Pattern Drafting + Grading Basics

One of our goals for 2016 is a commitment to partner with some of our pals in the sewing community to bring you guest features on garment sewing, since that is not an area we currently focus on at Sew4Home (you never know what the future will bring). Garments generally require complex, multi-piece patterns in a variety of sizes, which sounds intimidating – right? Carla Crim, from Scientific Seamstress and Jennifer Paganelli’s Sis Boom eBooks and ePatterns, is here to help demystify the process of creating the patterns that come together to make something beautiful to wear. We found the techniques fascinating, and it certainly inspired us to give it a try. 

Carla’s tutorial originally appeared on SewMamaSew (our creative neighbors and friends out here in the Pacific Northwest). Thanks, Kristin for allowing us to share the information with our Sew4Home visitors!

Hi, my name is Carla Crim, and I’m the patternmaker behind Scientific Seamstress and Sis Boom eBooks and ePatterns. Nearly a decade ago, I left a career as a research scientist to stay home with my infant son. To help make ends meet, I designed and sold one-of-a-kind ensembles for collector dolls on eBay. This evolved into making and selling simple ePatterns for American Girl® dolls. From there, I transitioned into children’s patterns, and a few years later, teamed up with popular fabric designer, Jennifer Paganelli and her Sis Boom enterprise to make patterns for kids and adults.

Like many ePatternmakers, I am completely self-taught, using books and internet resources. I get lots of emails asking: “What patternmaking software do you use?” The truth is, I don’t use patternmaking software at all. I did a little research when I first started out, and found commercial versions were WAY out of my price range. The more affordable, user-friendly versions are for home use only (which is fine if you are making patterns for yourself, but you can’t sell them). My patterns are actually made using good, old-fashioned drafting techniques and outdated presentation software. I know I could probably justify splurging on commercial software at this point, but you know what?– I don’t even want it!

First off, I know there would be a huge learning curve as with any advanced, highly-specialized software. Most importantly though, I’ve come to think of my patterns as a handmade product. Lots of time and love go into them, and I’m proud of the fact that my two hands touch each size of every design (even though it is via a keyboard to a great degree). In this article, I’m going to discuss the resources I used to learn how to draft patterns and the tools I rely on to ensure accuracy.

Carla’s pattern making studio

Making the initial pattern can be done by draping, flat drafting, or a combination of both. When I designed patterns for dolls, I did everything by draping. I would hold up little pieces of muslin or tissue (paper towels work great too) to the doll, then manipulate and cut to fit. She would hold perfectly still, and she didn’t mind if I occasionally jabbed her with a pin. After trial and error, I would get just the fit I wanted, and would then proceed to computer import. I knew that if the pattern fit my doll, it would fit every doll just like her (life was so simple then… sigh). I don’t do that much draping for human clothing. I do have a vintage adjustable dress form, but she is a bit warped and missing a few parts. Plus, I tend to stick to basic, free-fitting designs that are very suited to flat drafting. If you want to learn more about draping, there are dozens of textbooks on the subject. One I like is Draping for Apparel Design by Helen Joseph-Armstrong. You could also just watch endless episodes of Project Runway and learn by osmosis.

My first multi-sized pattern for girls was the Patchwork Twirl Skirt. Sizing was really simple because its elasticized waistband was all that needed to fit to the body, and length determination (waist to knee) was very straightforward.

Carla’s Patchwork Twirl Skirt

After that, I did my Stripwork Jumper. It has a very basic bib-style bodice with straps, which was something I had made over and over for my doll patterns. I made the prototype to fit my then two-year-old son, using the draping process I described above. It fit like a size two should, and he looked cute as a button twirling around in it. But what about the other sizes? I was pretty confident about what should happen with girth just based on the sizing charts I had found online. But what about the length of the bodice? And how deep should the armholes be? And what about the straps? ACK! After lots of trial and error (mostly studying size charts, measuring finished garments, and getting fit feedback from friends), I drew up bodice patterns in sizes 6 months to 8 years. They worked out great, but if I had known then about flat pattern drafting, I could have saved weeks of effort.

Carla’s Stripwork Jumper

Flat pattern drafting is based around two-dimensional renditions of the human form called “slopers.” Slopers are basically patterns that, when put edge to edge (no seam allowances included), would fit the body exactly. I’ve also seen them referred to as “second skins.”

Slopers are drawn using a set of measurements (standard or custom) and a series of calculations. Don’t be intimidated; it’s easier than it sounds if you just take it step-by-step. I’ve actually drawn a couple of bodice and pants slopers from scratch, and I have to say it was a good exercise and I’m glad I understand and appreciate the process. However, it is a lot of work and there is always the chance of making one tiny mistake and messing up the sloper (and all subsequent patterns based on it). Luckily, there is a great company in Canada called String Codes Designs that sells standard and customized slopers to the pattern making community – that means they are yours to trace and modify as you please! They are computer generated and printed on large format paper, and they contain all the detailed measurements that were used to generate them. They come in toddler through plus sizes, and you get a big discount if you purchase multiple sizes in a group.

