Women's bodice draft... +4 cm?

[Futura]

I'm going through each drafting method I come across in my library and am testing each one out. Some of the resulting drafts have been laughable, in part due to my own errors as well as those of the methods themselves! It's an excellent opportunity to learn nonetheless.

Right now I am attempting the basic bodice block from "Basic Pattern Cutting" by Maria Mori. Unlike the vast majority of books covering drafting intended for amateurs that I've seen, it uses proportions. I'm using my own measurements as the acid test. Accordingly, I'm following the directions for the heavily busted figure.

The directions state in order to draft for this figure type, one should use the chest measurement in place of the actual bust girth. From looking at the provided chart of measurements, they assume a standard/proportionate figure will have a 4 cm difference between bust and chest.

When drafting the back bodice for a large bust, they state to use the chest measurement plus 4 cm. Why 4 cm? My assumption is that this is so the proportions would be in line with that of a same-chested figure but with a proportionate bust. My reasoning for this is because for a proportionate figure they use the bust measurement throughout. For the back bodice on a proportionate figure, they would use 1/4 bust (for back A to B) without adding 4 cm.

Moving onto the front bodice, the instructions state to use 1/4 bust plus 4 cm for the width of the bodice for both a proportionate figure as well as a large busted one (front A to B). Why is this the case? Why would it be an addition of 4 cm here?

Nowhere in this book is there any mention of ease, so I assume the 4 cm isn't for that. I know that a bust circumference measurement does not provide any information as to the distribution of the girth... using 1/4 alone of the bust for the front bodice draft is inaccurate in my situation.

Any help or thoughts on this would be much appreciated! I am currently stumped. (Though that may be due to the heat. We've finally got summer weather!)

[Futura]

Here is a copy of the proportionate measurements from the same book:

[posaune]

This system is too old and limited. It depends on the bust cup how much you have 4, 6 or.... more centimeter. And the length from neck to waist must change accordingly. Think of a hill,  you have to climb it up and down. This is a longer way then walking on a plain straight across. And how more soil it needs to be covered  than a plain. Most proportional system can't provide a straight out of the box draft for big busted because they are not porportional anymore. There are some rules to follow so your pattern will be in balance.
If you use the bust circ mes. for calculating the back for big busted you will have a too big back and a too small front. It depends where and how she combines the bust circ with other measurements. The chest is supposed to be a "skeletton" measurement and the bust is thought of extra flesh added.  So only in front.
But for exercise it is good - you noticed already the flaws.
lg
posaune

[lepus]

Any help or thoughts on this would be much appreciated! I am currently stumped. (Though that may be due to the heat. We've finally got summer weather!)

What's the confusion? The 4 cm is the ease or tolerance (per body half) chosen by the designer for this block pattern, resulting in a total of 8 cm around the bust. That isn't an unusual value, both Natalie Bray and Shoben/Ward for instance use 10 cm in total for a basic block pattern.
Part of the 8 cm will be taken away in the centre back at E and in the shoulder dart at S, as well as disappear in the shaped side seam.

back E–F = back A–B = ¼ assumed bust = ¼ × (chest table value + 4 cm)
front R–F = front A–B = back A–B + 4 cm = ¼ assumed bust + 4 cm, or, for larger figures, = ¼ assumed bust + ½ × (real bust - assumed bust) + 4 cm
Totalling on this line: ½ assumed bust + extra for larger bust + 4 cm tolerance. Simples. Or not?

[Learner]

What's the confusion? The 4 cm is the ease or tolerance (per body half) chosen by the designer for this block pattern, resulting in a total of 8 cm around the bust. That isn't an unusual value, both Natalie Bray and Shoben/Ward for instance use 10 cm in total for a basic block pattern.
Part of the 8 cm will be taken away in the centre back at E and in the shoulder dart at S, as well as disappear in the shaped side seam.

back E–F = back A–B = ¼ assumed bust = ¼ × (chest table value + 4 cm)
front R–F = front A–B = back A–B + 4 cm = ¼ assumed bust + 4 cm, or, for larger figures, = ¼ assumed bust + ½ × (real bust - assumed bust) + 4 cm
Totalling on this line: ½ assumed bust + extra for larger bust + 4 cm tolerance. Simples. Or not?

