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How the knee width of trouser legs effects the width of the crotch


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#1 Schneidergott

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Posted 12 December 2013 - 03:30 AM

There appears to exist a common problem with the fit of trousers: They are either to wide or to tight at the crotch.

 

To get a solution you only need to know the following, which is merely a reproduction of an article in a very old (1920s) German cutting manual, which is no longer in my posession and now somewhere in the UK.

 

Have you ever wondered why jeans, that fit so closely at the legs yet are so comfortable at seat and crotch level? Or why those wide legged trousers feel so uncomfortable at the same area?

 

The reason is quite simple: The slimmer the legs, the more the crotch opens. This is a diagram I made (using very simple techniques) to demonstrate this (note that the front and rear crotch size stays the same).

 

This would represent a pair of trousers with a larger knee width. As you can see, the distance from A to B is relatively small compared to the version with a small knee width:

 

trousers2-1-1.jpg

 

 

This would represent a pair of trousers with a smaller knee width. As you can see, the distance from A to B is relatively wider compared to the version with a wider knee width:

 

trousers3-1-1.jpg

 

 

​What this basically means is that for the wider knee width you need a wider crotch diameter and vice versa to have the same comfort.


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#2 gramountoto

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Posted 12 December 2013 - 09:11 PM

Great post SG ! Very clear. Thanks.

 

Is this the way one should adapt a draft for a narrower knee ?

Should one modify the top trouser too ?

 

Spaltdurchmesser_zpsa7561e5f.jpg


Edited by gramountoto, 12 December 2013 - 09:12 PM.

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#3 Schneidergott

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Posted 12 December 2013 - 09:23 PM

It is one option, although I find it easier to make the back fork a bit smaller instead. Which is basically the same and much faster.


"Nur der ist Meister seiner Kunst, der immer sucht, das Gute zu verbessern und niemals glaubt, das Beste schon zu haben."
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#4 jcsprowls

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Posted 12 December 2013 - 11:01 PM

It is one option, although I find it easier to make the back fork a bit smaller instead. Which is basically the same and much faster.

 

Voila!

 

Fitting issues are - generally - typified by vertical and horizontal changes applied across an entire pattern piece. In effect, you slice into the pattern and overlap/expand segments to add more girth or length, always keeping the pattern balanced. The objective is to get the circumferences/girths aligned with the appropriate heights/lengths of the body.

 

Styling issues - with a few exceptions - are typified by dart-shaped adjustments. After the circumferences/girths are aligned, you sculpt the silhouette (i.e. the shape/edges of the pattern) to drape the cloth on the body. These are the third dimensional (i.e. "depth") adjustments that make each garment distinct like a snowflake.


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#5 Terri

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Posted 12 December 2013 - 11:24 PM

Great post SG ! Very clear. Thanks.

 

Is this the way one should adapt a draft for a narrower knee ?

Should one modify the top trouser too ?

 

Spaltdurchmesser_zpsa7561e5f.jpg

Yes, I understand your thoughts, but I think the change in the CB line should not move inwards as you have drawn but join back up to the original point, and the same thing with the outseam.


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#6 Terri

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Posted 12 December 2013 - 11:56 PM

SG, thanks, for the diagrams!

 

Here's my opinion- keep in mind I don't work in the fashion industry!

 

I think there is a problem in OTR clothing due to the fact that fashion changes are being made to a pattern incorrectly.

There is a huge interaction between the various elements of a trouser draft, the size at the thigh, the narrowness of the leg, the fork length and the shape of the crotch curve.

I think that what is happening is that the fashion changes are being applied (ultra narrow legs) without an understanding of how that change should be handled.

 

You cannot just narrow the legs of a draft without looking at what else it affects.  

 

If you took a nicely fitted wider thigh/leg  pair of suit trousers and arbitrarily narrowed the legs to the current fashion without changing the crotch curve and side seam run, you end up with a mess in the crotch.

The thigh size must be reduced and the crotch curve changed.

If the thigh size is reduced drastically, you still need enough overall crotch length to cover the body, so that has to be accomodated somehow- by either more bias in the back seam, or extra length added by slashing across and adding it in. If you slash the back across to regain crotch length, the side seam moves out.

