Fisheye Dart = Changing Seamlines for Stretch Pants Fitting

I’m still playing with patterns and stretch fitting for pants- focusing specifically on the Clovers by Colette.  It started innocently enough, as an exercise to help me better answer Pants Blocks questions and as a way to sharpen my skills before teaching the Perfectly Fitting Pants workshop next month.

But now I’m kind of obsessed.  Every answer breeds another question.   I plan to keep chasing answers until I can’t find more questions.  Or until we get bored with pants.  Or until my 1934 German sewing magazine shows up.

Way back when I was fitting the Pinkie Pants, someone left a comment suggesting pinning out the extra fabric through the backside of the pants to allow the fabric to lie smoothly.  This is often referred to as a “fisheye dart” and it’s a perfectly reasonable way to adjust a pattern.  Check out this video detailing one way to do the alteration.

The problem with this is we can’t run around with darts on our backsides.  It just isn’t done.  I don’t really see why it’s ok to have all kinds of darts on the bust and not the backside, but we’ll leave that for now.  The fact is, if you’ve made a pair of pants that has extra fabric through the back, a fisheye dart is not going to help.

I documented the process I went through to whip my Clovers into shape and get rid of the extra back thigh fabric.  I removed excess fabric through the back inseam, and I deepened the crotch curve.  Still restless, I also shaved off the waistline seam and then took in the side seams.  It’s all fairly simple, once I worked out which way to go.

The interesting part came when I realized I did exactly what a fisheye dart would have done.  But with no dart.  Instead, I shifted the seamlines.  I’ll show you.

This is the finished pattern piece, with all my “notes” and new lines on it.  It’s a combination of my Pants Block and the Clover pattern, and also reflects the way I changed the seamlines during the fitting process.  For a medium bottom weight fabric with moderate stretch, this is my pants back pattern piece (though different fabrics will behave a little differently when cut from the same pattern!).  I didn’t change the front much; besides the fisheye dart doesn’t have anything to do with the front.  We’ll focus on the back pattern piece.

This is the pattern piece I started with.  It’s the Clover pattern combined with my block. I traced a second one for the sake of this exercise, but it’s exactly the same shape I used to cut out my Clovers last week.

This is the dart I pinned out.  After I sewed them together but before I did the Clovers fitting, I pinched out a dart to make the wrinkles go away on my pants.  I made note of it then and transferred it to this pattern piece for the sake of demonstration.

Then I pinned out the dart after cutting away the excess pattern paper.  This has no seam allowances.  Notice how the shape of the curve changes, as does the angle of the waistband seam.

Check out the darted pattern piece with the one I already know fits me laid on top.  The pattern piece on top has seam allowances, but the seamlines through the crotch and hip are identical.  Even the side seam.  The only difference is the shape of the dart, and I have to say using the larger dart that wasn’t cut off by my alterations makes sense.  Other than that detail, the crotch and waistband seams are identical on both pattern pieces.

The legs were different.  I scratched my head for a while and put it down to the fact that on one pattern piece I had folded out a dart, and on the other I hadn’t.  The “grainlines” are different, if you will.  I focused on only the inseam and side seams (because the crotch seam was sorted out by the dart) and carved away the same amount from the inseams and outseams on the darted pattern piece as I had on the Clovers.

They’re the same. (Sidenote- the altered pants pattern corresponds exactly to my full hip measurement.  It’s zero ease, but not negative ease.  Interesting.)  I took out that much fabric from the top of my inseam.  If I were cleverer, I would have taken out a little less there and a little more at the side seam to balance the seams.  As it is, I ended up with a pretty wearable pair of pants that fit reasonably well.  It’s interesting to note that pinning out the dart and shifting the seamlines yields much the same results.

The difference is that you can shift the seamlines on pants you’ve already sewn up, whereas the “fisheye dart” alteration can only be performed on the pattern piece, not a garment-in-progress.

I’d love to hear thoughts on this- you’re a sharp crowd…  Or questions- I’m not sure I explained this so well and I’d like to be quite clear.

Also– Thank you thank you so much for participating in the Waist to Hip Ratio survey (and for spreading the word!).  I have collected 289 sets of measurements since Sunday- wow!  It’s really interesting to play with the numbers, I look forward to writing a post about it this weekend.  In the meantime, if you haven’t already contributed, would you mind?  I’d really appreciate it.  The more numbers I have, the better my equations.

Also- What’s that on my drafting table?  Antidote Trousers?  Ooooh.  Those are my kind of pants… I’m trying two different ways of drafting wide legs/fitted hips to see which one I like best.  But that’s a project for next week…


  1. I’m not sure if my post disappeared or not! This method seems so clever! I am getting re-acquainted with sewing again, after a 20 year hiatus! (I fell in love with computers, and forsake my sewing machine. But now I have granddaughters who want clothes!)

    • Cool, Barbara! I don’t see any other comments of yours, so it must have gone somewhere… (To that big file 13 in the sky.. ;))

      Congrats on getting back into sewing! What kind of clothes do your granddaughters want? It’s cool that you sew for them.

  2. I do that all the time. It’s called a swayback alteration. Well-known to tailors and taught on most tailoring and dressmaking courses. But most bloggers do it wrong my making a vertical waist adjustment only. Go to Texas Agrilife Extension bookstore and look for Pattern alterations. As well as this one (E-382
    Pattern Alteration: Sway Back) you ill find many other treasures which will be useful to your teaching.

    • I am inclined to believe you, but I’ll mention that I have read about this and it was labelled “flat butt” alteration… And I looked in the mirror and thought “Well, I guess everything is relative.” Though I’d never classify my backside as flat.


      Makes sense. Also, thanks for the lead on the pattern alteration pamphlet. I love reading these! I can’t believe it’s free. Wonderful. Thank you, people of Texas.

  3. I wonder if the change in grainline you get with an on teh job adjustment is a good or indifferent thing compared to the control of making the adjustments before hand?
    Love the antidote trousers and all the other inspiration pants SO much more than skinnies!!!

    • Well- I scratched my head over that one for a while… Usually you want the pants grainline to be perpendicular to the floor, and it is on both of my pattern pieces there… The grainline at the top of the pants changes dramatically on the one where I pinned out a dart, but you’d just correct that and all would be well.

      So pleased you like them! I’m having a great time playing with the drafting. I think I may have committed this chapter in Pepin to heart- I’m working on the semi-circular pants draft, with the break line even with the crotch… It could be great or horrible, but that’s why I make muslins…

  4. I’m really enjoying reading about your pants fitting journey and when I have a little more time I will definitely be getting you to make me a block! I also don’t understand the ‘no dart on the bum’ thing. I recently read somewhere (can’t remember where) that to fit pants for women with a muscular thigh that creates a hollow at the top of the leg you should use a pattern with a seam down the front so you can remove the excess fabric. If you have a small waist and larger hips, you add extra waist darts to shape your pants. It would be so much easier to stick a dart in where you need it. In recent years there have been so many examples of bodices with darts in all sorts of places, so why shouldn’t pants be the same? Personally, I think the obsession with skinny pants that look like they are sprayed on is making us all (myself included) waste our sewing energy. I love tight clothes and I wear them all the time, but if I want that look I wear leggings (I know I said that last time, too). I really need to move back to Byron: I want to come to every class you hold from now until the end of time!

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