slopermain image How To Draft A Back Bodice Sloper: Update

I cannot express the importance of a sloper. A sloper, or a block, is a basic pattern (bodice, sleeve, skirt, pant, or dress) that is made to fit a particular individual, size, or mannequin exactly and perfectly. It’s like a second skin with just a tad of wiggle room. It has minimal darts and is usually sewn with muslin or some other light-weight cotton fabric. From this pattern, other patterns can be drafted by manipulating the pattern (unless the design requires draping, in which case the pattern is made by draping and then trueing). A sloper is also a tool to use throughout the design process because when patterns are manipulated, shapes can become distorted and it’s a good habit to compare the shapes of the manipulated pattern to the shapes of the sloper pattern so that the original pattern shapes are maintained as much as possible. Throughout the design process, I’m constantly going back to see that the armhole depth/length/shape is as close to my sloper as I can get it. A sloper is also a tool to use when dealing with commercial patterns – you can compare specs and pattern shapes and adjust the commercial pattern as needed so that it is as close to your sloper as possible.

My method differs from a textbook’s sloper drafting method in the amount of ease that is built into the pattern. If a sloper is supposed to be the closest approximation of your body in fabric form, why add 2” of ease (this is what every textbook I have read suggests)? A sloper should be form fitting but also moveable and the amount of ease I build into the sloper pattern gives just enough wiggle room to allow easy movement while still being fitted.

Assuming that you used my tutorial on how to draft a front bodice sloper, then you’re ready to draft the back. Let’s get started.

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First, we must measure and record a couple of measurements. Just like I cannot express the importance of a sloper, I cannot express the importance of accurate measuring. Ninety-nine percent of the time, reader’s questions are answered by correcting their measurements. It’s not the drafting method that is incorrect – it is their measurements.

The first steps to measuring are determining who will take the measurements and time. I highly recommend that someone measures you but measuring solo is not impossible. If measuring solo, be sure to stand in front of a full length mirror while measuring and be sure that the measuring tape is level while measuring. I also recommend setting an hour aside to take all of your measurements. Spend one hour to get accurate measurements or spend six hours remeasuring yourself and redrafting your sloper because accurate measuring was not done on the first go.

The second step to measuring is wearing the correct clothing. Wearing only undergarments will yield the most accurate measurements but if someone will be taking your measurements, it is okay to wear workout/exercise clothes such as leggings and a tight tank top. Also, make sure that you wear the same bra while measuring and throughout the sloper fitting process.

Whether you wear undergarments or exercise clothes while measuring, I also recommend that you mark your CB line, shoulder line, shoulder tip, neckline, armhole depth, side seam, and waist line with a marker, pen, chalk, or pins. You can eyeball all of these measurements except for shoulder tip, armhole depth, and waist line, which I will show you how to find below. This will keep measuring points consistent throughout the measuring process.

Stance and breath is also important while measuring. Be sure to stand upright, on a flat surface, with feet slightly apart, and with weight distributed evenly. Also, breath normally while measuring as any large inhales or exhales can distort measurements.

Before taking any measurements, a waistline must be defined. To find the waist line, tie a string, shoelace, or tie around your waist – don’t tie it too tight or too loose; tie it just right – and wiggle around to let the string fall to your natural waist.

Now we can measure! Measure and record the following measurements anduse the diagram where applicable (for very simple measurements, I did not include a diagram).

{CB LINE} line perpendicular to prominent bone at nape of neck (TOP of back neck)

{FULL LENGTH} shoulder at neck to waist line

{CB (CENTER BACK) LENGTH} prominent bone at nape of neck to waist line

{SHOULDER TIP} ¼” from the end of shoulder (if you start to raise your arm, a hollow will form at the shoulder joint. This is shoulder tip – approximately)

{SHOULDER LENGTH}  shoulder at neck to shoulder tip

{ACROSS SHOULDER} shoulder tip to shoulder tip – MEASURED on back – and DIVIDED by 2 (across shoulders for both front and back bodice sloper is taken on back)

{SHOULDER SLOPE} CB waist line to shoulder tip. Be sure to keep measuring tape taut and to extend it straight from waist to shoulder tip