Umm, not.  You're pretty much right with what you've said, but the part about "chosen by the designer" needs clarifying: Since this is supposed to be an ease free block, the 4cm, as you noted, is accounted for by the fact that the bust point is lower than the depth of scye line which uses the bust measure, and there are subtractions from this measure at centre back and side seams (and possibly at the back dart, since the location of the apex is unspecified).  The designer has "chosen" to round these subtractions to 4cm using some arcane method (it looks as if this 4cm is converted to 1⅓" in the instructions, and 1⅔" in the note; 4cm is closer to 1½", anyway).

Also, what you've said is correct:  the front should be ¼ assumed bust + ½ × (real bust - assumed bust) + 4 cm, but since the instructions are to use a quarter of the real bust measure, it will only be ¼ assumed bust + ¼ × (real bust - assumed bust) + 4 cm.

There's at least one error in the proportional measurements table, as well.

[Futura]

Many thanks for your replies. I am certainly finding it good practice to go through these different methods!

Lepus, thanks for writing it out clearly. And thanks Posaune for mentioning bust cup sizes. (I swear this heat is getting to my head! I was doing fine until the temperature skyrocketed.)

Learner, I am inclined to agree that it is intended as an ease-free block. None of the drafts throughout the book include ease, at least not explicitly.

Where in the instructions for a large bust adaptation does it list real bust - assumed bust? From my own reasoning I figured this was the case, but I don't see that written. My interpretation of the large bust directions is that Front A to B = 1/4 bust plus 4 cm and nothing else. What am I missing...?

Does the amount given as 4 cm added to 1/4 chest measurement vary with bust size? I don't see any mention of the difference between real bust and assumed bust, unless the 4 cm here is their sloppy interpretation of said difference based on their proportional table...

There's at least one error in the proportional measurements table, as well.

Arcane method is right! The proportional measurements table is sketchy at best. At first guess I imagine they converted from in to cm and only rounded to 2 figures, but halfway through the book it looks the other way round...! It is quite frankly a bizarre book. I have never seen these drafting methods used in any other book for amateurs. It even includes a section in the back covering the most basic of sewing methods, but fails to mention the fact that none of the drafts include any amount of wearing ease. Strange, but also interesting.

Yes, it would be easier to use a book without such mistakes, but I am learning so much from experimenting with each method I come across, even those books I disagree with.

Thanks so much to everyone for your assistance - it's very much appreciated! My apologies for being thick skulled due to the temperature.

[Futura]

From my own reasoning I figured this was the case, but I don't see that written.

Unless, the book actually doesn't say this due to an error on their part...?

[Futura]

After reviewing F.R. Morris's book "Ladies' Garment Cutting and Making" (the section for "Basis of Provision for Bust Development" at https://web.archive.org/web/20100110213522/http://vintagesewing.info/1940s/4x-lgcm/lgcm-03.html), I am under the impression the +4 cm in the back here is a fixed amount. It would be to create enough back width from the "raw measurement" of the chest to what is assumed proportionate and wearable.

It depends on the bust cup how much you have 4, 6 or.... more centimeter. And the length from neck to waist must change accordingly.

Posaune, I assume this amount depending on the bust cup only changes in the front. I see in this drafting method the front length is influenced by the width of the shoulder dart (A to R equals A to E of the back plus 1/3 of P to P1 of the front plus 0.8 cm, in which P to P1 is the dart width). What scale would have been used to determine the +4, 6 or more centimeters amount for the front bust cup allowance? The chart provided has the chest and bust difference for a proportionate figure at 4 cm. My guess is this is roughly equivalent to a B cup.

It seems there are many ways to interpret this amount of 4 cm! It is an excellent learning experience, and I am fully expecting to reach different conclusions and see things differently as I proceed further!

[Futura]

Hmmm.

I knew something wasn't right with what I was reading.

