comparing curves

The mysteries of the crotch curve. After all these years, I still don’t have a firm understanding of this critical concept. I’ve been in another round of pants fitting (lost significant weight and it was time) and had an aha! moment about what I need in a curve and how it should be placed. Coupled with that, there’s been an interesting discussion going on at Stitcher’s Guild regarding this shape. These things motivated me to do a little tracing and comparing.

This would have been a better example if I had basic trouser patterns in all the pattern companies represented, but my Knipmode sources are limited to two magazines. Knip was critical because that is the curve that I really wanted to compare. So I selected the knip style that I had and then went on to find similar styles in the other companies – as close as I could.

Sizes – I used a 42 inch hip measurement – very close to the 106 cm measurement used by Knipmode and Burda. This meant that McCall and Vogue were size 18, Burda was a 44, and Knipmode was a 42.

Deciding how to align them for the overlay was a puzzle. I decided to align them based on the deepest part of the curve, with the grainlines parallel. For Knip and Burda, I positioned them so that the points were vertically aligned. I did the same for Vogue and McCall, too, but then backed them away a bit because they are designed to come together at the center of the body. The European cuts come together more towards the front. Maybe there is a better way to align for comparison?

So here is the picture. My lines are a little wobbly, but it’s easy to see that there is a clear difference in the four curves.

back curves



McCall and burda have almost the same angle of slant, but the McCall is much more L shaped.

Knipmode is the only one that has an actual hook. The lowest point of the curve is not at the point.

That Vogue curve is very shallow. When I look at it, I know why people need to scoop to alter some patterns.

Burda has a curve that I can imagine conforming to my contours. But look how the Burda seems to allow for a thicker waist than Knipmode.

There is more to fitting than crotch curves, of course, and that’s one of the reasons it is such a challenge for someone like me to understand. Side seams and the angle of the waistline relative to the center back and sides are also parts of the equation.

But what I understand from comparing these curves is that, depending on a person’s own anatomy, one of them would be a better starting point than the others. And you wouldn’t be able to just make the same kind of alteration across the board to get them to fit. One might need a scoop, another might need a wedge either added or taken out, and so on. In the most recent pair of pants I fitted (Burda), I tried tweaking in all the usual ways to get a better fit with no luck. Finally, I put them on inside out and pinned the center back to conform to my body. Turned out the curve needed to start higher.

I’d like to develop TNTs for a few more pant styles, so there are more muslins in the future. Here’s an exercise to add to your yoga practice…starting in mountain pose, twist to one side until you can pin the center back seam of your pants. This pose is called “the seamstress”.


33 thoughts on “comparing curves

  1. That’s interesting. I have never made a McCalls pants and had no idea that the crotch shape was so different from Vogue. I have a flat rear end, long and low and an L shaped back crotch is what works the best for me. As well as a short front crotch curve. I have successfully fit Hot Patterns which has a real L shaped back crotch and more recently I fit the Eureka pants pattern successfully. It comes with 3 back crotch shapes for average, flat and full rear end.
    When I was younger and thinner I successfully made Burda pants. These days I’d really have to lower and scoop it.
    Because I have a hard time fitting pants I prefer to have a tnt pattern and make changes in leg width and details. It takes a bit of time and effort, but it’s worth it especially if you are like me and wear mostly pants.
    Good luck with your journey.

  2. Very interesting. Thank you for doing this. One of the reasons I have just started sewing again after 25 years is to get pants that fit properly. I get the feeing it is not going to be easy.

    • I have to be in the right frame of mind, and allow myself plenty of time. Fitting pants is nothing that should be approached with a deadline looming! Good luck to you – it is so worth it to be able to make well fitting pants.

  3. Great visual aid there…we all need to know the differences between the brands! But…here is also the issue…the center back seam runs down your sacrum, the flat part of your pelvis and then runs forward to va-jay-jay junction which varies also on most women. If you like your pants tight like jeans then the back curve will be longer and the front curve shorter. Let’s say your total crotch length is 30…the back is normally 18 and the front is 12 but these 2 numbers can vary a lot depending on the design of the pant/jeans/leggings. I have seen pants in the cheaper See N’ Sew patterns with the front and back measurements almost the same without any thought to the va-jay-jay- junction and the inseams that cross it. You have to ask yourself…where DO I want my inseams? They can vary as well…way forward on jeans and way back on loose trousers…it’s a turkey shoot! Then once you get all this set in your brain and on paper…what about your cheeks? Have they dropped? If so, you need to drop that crotch curve to accommodate them too or your back seam will go merrily along thus emphasizing each cheek as you pull the wedgie out of the crack. But once you get everything correct…angels sing!

