Corset Patterning from Scratch:
The Basic Toolkit & Underbust Drafting Tutorial

Simple underbust corsets are a staple for corset wearers, and therefore corset makers. This tutorial will cover the patternmaking tools and techniques to get you started. The underbust design I am demonstrating is about the same length all the way around (no extreme points or longline shaping), and has twelve vertical pattern pieces.

 (Updated 6/21/12 with clarified drafting instructions)

Tools

A wide assortment of rulers and curved rulers are available for patternmaking. Which tools you reach for will ultimately depend on your personal preference and the task at hand. Below is a list of the most commonly used tools, with some notes about what I use each one for and which are my favorites.

First off, there are the rulers and various curve/straightedges. I've only listed and described tools which I have personally owned/used; obviously there's a further array of options available and many variations on those listed below.

Clear Plastic Ruler If pressed, I could literally draft a pattern with this, and only this, ruler. Common sizes are 2x18”, 2x24”, 1x6” and 1x12”. Some versions have centimeters running down one side and a fractioned inch grid on the other; others are 1/8” grids all the way across with 1/16”s marked down the very edges. The grid enables you to create seam allowance or mark parallel edges and the flexibility helps you measure curved edges. Do NOT leave this in your car in the sunlight; they can and will warp if bent too hard or exposed to too much heat. They can also snap, although are fairly giving and thus travel well in a purse or messenger bag, depending on the size.
Fairgate Vary Form Curve 24” My second favorite ruler, a calibrated curved edge with an armhole-like curve at one end. The length gives you a wide variety of curves and the calibrated edge makes it easy to mirror or replicate a curve.
Hip Curve Another curved ruler, this one with a shallow curve and squared-off ends. I believe I originally got this for a menswear course in the course of my BFA in fashion design. Because the curve is shallower and more uniform, I rarely find myself reaching for this ruler, and I wouldn't recommend it for a corsetiere.
French Curve This small, tight curve is excellent for armholes, sweetheart necklines, and the upside down sweetheart often found at the center back of longline corsets. However, it has weaknesses too: because it's plastic, it can break (though metal curves can also bend and become difficult to lay flat); it is clear plastic and therefore easy to lose in plain sight; it is not calibrated, making it  difficult to recreate matching curves.
L-Square Exactly what it sounds like. An L-shaped ruler for creating perpendicular, or squared, lines. Because of the cast shadow from the metal edge, I find them a bit difficult to align and am more likely to use the grid on my dot paper or my clear plastic ruler to create perpendicular lines. However, many patternmakers find them essential – your milage may vary and I recommend you try this tool as it is a standard piece of equipment.
Pattern Master The pattern master combines many tools into one and it is my go-to tool for traveling. Made of sturdy clear plastic, it contains a straightedge, a hip curve, and a small french curve cutout. It is available in centimeters or inches. As an American, I have the version marked in inches. Both the curved edge and the french curve are handily marked with 1/4” and 1/2” seam allowance; the straightedge has 1/4” markings up to 2 1/2”, and the interior contains various perpendicular and 45º (bias) line guides. I often use this for cutting my binding, as the straightedge is beveled and thus easier to guide a rotary cutter along without accidentally ruining the edge with notching. Difficulties are that all the edges are shorter than on their full-fledged counterparts, there are no guidelines for 1/8” markers (though they are on the calibrated edges), and the numbering on the straightedge starts at the center and goes to 8 at either end, making it awkward to use as a measuring tool.

Aside from rulers, obviously there are many other tools necessary for drafting.

