Monday, October 11, 2010

Drafting Part XIII - Using Slopers With Commercial Patterns

We're close to wrapping up our series on drafting! We took a nice break to do a lot of actual sewing and now we're back! Today Jen will guide you into the world of commercial patterns, and teach you how to customize them to better fit you or the child for whom you're sewing. Neither Jen nor I use commercial patterns much, if at all, but we know how they work (or don't): the mystifying symbols, the seam allowances (why? why?), the ostensibly "standard" fit, the undecipherable tables of measurements, the unknown (until you've turned them into a garment) ease...... oh wait, that's
my inner whiner bleating.

With a little bit of the right kind of information, though, commercial patterns are a very good starting point for garment-making. If you are lucky, you might have found a manufacturer or pattern company whose patterns fit you better than most with hardly any adjustment. If you have an especially unusual body shape, you might have given up on commercial patterns altogether. However, if you're like most of us, you've probably got a collection of working patterns from different sources, some of which need more work than others to fit. Want some help?

In this comprehensive deconstruction of commercial patterns, Jen will take you through:
  • determining which pattern size to use
  • determining and adjusting the amount of ease
  • working with seam allowances
  • adjusting different kinds of patterns - dresses, skirts, sleeves
  • adjusting different elements of the pattern design - necklines, hems, shoulder slopes and design fullness (like gathers).

Here's Jen!

Now that you have a ready and wearable sloper / bodice block, you can adapt it to make any style of dresses, blouses and skirts, limited only by your imagination. If that task seems daunting to you, then use it to make commercial patterns fit your child as though you've drafted them yourself. Hey you took the time and effort to create a good-fit sloper, so you may as well make the MOST of it.


Getting Started




finished measurement - sized measurement = pattern ease (style and/or fit)
22 - 21 = 1

Write these numbers down somewhere on the back of the envelope so you will always have it on hand. The difference is the amount of ease built into the pattern. If you have included ease (e.g. 0.5") into your sloper (chest, waist, hip), take that much away from the ease calculated for the pattern.

pattern ease - ease included in your sloper
= amount of ease to add back into the pattern after adjusting

1 - 0.5 = 0.5



Adjusting the Commercial Pattern



Determine the seam allowance in the commercial pattern as explained above.



1 Upper torso
Place your sloper on the pattern matching the chest line, or waist line (this is dependent on the design of the dress) of the sloper and the pattern. Trace out your sloper onto the pattern itself. Take the sloper away after tracing.
From the traced chest line (or waist line if you've used that) add in the amount of ease given for the chest (or waist) minus the ease from your own sloper (0.5" in the worked example above) and mark this with a point on the pattern. I will call this point (A) for reference later.

To lengthen
To shorten: crease the pattern along the drawn line and make a pleat according to the amount to decrease. Place the sloper over to check. Tape the pleat down and redraw the scye smoothly.
You are done with the upper torso.

2 Skirt
the skirt portion of the skirt will start from either the chest or waist line (design dependent). You would already have adjusted the pattern at the upper torso according to either one, as explained previously. Adjust the waist (chest) of the skirt like so:

You must either add to or subtract X from the chest/waist line of the skirt piece. You
  • add if you had to increase the chest/waist line in the upper torso or
  • subtract if you had to decrease the chest/waist line in the upper torso.
Redraw the side seam.

You are done with the skirt portion.

3 Sleeve
because sleeves can vary in style, I will only explain how to adjust the depth of scye of the sleeve, which in most cases is sufficient to ensure a nice-fitting sleeve. On the commercial pattern, draw a line to join the 2 points marking the base of the armscye.






Redraw the side seams.

You are done with the sleeve.

4 Sheaths -


Other Areas to Consider

If the difference is negligible, then don't bother adjusting, really. *remember that on a sleeveless pattern, the shoulder point should sit higher on the shoulder line (see here for more explanation). For a sleeveless pattern, mark a point about 3/8" (1 cm) in from the original point. Use this new point as the reference when adjusting the shoulder slope.


3 Sheath / Skirt length

Design Elements to Consider


Last Words

All the adjustments taken above are required for both Front and Back pieces. Adjustments are not necessary for embellishments like sashes, lace trims, binding, because you will only need to increase the amount required by a little bit. Fabric yardage can remain the same as well because the pattern writers tend to state more than is usually required.

I hope this provides you with the verve to go out and alter all the commercial patterns in your collection. If you are anything like me, quite a few were really ill-advised, I bet!

LiEr back again:
Told you she was good! Yes, there is hope for all the children of the world who are between sizes, taller than average, huskier than average - which is most of them. Even I want to go out and buy a pattern just to play around with my slopers! The good news about children's patterns is that they are easy to alter and customize to your small person's unique dimensions.

What about adults?
The principles are the same - you match the reference lines of your sloper to those of the pattern. Often, as Jen says, this means you pick the
most defining reference line for that kind of garment (e.g. the bust), and adjust the others on the pattern (e.g. the waist, the shoulder point, the hip etc) to match your sloper. There are darts in an adult female pattern, too, so you'll be adjusting those as well. And then, make a muslin and try it out!

Next up: A wrap-up, a summary and a giveaway!


  1. Burda patterns are made without seam allowance added in, and Americans are always complaining about that. If I remember correctly from my high school sewing ventures, European patterns never have seam allowance added in; it's just the Burda ones that have made it across the ocean...

  2. Well hurrah for European patterns, then!

    I suppose if a person grows up being exposed to inbuilt seam allowances, they get used to always having them, just as I have gotten used to not seeing/having/using them. To each his/her own, I guess. Just not mine.

  3. I linked to your tutorial over at Craft Gossip Sewing:

    I agree about seam allowances! When I first started sewing, I only used patterns that had them built in and it was inconceivable that I'd ever want a pattern without them. But once I started using some Burda patterns and creating my own patterns, I got used to the flexibility of adding my own allowances.

  4. Hi thanks for all these wonderful tutes on drafting etc. Up until I read your blog drafting princess seams had mystified me. Now you go a wonderful step further and teach me how to use my sloper to fit commercial patterns. Finally I will get some value out of my pattern collection!

  5. "pattern ease - ease included in your sloper
    = amount of ease to add back into the pattern after adjusting

    1 - 0.5 = 0.5"

    But then later the example has 0.5 inches added to the half of the front, which would mean really adding 1 inch to the front, and presumably another inch to the back. Shouldn't the ease be divided up between those 4, so 0.125 inches to each quarter of the garment?