    • Interesting figures for difference front to back. My crotch length is 32. Using SFD, where I started trying to draft a pair of pants, front ended up 14 and back 18. Just 4 of a difference, calculated to be that way. I need more like you say and think that’s 12 at front and 20 at back, measured. I’m tall, this isn’t all booty (though a lot of it is) but I do have a sloping waist. My tutor suggests in skirts etc to split the difference a bit, so accept front a little higher than I want and back a little lower to visually improve. I’m also aware that the pants I own have the crotch point towards the front, as per European cuts, so that has an impact.

    • That’s why I started sewing Mrs. Mole–I inherited a booty problem from both grandmothers (lol). They only wore dresses. When I finally got it right, inseams, crotch, straight side seams, it was a momentous occasion. I hang on to my (cardboard) sloper like it’s gold.

  4. What an interesting post. I am always tweaking this measurement. As my body gets older (the mind remains intact thankfully) I have noticed several changes are required with fitting. I use many Vogue patterns and need to fuss a bit, I am going to pick up a McCalls pattern tomorrow and see just how that L curve works for me.You have given me another project…..thank you.

    • Like someone else has commented, the curve can differ even with the same pattern company depending on the style. I hope you can look at the instruction sheets where they show the pattern outlines and find one with a nice L.

  5. Interesting! probably the most ‘feared’ alteration for we garment sewers! Can you share the Artisan Square discussion title? I’d like to follow that thread. Thanks.

    • It is currently in the Spring 6-pak thread, but I think the moderators are going to move the pertinent posts to a pants-fitting thread.

  6. Thought-provoking post. Thanks so much. Like Ann, I’d like to follow the Artisan’s Square link. Thanks for that in advance.

    PS – congrats on your weight loss. I look forward to hearing about your new fitted pants!

    • Thank you, Martha! The last 5 lbs. is the hardest. Like I replied to Ann, the discussion is in the spring 6 pak thread, but I think the mods are going to move it to a pants thread.

  7. This is a huge struggle for me. I modelled my back curve with a flexible ruler and it needs a lot of depth. I have had quite good results with Burda in the past as their back seam is on an angle and the section which goes under the legs is quite deep. Not really deep enough for me. I need to do more work on this for sure.

    • Ruthie, what I discovered on this go-round is that the position of the extra depth makes a difference. Good luck to you! Burda has been my best starting point, too.

  8. Congratulations on your weight loss and thank you for this post. I have (unsuccessfully) tried a McCall’s P&P pants pattern – it was huge and saggy though I have a lot to fill a pair of pants! The Vogue fitting pattern was too small everywhere and I gave up. This started me on a drafting journey – but the starting points haven’t proved suitable so far. . However, I think I will try the other two you mention, Knipmode and Burda. I have used a flexible curve to trace crotch shape – and it makes interesting viewing!

    • Thank you! I also always wondered why I needed to do what amounted to a flat seat adjustment when my seat is anything but flat.

  9. Bearing in mind how much variation there is in ‘butts’ it is no surprise that the pattern companies have different curves, and also that trousers are possibly the most feared garments for a new dressmaker. They are a gift when you get the pattern fitting well though!

  10. Finding a pattern where the crotch fits is aggravating. Adjusting, muslins, the cycle continues. I discovered Connie Crawford’s pants patterns and they fit me well — I had to raise the center back seam an inch but other than that, a great fit. Her back crotch is a cross between McCall’s and Knipmode. It seems like most pants patterns are created for a specific body type–Connie knows my body (lol). Years ago, Burda pants patterns were great for me too.

  11. Thanks for an interesting post Robyn. I need to revisit pants. Eureka Pants That Fit is on my agenda, but I must be in the mood. Perhaps some meditation and the new yoga pose will help me focus!

    Another intersting wrinkle is that I have successfully fitted McCalls shorts to myself, but not long pants. ???

  12. I used to have so much trouble fitting pants that I went to classes to learn pattern cutting. But these days I use commercial patterns and find them OK. I am not sure why except that I invariably use fabric with a bit of stretch in it for trousers so I can make them closer fitting.

  13. Really interesting post and comments to match. Just when you get the perfect crotch seam then there’s the wrinkles at back thigh, the gaping waistline and every time you sew with a different fabric the fit changes all over again…….. Thanks

  14. You couldn’t be more right that fitting pants is not for anyone in a hurry. That made me chuckle (really rolling around on the floor would be a more accurate description). I’m a returned to sewing sewist (after a 40 year hiatus) and it wasn’t long before I was eyeing pants with gleeful excitement. What could be better than actually donning a pair of pants that FIT?! Especially at 63. So began my journey (2.5 years ago) with online classes and books and videos – am I closer? I think I am but I still want a pair of pants I like – I can make wonderful knit ones but that woven pair remains elusive. Sandra Betzina designs for Vogue but uses the Burda pant block in her patterns (she mentions this in her Craftsy pants making/fitting class which is excellent) and Barbara Emodi whom I admire a lot, in her recent book also gives out some great pant fitting advice. Your curve drawing was so interesting and what lured me to your post. Thank you for sharing that!

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