I double checked it only to discover from working with a small scale scanned copy, I'd missed an entire line of text and part of the illustration!

Frustrating? No doubt. Embarrassing? Perhaps...! Alas, my eyes need looking at.

Thanks everyone for putting up with that! A learning experience to say the least!

[Futura]

After revisiting my actual hard copy of the book, here is my understanding of the ease calculation for larger busts. Please feel free to correct, laugh at or delete as you see fit. It is my hope that this may aid anyone else who might stumble across the book in question ("Basic Pattern Cutting" by Maria Mori) and be curious enough to try it (despite its errors), but need a wordier explanation, although I make no assumptions as to the accuracy of the following...

For every 1 cm difference between the real full bust measurement and the proportionate-to-chest bust size (as calculated), add 0.25 cm to base 4 cm of ease for the front half bodice pattern.

Example (using arbitrary imaginary measurements simply to illustrate):

Real bust as measured = 112 cm
Chest = 98 cm
Bust as proportionate to chest according to chart provided = 98 + 4 cm = 102 cm

Amount in excess of 4 cm to add to front half pattern for large bust as follows:
(real bust as measured minus bust as proportionate to chest) x 0.25 cm = (112 - 102) x 0.25 cm = 2.5 cm

Amount of ease to add to front half bodice pattern = 4 cm + 2.5 cm = 6.5 cm

So, front half of pattern = 1/4 real bust as measured + 6.5 cm = (112/4) + 6.5 cm = 34.5 cm
Back half of pattern drafted for large bust = (bust as proportionate to chest)/4 = 102/4 = 25.5 cm

Half pattern total = 60 cm
Full bust width of pattern = 120 cm, which = real bust of 112 cm plus 8 cm of ease.

Alternatively, one can draw a line equal to (real full bust measurement + 8 cm) / 2, calculate the width of the back half pattern, and the length left over will correspond to the front bodice half pattern.

[posaune]

Thank you, now it makes sense. How are the armholes derived?
lg
posaune

[Futura]

Posaune, I'm glad that makes more sense.

For the proportionate figure, the arm scye is as follows:

The scye depth is calculated as (1/8 bust measurement or 1/4 basic proportion) plus (8 cm or 1/4 back nape to waist measurement, less 2 cm).

The back portion of the scye width is made up of the difference between 1/4 (chest + 4 cm) and 1/2 back width, as measured out from the center back line. Alternatively, in place of the measured 1/2 back width, the half back width may be calculated as 1 cm plus 1/8 basic proportion, plus 1/4 basic proportion. The back part of the scye is then drawn 1 cm out from the measured/calculated half back width mark, and shoulder point N extended out by about 1.3 cm.

The front portion of the scye width is equal to 1/8 of the basic proportion, plus 0.25 cm.

Point L1 is drawn 3 cm above L, where the scye touches. I have used Morris's guideline for drawing the scye with 1/6 of the basic proportion (drawn up from point L on the draft), which seems to hold true.

I'm having quite a bit of fun churning out drafts and studying where adjustments made alter the entire fit. I've also been coming up with more questions, naturally.

According to Maria Mori's book, for the front bodice, the extra length needed to cover the bust altitude is figured by taking the back scye depth, plus 0.8 cm plus 1/3 of the shoulder dart width P-P1. On my last draft using my own measurements, I calculated this amount (1/3 of P-P1) to be almost identical to that of Morris's method using 1/12 of the basic proportion. Is this amount really enough to accommodate a larger bust size?

I have tried to compare this draft against my own front nape-to-waist measurement, but it is off by quite a long stretch. Assuming that my posture is not to blame, this begs the question of whether the calculated addition to front length is not enough, or if the neck size is being drafted too small (or that my neck is disproportionate.) The back neck width is calculated as 1/8 of the basic proportion, plus 1 cm. (Morris's book gives either 1/4 of the neck circumference, less 1/2 inch (approx. 1.27 cm), or 1/6 of the basic proportion less 1/4 inch (approx. 0.64 cm).)

