How to Draft an Underbust Corset from Scale

Adjusting your Pattern

The first thing you will want to do before drawing your corset full size or altering your full size pattern is create a measurement chart for yourself.   This will save you from needing to re-do calculations.   Just plug them into your calculator and write them down, rounding to the nearest 1/4”.   The bust is not included because it is not needed for an underbust corset.

The only tricky part of the chart is figuring out where to put the Corset Waist (CW).  Generally, you will want to favor the Natural Waist (NW) unless the Smallest Waist (SW) is a significantly different measurement and closer to the Underbust than both the bottom of the Rib cage and the Natural Waist.  The circumference measurement of the Corset Waist is the reduced waist measurement to use for the corset pattern.

Underbust Corset Measurement Chart - Blank - How to Draft an Underbust Corset From Scale, by Sidney Eileen

For our example, we’ll follow the adjustments of Ester, a fictitious steampunk.

Ester’s measurement chart is as follows:

Underbust Corset Measurement Chart - Example - How to Draft an Underbust Corset From Scale, by Sidney Eileen

Ester’s Natural Waist (NW) is very close to her lowest rib, but her Smallest Waist (SW) is an inch higher.  To balance the two, she is placing her Corset Waist (CW) at 3.75” from the Underbust.

A 10% reduction of her Smallest Waist is 32.5” – 3.25” = 29.25”

A 10% reduction of her Natural Waist is 34” – 3.4” = 30.6”

She decids to split the difference and make the Corset Waist measurement 30”.

 

If you are starting from a scale pattern, draw the pattern lightly on large paper, full-size.  Be sure to leave a few inches between each piece for pattern adjustment and seam allowance.

On the left-hand side of the paper, mark vertically the distances between your Underbust, Rib, Corset Waist, Point Of Hip, and Hip.

Ester’s measurements are closest to the “Curvy” sample pattern, so she starts from there.

How to Draft an Underbust Corset From Scale, by Sidney Eileen

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Move the waist of the pattern so it is level with your corset waist mark.  Move the underbust of the pattern so it is level with the underbust mark.  Move the hip of the pattern so it is level with the hip mark.  It can also be helpful to create a rectangle “piece” on the very right 1”-1.5” wide, to represent your lacing gap.  If you forget to leave out the lacing gap at one height and not another, the final corset won’t fit.

Ester moves the critical parts of the pattern so they match her personal vertical measurements.

How to Draft an Underbust Corset From Scale, by Sidney Eileen

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Add together the widths of all pieces at the corset waist, including the lacing gap.  Compare this number to your ½ column Corset Waist measurement.  If your ½ Corset Waist measurement is larger, you will need to add in the difference.  If your ½ Corset Waist measurement is smaller, you will need to remove he difference.

Add width in 1/4” increments, starting from the back panel and working toward the front.

Remove width is 1/4” increments, starting from the front panel and working toward the back.

Including the lacing gap, Ester’s ½ Corset Waist is 15”, but the sample pattern ½ Corset Waist is 14”.  This means she needs to add 1” to the waist of her pattern.  She adds 1/8” each to the right sides of Panels 6 and 5, and 1/8” to both sides of Panels 4, 3, and 2.  Since Panel 1 is still wider than any of the other pieces, she does not add anything to it.  She also widens each piece so they keep their shapes.

How to Draft an Underbust Corset From Scale, by Sidney Eileen

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Add together the widths of all pieces at the underbust, including the lacing gap.  Don’t forget to include the lacing gap.  Compare this number to your ½ column Underbust measurement.  If your ½ Underbust measurement is larger, you will need to add in the difference.  If your ½ Underbust measurement is smaller, you will need to remove the difference.  Add or remove predominantly in the center (what will be the side of the corset) and the back.  Try to keep the shape as similar to the base pattern as possible by spreading the addition or removal of space evenly across all pieces which have curve to them.

Ester’s ½ Underbust is 16”, and her pattern ½ Underbust is 17”.  This means she needs to remove 1/2” from top of her pattern.  She decides to remove 1/8” from the right sides of Panels 6 and 5, and 1/8” from the left and right sides of Panels 4, 3, and 2.