That is why I made the comment above. I don't think it would be successful to change to the blue lines in the diagram.

 

If we look at the pattern changes that resulted here in tld9v1's post, I think we can see this happening. His previous trouser patterns and toiles  and more successful later pattern support the theory.


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#7 jcsprowls

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Posted 13 December 2013 - 04:43 AM

fashion changes are being applied (ultra narrow legs) without an understanding of how that change should be handled.

 

Yup. Within industry, we will make a copy of tried-and-true styles and then apply fashion/trend updates to them. It does require a thorough understanding of pattern architecture and anatomy, which is why I laid out the difference between fitting an style changes.

 

We still sew a specimen of the new/derivative garment for fitting and styling. The folly is skipping the sample stage without understanding the tradeoffs. Sometimes you skip the development sample and go right to the showroom sample; most times you don't. Wisdom comes with time and exposure.

 

Everyone makes mistakes. With RTW/OTR, your mistakes haunt you much longer than you'd ever want to admit. You tend to be much more methodical, rational and judicious when you see - first hand - how every change you make has a scalable impact to the company's operation or finances.

 

It's "butterfly effect" in garmento-land...


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#8 Schneidergott

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Posted 13 December 2013 - 08:07 AM

I mean, com'on, this is very old knowledge. Like I said, the original diagrams were published in a manual back in the late 20's or so. It was published by the owner of a cutting school in Frankfurt am Main. His name was Müller, too, but I don't know if he was related to Michael Müller in Bavaria.

And yet, I haven't seen this problem mentioned in any of the other manuals I have or in my magazines. Maybe it was handed down from master to apprentice/ student and got lost when the old masters died and the RTW industry took over completely?

 I took a pattern making class in the early 90's in Hamburg and when my (very knowledgeable) German-Russian teacher got fired because some of the other students (female of course) felt misjudged compared to me (several of the girls actually believed that I got better marks because I was the only guy in the class and not because they sucked hard at pattern making), she was replaced by another, much younger German-Russian teacher (the cutting school got them cheap because of government funding), who got fresh out of the Müller & Sohn cutting school and couldn't explain anything.

And, seeing the "skills" of my boss who trained at a design and tailoring school in Hamburg, it's safe to assume that things have gotten worse ever since.

 

The men's trousers pattern you can buy on the Müller & Sohn website has the shape and width of the trousers in the 90's, especially the rear trousers are extremely wide. So they are pretty useless if you want to derive a narrower style and expect them to fit well.

Still, I'm sure that is what many RTW/OTR companies did: They used their long running pattern from the early 90's and tried to change it to match a new, more fashionable silhouette.

I think that Müller & Sohn/ Rundschau should re-publish some of their old cutting manuals from the 70's. This a pattern for one of those skin tight versions:

 

ModerneHosen-0011.jpg

 

The calculation for the fork width (tight form on the left, the more moderate, but still close fitting version on the right). "Gw" means seat width or hip girth

 

ModerneHosen-0019a.jpg

 

ModerneHosen-0012-1.jpg

 

ModerneHosen-0013.jpg

 

ModerneHosen-0014-1.jpg

 

ModerneHosen-0015.jpg

 

ModerneHosen-0017.jpg

 

ModerneHosen-0016.jpg

 

 

 

 

 


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"Nur der ist Meister seiner Kunst, der immer sucht, das Gute zu verbessern und niemals glaubt, das Beste schon zu haben."
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http://www.dressedwell.net/ It's snarky, but fun.


#9 jcsprowls

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Posted 14 December 2013 - 12:55 AM

I haven't ever seen this in print, before. But, then... I've only become aware of Mueller and Sohn since meeting you and other German-trained tailors.

 

This is one of the many things I learned at the elbow of my grandmother (and, mentor). We referred to this as "stride" which is the width, depth and curvature that receives the torso. We measured at the same points in the Abb14 and Abb15 illustrations. We never codified a height measurement (viz. 8cm and 12cm, respectively). We took the measure at the point above the curve on the front and back panels.