(I'm waiting on my husband to build my cutting table/work bench, so unfortunately I do not have the luxury of testing these out in full scale just yet! I have been working in 2D on SketchUp, which I suppose has saved a vast quantity of paper at least...!)

What would be the best way to take a balance measurement for the female figure? Surely it would be possible to have, purely as a reference point to check the posture of an individual, a method of comparing the back nape to waist length against the center front neck to waist measurement, thus avoiding the bust prominence entirely? Perhaps I am yet again missing something (!), but I cannot see how the nape-to-waist-over-bust measurement can accurately isolate and show posture discrepancies, considering the bust itself may be larger or smaller than average in addition to stooping or erect posture.

I would like to know what amount of front balance - for both the "skeleton's posture" and bust prominence - is deemed to be proportionate in relation to the back nape-to-waist measurement, and when to deviate from the proportionate draft and use the alternative disproportionate drafts listed in the book.

The book also doesn't show the amount to drop the front waistline shaping by. I have seen fixed measurements given as standard elsewhere, ranging from 1/2 inch to 3/4 inch. (Strange why I remember those amounts in inches, as I prefer to work in metric.) I presume this amount would have to be adjusted based on the figure type.

Perhaps the biggest pitfall of this book is the number of errors in the table of proportionate measurements. I can only assume they are errors, as there are several figures which don't seem to follow any kind of pattern. I created a table with the dimensions of drafts for each proportionate size given. I have tried to cross-check the front balance of the drafted patterns by calculating and comparing the given front nape-to-waist measurement, but it keeps coming up off. Would it be possible to swap these figures for a given set of proportionate measurements that is known to be correct? Or do different systems consider different shapes to be proportionate, thus making cross-referencing impossible...? More research is in order.

(Do forgive me if I'm asking silly questions and please excuse my ramblings! )

[posaune]

Ohoh
there are too many questions. What is the basic proportion?
For Ladies balance measurements it is more complicated as with men.
You have an upper balance and a lower one. For drafting you need both. And when you take the measures you have to deceide which belongs to which.
lower is simple: (waist to floor) CB and CF must be the same and the side seam will be more depending on the hip curve so bigger than CF and CB.
Not so the upper. As you wrote it depends on the bust size (and posture). You can say it must be as long as the back + X. If you are very rounded in the back the X will be small - if you are a Cup F it will be big.
And it depends on the place of the waist line, for theory assume the lower balance is okay and the waistband is horizontal.
In my drafting system the waist line will not drop, all what with X is added goes up.
example: For a bust about 90 -99 it is Backlength + 4. For a bust circ from 110 -119  it is backlength +(1 to 1.9) + 5
Other systems go down. You see this a wide field.
Because as you said different systems have different proportions. So my numbers are of  no use for you. A proportional system helps you making drafting easier. You can compare the measurements to your taken ones and see where they differ.
But don't forget  if you have an old system - remember the modern human being is not built like they were in older days. In my opinion it is interesting to see and you learn a lot,  but....................

lg
posaune

[Futura]

Oh dear! You are right, I forgot to include the basic proportion...! I must have missed that when I cut and pasted the text into the forum from drafting it in my email account.

The basic proportion according to this book is: 1/3 bust + 1/2 back nape to waist measurement, less 5 cm or 1/3 bust + 15 cm (= 6 inches).

The scale 1/3 bust + 15 cm is the same as used by Morris for sizes larger than a 36 inch bust.

Ah, a upper balance and a lower one? Most fascinating!!! I will study your post further after I have had lunch... Many thanks for your reply. Sorry for thinking of so many questions

[Futura]

Okay, after many months dealing with house renovations and a nocturnal 1 year old, I think I understand the concept of upper and lower balance. Maybe if I'm lucky I will have some time to study!

I am wondering if it would be worth purchasing the Muller & Sohn textbooks. The only reservation I have is that I would prefer to have an older edition, as I don't like the thought of contemporary lines influencing my drafts...! I understand that the average human shape may have changed over the decades, but I enjoy studying the drafts as they were intended throughout different eras.