How to Draft an Underbust Corset From Scale, by Sidney Eileen

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Add together the widths of all pieces at the hip, including the lacing gap.  Compare this number to your ½ column Hip measurement.  If your ½ Hip measurement is larger, you will need to add in the difference.  If your ½ Hip measurement is smaller, you will need to remove the difference.  Add or remove predominantly in the center (what will be the side of the corset) and the back.  Try to keep the shape as similar to the base pattern as possible by spreading the addition or removal of space evenly across all pieces which have curve to them.

Ester’s ½ Hip is 22.5”, and her pattern ½ Hip is 20”.  This means she needs to add 2.5” to the bottom of her pattern.  She decides to add ½” to the right side of Panel 4, both sides of Panel 3, and the left side of Panel 2.  She also adds ¼” to the right side of Panel 2 and the left side of Panel 1.

How to Draft an Underbust Corset From Scale, by Sidney Eileen

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Now draw smooth curves between your underbust, waist, and hip marks on all the pieces.  Use the shape of the sample patterns as a guide, and modify if desired.  Have at least 1/2” of vertical space at the waist, even for the men’s pattern, so the waist won’t cut in.  The straighter the line between the underbust and the waist, the more “V” shaped the final corset will be.  At the other end of the spectrum if the curve is too exaggerated you will end up with a pinched or “wasp” look at the waist.   While this is not usually desirable on the top of a corset (and can be uncomfortable as well), it is often desirable at the hip to provide a dramatic spring.  If you don’t want a dramatic spring, make the curve from waist to hip less pronounced.

Double-check the pattern, adding up the widths of all pieces and verifying that they add up to your target numbers.  If they don’t, adjust the shape.

An optional guideline is to add up the widths of the pieces at the Point Of Hip height.  The pattern measurement should be less than your ½ Point of Hip measurement, but not by as much as your waist reduction.  Plus-sized individuals will be fine anywhere in that range.  However, the thinner you are, and thus the less soft flesh there is to squish, the more important it is that your ½ Point of Hip measurement is close to the pattern measurement.  Compressing too much can cause pinching and discomfort against the immovable bone.

Ester checked all her measurements against the pattern and found they matched up. She also checked the Point of Hip and decided the pattern was fine as-is.

Strongly mark the waist point on each piece.

The next step is to define the top and bottom edges of the corset.  You can have it cut straight across at the underbust, point up in the center front, gently curve up in the front, stop an inch or two below the underbust, or even take creative ups and downs.  For the hip it can point down in the center, climb dramatically up at the hip, or take some other entirely irregular shape.  It’s up to you.  Lightly draw a line where you want your edges to be.

Now make sure the lengths of your seams will match up.  Take your flexible ruler or your string and measure from the waist point to the edge of the corset.  Mark the edge of the corset.  On the mate seam, measure the same length and make a mark.  Do this to every single seam.

Draw the lines defining your top and bottom edges.

Add your seam allowance to the left and right sides of each piece.  Use whatever seam allowance you are comfortable with.  Most commercial patterns use a 5/8” seam.  I usually use a 1/2” seam.  Whatever you choose, be consistent.

Make all other pattern marks.

Put a triangle at the top of each panel.  It’s very easy to invert panels when cutting or sewing, so transfer this mark to the wrong side of your fabric when you cut out the pieces.

I do not use traditional tabs to mark matching seams because it is too easy to loose the waist line.  Instead, in the seam allowance of each panel, I mark the waist point on the seam with a solid circle, and indicate matching seams with increasing numbers of small circles.  The left side of Panel 1 should be marked with one “O”.  The right side of Panel 2 should also be marked with one “O” to show that it is the mate for the seam.  The left side of Panel 2 should be marked with “OO”, as should the right side of Panel 3, and so on.  When you cut out your fabric, be sure to transfer these marks along with the waist point.

If you are planning to use a metal busk, add seam allowance to the center side of the front panel.  Otherwise, mark the center side to place on the fold.