 

Now that you've shared this info, I see your point of view. I concur. It was obviously codified. It's a shame it never made its way into English language references. I'm glad it was retained by tailors who brought it into the RTW sector, where it continued to be passed on for "generations".

 

It's interesting where the midline/fold divides the back panel in Abb14 and Abb15. It looks like the angle of the seat seam is 1/5 to 1/4 the back waistline. I feel like this proportion would fit much more smoothly than the 1/3 to 1/4 I was taught (and, mentioned in the other post where I explained how to balance a pattern).

 

 

________

 

So hey... in the formula for Abb14, what does the 'bis 2' mean? I'm reading the formula as: ((2 X [total-nude-hip-circ])/10) - 1.5cm __?__

 

Does 'bis 2' mean to subtract 1.5cm a second time? In French, 'bis' means 'again' as in: 1.5cm + 1.5cm = 3cm

  • If I take a 48" total nude hip, run it through the formula, it's yields a total stride width (converted to imperial) of 9", which seems right for a slim-fitting trouser.
  • If I subtract the 1.5cm (5/8") a second time, it gives me 8 3/8" which seems too slim compared to specimen patterns I'm looking at for reference.
  • If I add wearing ease (48" + 3" = 51") to the Gw value and run it through the formula, I get 9" which seems right, again.

Edited by jcsprowls, 14 December 2013 - 03:21 AM.

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#10 Der Zuschneider

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Posted 14 December 2013 - 05:58 AM

Too much secrecy here published now. I stay quiet. LOL


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#11 Schneidergott

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Posted 14 December 2013 - 05:59 AM

<p>Re.: Abb. 14<br />
<br />
&quot;von - bis&quot; in German means &quot;from - to&quot;, so the formula reads 2/10 seat width minus (from 1,5 cm to 2 cm). You could pick, 1,75 cm, but it's only a 0,5 cm difference. This means that the not skin tight fitting trousers have a stride that is between 2 to 3 cm wider.<br />
I usually choose a number that would give a plain total, and might even round up or down a bit. Since we cannot be 100% sure that the measurements we have taken are absolutely correct, there is no need to stick to millimeters of even fractions of them.<br />
<br />
After all, these are just basic formulas, a starting point, if you will. Some people have a bigger butt, others might be well equipped at the front.<br />
<br />
About the revieling of secrets:<br />
<br />
1. it's in German and uses terms you don't easily find in dictionaries.<br />
2. Most people may not even understand (and fully comprehend) it with a translation at hand.</p>

"Nur der ist Meister seiner Kunst, der immer sucht, das Gute zu verbessern und niemals glaubt, das Beste schon zu haben."
"Only he is a master of his art who always seeks to improve the good and never believes to have the best already"

http://www.dressedwell.net/ It's snarky, but fun.


#12 jcsprowls

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Posted 14 December 2013 - 07:51 AM

Thanks for clarifying. I get it, now. And, I think the formula works well for contemporary styles.

 

RE: rounding. I never mess with the formulas. I round the result to the nearest increment appropriate for the manufacturing tolerance of the style.

 

In other words: I would typically have a tolerance of +/- 1/2" in the hip circumference of the finished garment, so I would round to the fork length to the nearest 1/8". If the cutter's knife slips a little too wide and the stitcher stitches a slightly narrow seam, the finished garment will meet the tolerance/spec.


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#13 Henry Hall

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Posted 14 December 2013 - 11:04 AM

Those 70s Rundschau trousers (in the draft on page 15) look very much like the Rhinehart trouser draft.

 

I like the style of pockets on the first pair.


Edited by Henry Hall, 14 December 2013 - 11:07 AM.

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#14 Schneidergott

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Posted 14 December 2013 - 06:43 PM

Those 70s Rundschau trousers (in the draft on page 15) look very much like the Rhinehart trouser draft.

 

I like the style of pockets on the first pair.

 

When trousers are that close fitting, the regular pockets you will find on suit pants will gape. So the pockets need to be closer (higher up and also more in a horizontal position) to the waist band.