{SIDE SEAM LENGTH} armhole depth to waist line

{BACK NECK} tie a chain/tie/elastic loosely around the neck and allow it to rest at the neck base. Then measure from CB neck (prominent bone at the nape of the neck) to shoulder seam along curve

{BACK ARC} CB to side seam/AH (ensure that measuring tape in level and perpendicular to armhole base/CB line)

{ACROSS BACK} CB line to armhole at approximately 5” DOWN from shoulder seam/neckline (remember to mark armhole line with marker, pen, pins, etc). A way to cross check this measurement is to subtract ½” from across shoulders. Example: If your across shoulders is 14,” is your across back in the range of 13 ¼ – 13 ½”? Across back and across shoulders have a standard relationship that ensures the armhole is a smooth curve from shoulder seam to the base of the armhole on both front and back. I posted about this relationship here.

{WAIST ARC} CB line to side seam along waist line
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A-B: Full length

A-C: Across shoulders, squared from A

Square a line down 7” from C. This will be a guideline for drawing armhole

B-D: Center back length

Square a line out 4” from D. This will be a guideline for drawing neckline

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B-E: Square a line out from B equal to waist arc plus 1 ½” (for dart)

B-G: dart placement, measured out from B

G-H: 1 ½”

G-I: ½” G-H

B-J: Side seam length (on B-D line)

J-K: Square a line out from J equal to back arc plus 1/8” for ease. It may not seem like a lot but 1/8” on front and back pattern will be ½” in the round.

J-L: B-I

L-M: ¾” squared down from L. This will become dart point

Draw dart legs by connecting point M with points G and H and extending line down 1/8” at each point. After, draw a curved line from point G to B and point H to E using a curved ruler. Ensure that waist line intersects side seam and CB at a 90 degree angle.

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B-N: Shoulder slope with N falling on C guideline

A-O: Back Neck

Draw a line from N to O. If this measurement does not equal shoulder length plus ½” for dart, it is okay to extend or shorten the line accordingly. Be sure to extend/shorten the line near the C guideline (do not extend or shorten the line at the neck). You do not want to change back neck width because just as with across shoulders and across back, front and back neck width have a ‘standard’ relationship which I’ve posted about here.

Square a line down from O to D guideline and label P. O-P line should be perpendicular to O-N line

P-Q: ½” diagonal line (45 degrees) from P

Using a curved ruler, draw neckline with line touching points D, Q, and O. It is okay if line does not follow O-P line exactly near the intersection of the shoulder seam at neck. Back neckline connects with front neckline and it’s more important that the neckline is a smooth curve from CB to CF or vice versa. But it is important that necklines intersects CB at a 90 degree angle.

O-R: ½ O-N

With a ruler touching points R and M, draw a line 3” down from R and label S. This will be shoulder dart point

Mark T by measuring ¼” out from R (on O-N line towards neck) and square up 1/8”

Connect T with points O and S

Mark U by measuring ¼” out from R (on O-N line towards AH) and square up ¼”

Making sure T-S and U-S are of equal lengths (adjust as needed) and connect U with points S and N

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Draw a line from K to E

K-V: ½” down from K on K-E line (this will become bottom of armhole)

D-W: ½ of D-J plus ¾”

W-X: Across back plus 3/16” for ease (plenty of room to raise arm up and in front of you)

Using a curved ruler, draw armhole. First, draw the top of the armhole with curved ruler touching points N and X and then draw the bottom of the armhole with curved ruler touching points V and X. After, eyeball and true the shape. The armhole should curve slightly inward from shoulder seam to mid-armhole and then scoop to meet the side seam. The armhole should intersect side seam at a 90 degree angle. This will ensure that back armhole transitions well to front armhole and that the base of the armhole is flat. But it is okay if armhole does not intersect shoulder seam at a 90 degree angle. Just like neckline, back armhole will connect with front armhole at the shoulder seam and it is important that it transitions well. 

Lastly, true the shoulder seam by folding the dart closed (making sure dart intake is pressed towards CB) and redrawing shoulder seam so that it is a smooth line from neck to shoulder tip.

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