If you are using single-core construction, add 2.5” to the outside of the back panel (Panel 1), but keep the edge mark for the corset.  This will give you room to fold over the core and cover material so you have a stable, smooth grommet area.

If you are using dual-core construction, mark the back edge of Panel 1 to place on the fold.

Mark your pattern with the grain line.  Unless you are already familiar with fabric grain, bias, and how these things interact when sewing garments, place your grain line perpendicular to the waist.  Generally in corset making the ideal grain line is vertical to the body.  In vertical-panel patterns like the types described here, vertical to the body is usually perpendicular to the waist, but not always.  For simplicity just place your grain line up and down relative to the waist line, and adjust from your mock-up when you can see exactly how it falls on your body.

Ester decided to use a smooth line for the top of the corset, and a bit of a lift at the side of the hip.  She made sure all her seams were matching lengths, created all her pattern marks, and added a seam allowance of 1/2”.  She’s not sure if she wants to use a busk or not, so she marks Panel 6 so it can be used with or without a busk.  She also plans to use single-core construction, so she adds the extra allowance on Panel 1 and leaves the mark for the edge of the corset clearly visible.

How to Draft an Underbust Corset From Scale, by Sidney Eileen

Finished sample pattern

 

 

 

Additional Thoughts

When you create a garment pattern, you are creating 2-dimensional pieces which, when put together, will create a 3-dimensional shape.  It helps if you visualize how the 2-D pieces will fit onto the final 3-D form.  The visualization will likely never be perfect, but with practice visualization will make it easier to decide where to add and remove width from the pattern pieces.

The human torso, even when circumference measurements are very close, is not a cylinder.  The smaller a person is, the more likely it is that he or she is thinner viewed from the side than from the front or back.  Shaping curves are predominantly along the side of the torso, and it’s important to include a curve in the back to accommodate the natural curvature of the spine.  Excepting those individuals with very, very low body fat percentages, the abdomen of a mature human (male or female) comes down from the rib cage further forward than the pelvis and then curves gently in at the level of the pelvis.  Cinching the waist in the front can cause discomfort to the abdomen, so it’s usually best to leave it straight or curve it gently in below the waist so it hugs the curve of the lower abdomen.

The sample patterns are based on an average number of panels, with the waist measurement fairly evenly distributed among the pieces.  Since the waist width on each pieces is similar, the shape of the torso is reflected in the different amounts of curve in each panel piece.  On slight figures, the number of panels can be reduced.  The center front two pieces in particular can often be made as a single piece.  The center back panel is usually just a little wider so it has room for boning and grommets, being no smaller than 1.5” at the waist.  On particularly curvy figures, dramatically widened pieces can create a great deal of bias stretch, resulting in a corset that has a greater finished circumference than the sum of the widths of the pieces.  While this might be desirable in some instances, it can require multiple mock-ups to get the perfect fit and a smooth shape.  Alternately, you can add another panel when there are multiple curves more than an inch out from the waist.  The only limit to adding panels is waist width, which can be as small as 3/4” on a single panel.  Smaller than that and you’ll likely experience technical problems when assembling the corset.

When you look at a beach ball, it is technically round, but often you will see a peak at each seam.  This is because each “panel” of the beach ball is exactly the same shape, so when the seams meet they bump against each other rather than flowing into one another.  To create a smooth shape on a corset, you do not want the curves that meet along a seam to have exactly the same shape.  Thus, if more than 1/2” of width is being added at a seam (sum of both sides of the seam) it should be added unevenly.  For example, if you are adding 3/4” at a seam, you will want one side to extend 1/4” out from the waist, and the other side to extend out 1/2”.  If you are adding 1” at a seam, you will want to split the addition at 3/4” and 1/4”, or just more than 1/2” and just less than 1/2”, depending upon which seam you are looking at.  In the sample patterns this asymmetry to the seams can be most easily seen in the hip curves. Until you are familiar with how the shapes of the panels affect the final shape of the corset, use the sample patterns as a reference for where to place greater or lesser widths.

 

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