A bodice sloper with sleeve

So how does one go from sloper to usable pattern? In a nutshell, it’s all about adding length or width to different spots to get the fit you want. Ease is a term I’m sure most of you are familiar with; it’s what makes a garment wearable and not skin-tight and constricting. “Wearing ease” is the amount of excess needed so you can walk around and move comfortably (I think some of the skirts I wore in college lacked this). “Design ease” is the excess beyond wearing ease to give a garment its specific look: fitted, semi-fitted, loose fitting, etc. Again, this is a subject on which entire textbooks have been written. I own Patternmaking for Fashion Design by Helen Joseph-Armstrong. It has good instructions for drafting lots of different styles for both adults and children, and it’s a good general reference to have on hand since it also covers lots of other neat details, like drawing collars and cuffs.

The A-line Tops and Dresses pattern was my first foray into flat pattern drafting.

Carla’s A-line Top

Below is a little recreation of how I drew the bodice front piece for each size. First, I traced around the top and side edges of the sloper (because of the style, I didn’t need to worry about the bottom edge or the darts).

Then, keeping in mind the amount of ease I wanted and the placement on the shoulders, I drew the outline of the garment edges.

After that, I added in the seam allowance. Keep in mind that this is just the pattern draft. If selling the pattern, the finished version would be electronically rendered and much neater!

At first, it was a little hard to envision that flat piece of paper as representing a human figure, but I got used to it over time. I’ve used this technique for all my child-sized patterns, even for more complex designs like the Bowling Shirt and Precious Dresses.

Three sizes of Carla’s Precious Dresses with different collar, sleeve, and bodice options

I like to flat draft toddler, child, and tween sizes individually, because the proportions change so much as children grow. Once you have a good fit at one size, however, grading can be used to make a few smaller and larger sizes.

Before I get into grading, I want to talk a bit about measurement charts. Just about every clothing company has the basic measurements (chest, waist, and sometimes hips) they use for sizing posted online. This is a good starting point if you’re doing simple things like skirts. More detailed charts that give vertical measurements (waist to knee and waist to ankle for example) and additional girth measurements (like neck and wrist) can be found scattered about the internet and are also compiled in many sewing and pattern making books.

The ultimate source for detailed sizing charts is ASTM International. These folks come up with standards for everything from the electrophoretic mobility of proteins to the retackablility of carpet adhesives. They offer separate size charts for infants/toddlers, children, women, plus-sized women, men, and probably dogs and cats. These standards are $30-$50 to download, but it’s well worth the investment if you plan to get into the pattern making business. The science geek in me loves the comprehensive nature of these documents. You can even get complete diagrams of the different body measurements.

ASTM standard chart taped near my computer for quick reference

OK, back to grading. As the human body grows (up or out as the case may be), different parts of the garment need to expand to different degrees. In other words, you can’t just enlarge a size 2 on a copier and make it fit a 20. That is why the size chart is so important. It tells you exactly how much each part of the body changes from size to size.

Grading is something that can be contracted out. This article from Fashion Incubator is geared towards fashion designers, but gives some good information on hiring a grader.

I like to do my own grading, because 1) I’m a control freak, and 2) it’s actually pretty fun. This article from Threads Magazine gives a great explanation of two different methods. I use the pattern shifting method, but I do it right in my drawing software rather than with actual pencil and paper. If you are just starting out, I recommend doing it as described in the article. Then, as you become more comfortable with digital drawing, you can replicate the same process on the computer screen, saving you from having to scan so many pieces.

If I am doing a multi-sized pattern, I usually start out with a single, middle-of-the-range size for a “group” of patterns. For example, I’ll flat draft a Misses’ size 6, and then I’ll grade it up and down to 4 and 8 (and possibly a size 2 and a size 10 depending on the complexity of the design). Of course, before you go to the work of grading, it is important to make sure the original size is a good fit.

It is very helpful if you have access to a live person who is this size (called fit models in the trade). Dress forms are great, but they don’t move and they lack limbs. I’m a medium size on most days, so I usually make something that fits me first (bonus: I have something new and pretty to wear). For kids’ clothes, my son is a great test size, but I find it harder and harder to get him put on dresses. Imagine that! Whichever way you choose to test your original, once you get that first size just perfect, you can go ahead and grade up and down a size. After grading, I measure the pattern piece to make sure the right amount was added or subtracted. If I’m grading several sizes, I also like to “nest” them by aligning all of them at a top or bottom corner to make sure they are increasing or decreasing as expected.

Some nested bodices

The ultimate test of whether or not grading has worked out is to sew up a sample and see if it fits someone (or a dressform) of that size. Sometimes I’m jealous of people who have lots of kids to use as fit models (but then I remember they have to feed them and do their laundry). Luckily, I have a big group of friends and family who are more than happy to trade a sewn item for pictures and detailed feedback on fit.

Thanks for joining me for a little introductory lesson on drafting and grading. And, thanks to Sew4Home for spreading the word about how fun it can be. I hope you’ll give it a try!

Cute neighbor kid in the Sis Boom Marissa Dress

Our thanks again to Carla Crim, Jennifer Paganelli, and all our creative friends at Sis Boom. And, be watching for new projects we have coming up in Jennifer’s latest fabric collections for FreeSpirit Fabrics. We absolutely love designing with her lush colors and detailed motifs.