A Large Flat Surface I know, it seems obvious. I've been known to draft on small trays or the back of my sketchbook, but it's bad form and only makes your life harder; I don't recommend it. When at my studio, I draft patterns on my cutting table which is easily overrun with fabrics, previous patterns, and tools, so try to keep your space organized to make sure you have room to spread out and be tidy.
Pattern Paper Technically you can use any paper. Butcher paper will do. However, if there's a tool for the job, it's often worth it to invest and use it. Pattern paper is lightweight with a numbered and/or lettered grid that is ideal for creating parallel and perpendicular lines, although you should double-check the calibration with your ruler for precision. The thickness is somewhat important because ideally it should be light enough for you to see through to duplicate lines. A roll of pattern paper will last you a very long time; it's been four years since I picked up my roll and there's still a reasonable amount left on it.
Tracing Paper For smaller patterns, I might use tracing paper to make corrections because it's easier to see through, but it's a lot more delicate so I wouldn't use it for a first or final pattern. A 14x17” pad is a good size.
Tag Paper Or tagboard or manilla paper. This heavyweight paper is for final patterns or seam allowance-free blocks which will get used heavily for tracing or cutting. Don't cut anything out in tag paper until you believe yourself to be done with mockups, prototypes, and corrections.
Paper Scissors I'm sure you know not to use your fabric scissors for paper, but it's also helpful to keep your pattern scissors separate from your house/craft scissors that cut sticky things, plastic packaging, cardboard, whatever.
Drafting Pencil I find it extremely difficult to draft an accurate pattern with a standard pencil or regular mechanical pencil. The lines are too thick and/or irregular, and the pencil stands away from your straightedge, adding fractions of inches to each line you make. You have to start with accurate patterns to sew accurate corsets. My preferred pencil is a .4 GraphGear 500 by Pentel with regular HB lead. .5 is also fine. .3 lead breaks too easily for my heavy hand and .7 is too heavy a line; try experimenting to find your favorite weight of lead. The downside to a .4 is that I have to go to Japantown to buy lead refills; .5 can be purchased most anywhere and even .3 is easier to find.
Pattern Notcher A notcher is a tool that is superficially similar to a hole punch, but it creates a notch perpendicular to the cut edge of a pattern. The notches are used to align pattern pieces and ease placement, indicate key spots in the pattern (such as the corset waistline), and in production garment patterns, mark seam allowance.
Click Eraser A skinny eraser in a mechanical-pencil-like casing, good for erasing small areas, especially line corrections.
Large Plastic Eraser Good for erasing large areas.
Scotch Tape / Sellotape I buy 3/4” wide Scotch tape and cut it in half lengthwise. You'll often need this to add seam allowance and make corrections. I save a lot of pattern paper scraps and tape them onto my patterns when I need to do this. You might also want to tape patterns in place as you trace them to make corrections or variations.
Tracing Wheel Another popular tool that I'm not particularly fond of, in large part because of its propensity for stabbing me. Use this to transfer lines from one piece of paper (or a muslin drape) to a paper below. I personally find it challenging to use this tool with much accuracy, especially since its pinprick holes are a bit challenging to see, but obviously you can always true the lines after the fact. I tend to stab through a muslin with my drafting pencil or trace from my pattern paper. Again, this is a common/standard tool and I recommend you give it a shot before disregarding it based on my bias and idiosyncrasies.
Light Box/Light Table This tool is optional but if you have the money and space for it, it can make line or pattern piece transfers, as well as edge truing, much easier. The only downside is that sometimes it is so efficient that it's difficult to tell whether a line has already been traced or is just shining through clearly from below.

How to Take Measurements

Before you take measurements, be sure you are adequately prepared and know how to take them accurately.

• Tie a piece of elastic around the waist to keep a clear reference point. While many use ribbon or string to mark the waist, I think elastic is better because it automatically rolls to the smallest point and will neither sag nor cut in if tied with the appropriate tension. (I realize this benefit is slightly skewed on the apple bodied type, for whom the natural waistline may not be the smallest point, but I still think it is frequently more helpful than a ribbon.)
  
  
• I stand, and direct clients and models to stand, with “good” posture (back straight, pelvis tucked, shoulders back) and my core muscles slightly engaged. I want my corsets to encourage good posture, and the slight engagement of stomach muscles is a medium between a forcibly sucked in and a slack, distended belly, as well as a mimicry of the tension of your core pushing against the structure of the corset.
  
  
• Try to keep the measuring tape parallel to the ground all the way around when taking circumference measurements. If it slips off this track, the measurement will be inaccurate. This is particularly likely to happen for the underbust measurement, and, for other patterns, the full bust.
  
  
• The subject should be wearing no clothing over their bra and panties. The bra band and straps should be tightened appropriately, otherwise it can skew your vertical measurements.
  