The dart in the front will provide a little bit of extra room/ fullness for the hip bone.

 

BTW: I find that any tight fitting style of "regular" trousers (not jeans or similar styles) benefit from a dart in the front. Even when there already is a front pleat.


"Nur der ist Meister seiner Kunst, der immer sucht, das Gute zu verbessern und niemals glaubt, das Beste schon zu haben."
"Only he is a master of his art who always seeks to improve the good and never believes to have the best already"

http://www.dressedwell.net/ It's snarky, but fun.


#15 gramountoto

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Posted 15 December 2013 - 04:04 AM

Thanks SG for this piece of wisdom.

 

DZ, I understand your point of view although I work in a field which has completely different views about sharing knowledge. But from what SG says this is old knowledge and this was know by all tailors back in the past : JCProwles learned it from his grandmother, so this is not even some "german secret".

 

This is how I see it : either nowaday tailors or designers have been trained by skillfull mentors and they know this all already, or they just learned it from this post and they acquired a knowledge which was basic maybe 30 years before. So this helps just saving some basic knowledge from oblivion.

 

But sadly those who don't know this probably either:

- don't know this forum (or even internet)

- don't speak english

- don't speak german

- have their own way to cut trousers and don't have time to think about new tips as they are already overhelmed by work

- won't read this thread

- Have been trained in such a way that they don't understand the interest of such what-they-might-consider-a-weired-math-formula (please see no contempt in this sentence)

 

This is all true for the only tailor I know, who is close to retirement... and one single of these conditions is sufficient.

 

But NOW I understand a bit more what you DZ wrote in response of one of my first posts about Rundschau trouser formula and Spaltdurchmesser... He he he :spiteful:

 

================

 

That said, I just don't understand why it's measured this way (left) since it doesn't take into account the angle of the inseam at crotch which depends on knee width (the original purpose of this thread). The final crotch in 3D is more like the right picture. Or does the number added or substract to 2/10 Gw reflect the shape of the trouser and the crotch ?

 

Spaltdurchmesser2_zpsbc971d95.jpg

 

=============

 



BTW: I find that any tight fitting style of "regular" trousers (not jeans or similar styles) benefit from a dart in the front. Even when there already is a front pleat.

 

This post from Jefferey Diduch shows how this dart might be located more outside.

 

http://tuttofattoama...ng-pockets.html


Edited by gramountoto, 15 December 2013 - 04:11 AM.


#16 Schneidergott

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Posted 15 December 2013 - 07:32 AM

The hip line is a basic construction line in all German drafts (and in most of the others I know).

I believe they use the method of aligning both hip lines (of front and back trouser) to have comparable results. Plus, if you rely on the knee width only, you won't be able to use and apply the formula correctly , because you may get different angles (and therefore distances) with every change of the knee width.


"Nur der ist Meister seiner Kunst, der immer sucht, das Gute zu verbessern und niemals glaubt, das Beste schon zu haben."
"Only he is a master of his art who always seeks to improve the good and never believes to have the best already"

http://www.dressedwell.net/ It's snarky, but fun.


#17 gramountoto

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Posted 15 December 2013 - 07:08 PM

The hip line is a basic construction line in all German drafts (and in most of the others I know).

I believe they use the method of aligning both hip lines (of front and back trouser) to have comparable results. Plus, if you rely on the knee width only, you won't be able to use and apply the formula correctly , because you may get different angles (and therefore distances) with every change of the knee width.

 

Thanks. Last question : this is with seam allowances (2x 0.75cm) I guess ?



#18 posaune

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Posted 15 December 2013 - 08:56 PM

Gramountoto. no allowance at crotch seam in back - but in front and inseams! (Wired!!)

The Spaltdurchmesser is measured like in the right pic.

With the slim form for pants you see here another form of construction from Rundschau.

It is built up from  2/10 Gw (hip).

lg

posaune

in woman drafting they measure from the angled hipline (depends on back crotch angle normal is 82°) in back crotch to the front hipline

and the spaltdurchmesser is (without s.a)1/4 hip-4 to 6 cm for pantstyle and you add or subtract for body form.






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