bust, and arms perfectly.

Thanks for sticking with me this far! A couple of more points.

  • A sweater that’s worn is always better than a sweater that sits in a basket awaiting seaming. This is why I’m offering the mostly seamless construction option. The math is fundamentally the same, and I have the same amount of freedom between those three crucial body points. But when you’re done with the sweater, you’re done! No seaming required except in the middle, and then only for the shoulders.
  • If you’re reluctant to knit a sweater this way because there is no security blanket of trying on the sweater as you go, fear not. CustomFit largely eliminates the need for that fear. It takes your body, and your gauge, and does all of the math for you. This results in a perfect fit without a single try-on.

I know that last one is hard to believe, because we’ve all gotten it so very wrong on at least one occasion. (Me too, by the way!). But I offer up the following as evidence:


This is a version of The Flutter Pullover, from the bookbut with a different neckline to better accommodate my body’s needs. It fits pretty well, right?



Here’s the cool thing about this sweater: I didn’t knit it. I had a few samples of book sweaters worked up to wear to classes and events, and this was one of them. Essentially, I gave my awesome sample knitter my measurements and gauge, and off she went. No try-ons, no eyeballing as I went.

It can work, I promise. And I hope that even if up until now you’ve been a die-hard top-down-raglan knitter, you’ll give another construction style a try.