  

Measurements for Underbust Corset Drafting

A. Underbust circumference, at bra band level/top edge of corset

B1. Natural waist, for reference only

B2. Desired waist measurement (include 2” gap)

C. High hip, level with the bottom of the corset

D. Waist to top edge of corset at center front

E. Waist to bottom edge of corset at center front

F. Waist to top at princess (in line with apex of bust)

G. Waist to bottom at princess (in line with top of thigh)

H. Waist to top at side seam

I. Waist to bottom at side seam

(J.) Waist to low rib

(K.) Low rib circumference

(L.) Waist to top at center back

(M.) Waist to bottom at center back

(N.) Waist to top at back princess

(O.) Waist to bottom at back princess

For measurement G, you may wish to rest a thin hardcover book ,or something similar, on the subject's lap as they are seated to make sure the corset isn't too long. Note the placement of the ASIS (aka hip bones) for G and H; you don't want to have the corset stopping directly above the hip bones because the abrasion can be uncomfortable.

Measurements J and K are optional and will not be demonstrated in the drafting demo, but are valuable for clients with large or blocky ribs or more dramatic waist curves/tightlacing experience. In many, the bulk of compressible flesh is between the bottom of the ribs and the top of the hips, and thus that may be where you focus your waist reductions, rather than blending all the way to the top edge.

For purposes of this demo/in the name of simplicity, measurements L through O will be assumed to be consistent with their front equivalents. Once you are more comfortable with the patterning process, try varying these measurements to create different edge shapes, such as a longline, high back style, or an unusual custom silhouette.

Divide all circumference measurements by two as your draft will be symmetrical between left and right.

Sample Measurements

A. Underbust circumference: 27 (÷ 2 = 13.5)

B1. Natural waist: 24

B2. Desired waist: 20 (÷ 2 = 10)

C. High hip: 33 (÷ 2 = 16.5)

D. Waist to top at CF: 6

E. Waist to bottom at CF: 6

F. Waist to top at princess: 5.5

G. Waist to bottom at princess: 5

H. Waist to top at SS: 5

I. Waist to bottom SS: 5

(J.) Waist to low rib: 3

(K.) Low rib circumference: 26.5 (÷ 2 = 13.25)

Setting up the Draft

1. Cut a piece of pattern paper that's a little bit taller than the total length of your corset (D+E). For me, that means I need a piece about 14”. I like to make notes and calculations along the top or bottom margins. The width of the paper should be a couple inches longer than one half of your largest circumference measurement, which is most likely C, the high hip.

2. Mark the bottom edge, the waist line, and the top edge (all your circumference/horizontal markers). Start with the top or bottom so that you don't accidentally place the waist too high or too low and not have enough length to one side of it. Extend these into horizontal lines across the page.

3. Now, if the clean edge of your paper is not perpendicular to these guidelines, draft your own perpendicular line, then another line for your center front (busk) seam allowance. You probably want at least half an inch SA but this will vary with your construction methods. The line at the edge of the page is your cut line, the one half an inch in is your actual center front line.

4. On the waist, mark 1/4 and 1/2 of your C measurement, starting from the CF. If my CF line is 0, my other lines are at -.5” (for the seam allowance), 8.25”, and 16.5” for my measurements.

Drafting a Simple Underbust Corset

How much waist shaping and reduction comes from where depends vastly on the shape of the body it's going on. In general, most of the waist shaping is along the side to start with. Do you, or your client, have a natural shelf butt or swayback? You'll likely take more from the back and maintain a flatter front. As a rather bony person, I find it uncomfortable to have waist reduction taken from the back, as the muscle and bone structure isn't naturally squishy. Consider the client, even if it's yourself.

A lot of good corset patterning comes from just considering the anatomy. If you look at a skeleton or other anatomical model from straight on, the difference between ribs and hips is most apparent along the side edges. So it stands to reason that your side seam shape should reflect this. How I've handled it for this demo is to take my regular pattern drafting knowledge and apply it. The waist darts on a skirt, bodice, or torso block will probably be about an inch to an inch and a half wide. To keep my waist curve from starting out too extreme, I've decided to take an inch and a half of waist reduction and shaping from the front and another inch and a half from the back.

5. Divide your final waist measurement by four. 20 ÷ 4 = 5 (as per my scrawled notes on the top of the draft.) Add your dart intake, 1.5” to this. Mark this width, 6.5”, from your CF and CB lines. Don't worry about the back gap yet; it's easier to slice off the excess later in the draft than try to factor it into your initial calculations.

6. After that I'm going to mark the ends of my side seam, 5” up and down from the waistline. Square a line from the vertical side seam guide..

7. Mark the underbust width, 1/4 of measurement A. Now, if I mark the quartered underbust measurement as-is (6.75), it's only a quarter of an inch away from my waist curve, which is way too straight. Here I just used my instinct and added an extra half inch of intake to the top of the shaping, making my reference point 7.25. I place this point in line with the end of my side seam, 5” up.

8. Next I sketch in an approximation of my side seam shaping, from underbust to waist to hip spring. Once I like the way it looks, I true the lines with my hip curve ruler.

While the smoothness of the curves on your final piece depends a lot on a variety of factors, such as your boning, fabric, and interfacing, I find it helpful to blend each curve with an inverted curve. Again, I am considering the anatomy of the structure. The natural form of muscles and bones blends smoothly from one contour to the next, it's not a bulbous lump next to another lump as with a double-scoop of ice cream. Conversely, even the boniest figure is still composed of rounded forms without true angles. So along my waistline, I like to square up and down a little bit – after all, the waistline is a semi-fluid placement on the form, not a single placement with a fixed thickness of 1/32” or something. The hip and rib curves are obviously convex, meaning they curve outward, but the waistline curves inward, right? By blending the two, you get a smoother shape, fewer puckers, and an easier time at the sewing machine, than if you connect a straight line to an outward curve.

This is also what gives you your hip spring. How much of the curve/reduction is at the side seam and how quickly you accelerate the curve determines the proportion and shape of the hip spring on the wearer. This is one of those things that seems really obvious once it's been pointed out (or you've figured it out) but isn't necessarily self-explanatory off the bat. It's easy to just focus on the hip spring just being a function of the waist reduction.

The same theory applies to the shaping along your vertical seams, but first you have to know where to place them. Since there are 12 panels total in this basic design, that means each quarter of the corset has three panels.

9. Create the vertical guidelines for your other front panel seams. Divide your waist measurement (plus front shaping intake) by three to figure out about how wide each panel is.

6.5 ÷ 3 = 2.166666.... Well, that's an awkward number set, but 2 + 2.5 + 2 = 6.5 so that's a good starting point. Of that, we've still got an extra 1.5” of intake to get rid of. The middle panel will have intake removed from both sides, so that's why I've marked it wider than the other two.

10. Next you take out the dart intake along those vertical seam guidelines.
Again, there's more shaping as we approach the side, so I'm going to take 5/8” from between the first two panels and 7/8” from the second and third. This isn't a hard and fast formula, just intuition. You may want to change it based on the body in question and how your mockup fitting goes.

So I'll mark 5/16” from either side of the first line and 7/16” from either side of the second. Don't forget to square a bit up and down from your waistline guide to help you blend. Lightly draw a straight line down to the bottom of your vertical seam guide to help you plot your inverted curve blending.

When going up to the underbust level, don't forget that you may have added to that measurement to create a nice side seam shape. Since I added 1/2”, that means that each seam has 1/4” of extra at the top, so I'll mark 1/8” to either side and blend to there.

11. Now to create the back, I'll basically be doing the same thing, but first I have to transfer the side seam shape exactly. I fold the paper in half along my SS guide and trace the curve with a dashed line on the back side of my paper. When you open it up, if you've traced accurately, the pressure of marking the line has actually transferred some of the original pencil mark to the right side of your page. This makes your life that much easier. Grab your curved ruler and connect the dots.

12. This is a good time to shave off that back gap. Create a line 1” in from your CB guideline, then add your seam allowance back in. The back waist measurement plus intake for shaping will now be an inch smaller than that in the front; don't try to make the panels the same width.

13. Divide the back into three panels.

The measurement to my new CB line is 5.5”. 5.5 ÷ 3 = 1.83333... Another inconvenient bit of arithmetic. So let's make that 1.75 + 2 + 1.75.
When drafting small corsets like this one, try to make sure that the CB panel has enough room for all the boning and grommets and topstitching necessary. This is cutting it pretty fine once my shaping intake has been... taken out.

14. Remove your dart intake/shaping from the new back panels. I've followed the same pattern as from the front, taking 7/8” from the seam closer to the SS and 5/8” from the one closer to CB. The inverted curve blending at the bottom of these seams is even more important here, since it will be curving over the back of a pelvis and the roundness of the back hip/butt. Again I've got an extra 1/4” per seam released at the top. The back rib shape is probably flatter than the front rib shape.

15. Square a line from the top and bottom of your side seam curve.
To create top and bottom edges that will blend nicely without mucking about cutting and taping your pieces of paper, you can do a little bit of cheating. Square a line from the top and bottom of your SS shaping – it's not going to be in line with the grain, so if you square along the grain you'll have a pointed intersection. This will create the correct shallow angle.

16. Then draw a curve blending the new squared line to the top and bottom of your side seam.

17. True the top and bottom edges on your other seamlines. The line is disjointed where it crosses through your intake, but not to worry. You can square from the middle of the intersection, then true your curved edges to where the new squared line hits the seam line. On more complex or dramatic shapes this might not be sufficient (it'll be harder to eyeball a continuation of the curve) but it's enough to get you started.

Labeling Your Pattern

18. If you don't want to be endlessly confused, you need to label all your patterns as thoroughly as possible. The simple notation I've used on this pattern goes along the waistline. FRD1 18” is enough to tell me that it's piece number 1 of “FRD” (Foundations Revealed Demo) and the final corset size is 18”. If you prefer, you can label your pattern with “CF, F2, SF, SB, B2, CB” instead of numbering the pieces.

My full-blown pattern notation, demonstrated on one piece, follows this formula: “[pattern-number] [pattern-name] [piece name] [size]/[cut this many] [this fabric].” I like to assign my pattern numbers with the date in YYYYMMDD format. If I'm doing multiple patterns in a day it'll be date-1, date-2, date-3, etc. In this case the result is, “20120409-1 F.R. Demo Underbust Center Front (or Front 2, Side Front, Side Back, etc) 18”/1 pair strength 1 pair fashion.” “Cut 1 pair” is more technically correct than “cut 2” because the latter implies that you are cutting two of the same piece, rather than a mirrored set for left and right.

You might need to label both grainlines, one at the waist and one perpendicular.

Notching

19. You can also label your pattern pieces with notches, which is helpful for identifying cut fabric pieces rather than paper patterns. Obviously you're always going to want to notch the waistline. From there, I notch the seam between the first two pieces 1” below the waist. The next seam gets notched 2” below. Then we're at the SS, which gets notched 3” below. After that, we go in reverse, but to clarify that we're now at the back of the corset, I place two notches 1/2” apart (you could also do 1/4”). So between the side back and back 2 piece, I'll notch 2” and 2.5” down. Finally, between the back 2 and CB, you'll notch 1” and 1.5” below the waist.

Seam Allowance

20. The final step is to add seam allowance and cut out your pattern. There are two options for handling seam allowance. Some prefer to trace the pattern pieces without seam allowance and add it on the fabric. This may or may not make your pattern corrections easier. What I do is tape extra scraps of paper to the edge of my pattern and add the seam allowance onto them. Your center front and center back will already have SA from the draft and of course the top and bottom edges don't need it. Again, the width of your seam allowance will depend on your construction methods. I like an even 1/2”, some go as small as 1/4”, and if you're flat felling your seams you may want 3/4” or more.

21. Then would mock up the pattern and check the aesthetics of your style lines as well as the fit. Analyze the angle of the side seam in relationship to the front and back fit – does the front to back balance itself need to be shifted or just then angle of the SS? More shaping intake, a flatter front, a wider back?

You can also take quartered “arc” measurements for this draft: measure the front half of the body separate from the back half, rather than a full circumference measurement divided evenly into quarters. This is harder to do on yourself and it's difficult to maintain a consistent imaginary side seam as you move from the underbust to waist and hips (necessary for accurate measurements of the proportion between front and back), but you can measure over a well-fitted t-shift and use its side seam as a guide, if it lays straight.

Ta Da!

I hope you've enjoyed learning to draft this pattern on your own. While there are many fantastic historical patterns and patents, I always prefer the control of drafting my own patterns. Once you've got this basic pattern done, you can try manipulating it or using the basic techniques to draft other shapes.

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