Pattern tweak help needed


Hey As i try to figure out how to proper draft and size patterns I have run into a small issue that is prop easy to fix. I am making skin tight leggings/pants and i’m having an issue where they are a little baggy in the crotch area. Specifically that spot that runs between the top of your hip down to your crotch/inner thigh. If anyone has an idea for this that would be great.

Jennifer Maillet.vit (4.4 KB) leggings.val (7.8 KB)


The short answer - in my opinion the pants are too long from the crotch to the waist, possibly only on one side. Either the wearer is slightly asymmetric or the pants are. It is rare to find any human who is totally symmetric.

I do not see a waistband on the pattern, nor on the picture. If I were fitting someone for a costume that looked like this and opening night was soon, I would grab a handful of pants and “hike them up” and see how they looked. If that made them look better, I would either add a waistband or adjust it if there already is one. Adjustment may include taking the waistband off, shortening the effect of “crotch length” in the pattern on the finished fabric, then resewing the waistband to make it shorter overall, possibly just on that one side.

A more considered answer is that I think the pattern needs to be made to fit first in a non stretch fabric then adjusted to work with a stretch. The tight fit is a design decision and it is implemented in the pattern by incorporating “ease”. The pant tutorial (which I realize I have not finished enough to post on the wiki yet) will result in a pattern with zero ease. That is good for checking fit. To make a real garment to wear, you would add “design ease”. Dress pants, for example linen, would have a reasonably close fit. Work pants, canvas or denim, would have several inches of ease to allow easy movement. Fashion pants (choices made because you like the way they look) may fit snug (like the ones you appear to be working on) if that is the choice you are implementing. It looks like you are using stretch vinyl.

On first glance at the pants it seems that the issue is that there is too much fabric in the vertical direction between the crotch and the waist. How sure are you of the accuracy of the measurements “crotch_length_f” and “crotch_length_b”? I noticed that in your .vit file, if I add the values you have for crotch_length_f + crotch_length_b, they do not add up to the value you have listed for “crotch_length”. If you look at the drawing (which you can see inside the tape program if you click “add known measurement” and use the cursor to scroll down through the measurements until you get to the section N - Crotch and Rise". I have included a screenshot those measurements should add up.


.Are you using any specific pattern making method? I am curious about which measurements you use and why. There are different methods. The one I uses the “rise” rather than the length measurements. You can probably find a book in a library. If you want to use the Don McCunn method, he has ebooks for around $15 (US). There is a link to several patternmaking resources in the wiki.
McCunn - Seamly2D
UserManual:Patternmaking References - Seamly2D

If I were doing the pattern, I would start by getting it perfect in a non stretch fabric, then add “negative ease” based on the stretch in the fabric. If you do a search on this forum for “HeloCortes” you will see an on line resource I found on how to measure the stretch percent in any specific piece of fabric. (It is under the topic “simple skirt pattern”.

So in an ideal world, I would make the pattern, sew it up in muslin (I cheat and use sheets from the thrift store) and get the pattern perfect. Then adjust the pattern to account for the negative ease of the stretch fabric. “negative ease” is just a fancy term that means that if it stretches, you might have a 20 inch elastic waistband that fits comfortable on a person with a 25 inch waist. Length = measured - (ease * measured) so if the elastic has a 25% stretch factor, that means the 20 inch length will fit a measured waist of 25.

M is 25 inch measured waist L is the length of the elastic E is 25% of L because that particular elastic has a 25% stretch factor “S”. E = -0.25

M + E = L
25 + (-0.25*L) = L
25 - (L/4) = L
25 = L + (L/4)
25 = 20 + (20/4)

I realize this is not as organized as I would like it to be, but I hope it is helpful.


Here is the screen shot that somehow was invisible in the previous post



That’s my thought too… when you look at the folds and where it’s pulling it gives an idea where there’s too much or not enough. So it’s either too long in the rise, or not enough in the seat.

Don’t know if this helps.


Still invisible. Is it a png? For some reason they seems to show in the preview, but don’t post. Annoying because the Windows screen print saves as png.


arg arg arg arg … 20 or more characters worth of arg


and that’s the trick :wink: They are made out of glued latex, no sewing. The stretch depends on the thickness of latex being used and this stuff is .35mm which is pretty standard for most stuff and has decent stretch. I made the pattern based on a tutorial that shows how to measure and make pattern blocks from scratch and used whatever calculation she had for using the measurements to get the rise. I don’t do positive or negative ease. basically I am making just pattern blocks and the width of the seams pretty well takes care of the negative ease. They have a rather high waist (belly button height). No waist band because it’s not needed. In order to get into these clothes you need to grease yourself and the inside of the garment with either lube or powder then wrestle your way in. Once you have it on and it begins to settle, it doesn’t move, it’s like second skin. picture trying to get in and out of a wet bathing suit.


I’ll go through this site and see if anything in the design changes vs what I have.



I am fairly sure that the issue is that you have too much length in the pants when compared to the body between the crotch and the waist. This appears to be only on one side. It is even possible, given what you just said about the material that you could fix this one by tugging on it before letting it “settle”.

Re: the measurement file, I still suggest that you take a look at why the measurements crotch_length_f (11) and crotch_length_b (12) when added do not equal crotch_length (27). If those measurements are precise, then the third measurement should equal the sum of the first two when added together. I suggest that you tie a ribbon around the waist and take the measurement of the total crotch_length with a second ribbon. (while wearing tight fitting underwear) Pick a spot where you want the front seam to meet the back seam and mark that spot on the second ribbon. Then take a tape or ruler and measure all three measurements from the second ribbon.


Agreed. You want the front crotch length plus the back crotch length to equal the “1/2 girth” as noted by kmf. The great thing with Valentina is that by looking in the variables table ( ctrl-T) you can find the length of curves from your crotch lengths and see if they add up to your measured 1/2 girth.


I will try again with a jpeg vs a png file to post the screenshot to illustrate section “N - crotch and rise” in the valentina measurement diagram.

To see the entire list of measurements recognized in the tape program, please see

@Douglas I haven’t found a reference in the last 2 minutes to define the term 1/2 girth, though I have heard it used as well. (can you point me to a source for that term. I am not questioning its validity because I also have heard it before)

I used the terms I did both because they are in the measurements diagram and because the are the specific measurements that were included in the .vit file from earlier in this thread. The issue of picking a patternmaking system and using THAT system to frame the discussion is important because there are many (perhaps equally valid) systems and they use different words to mean the same or similar things.



3 different theatres I worked with recently that have the 1/2 girth on their sheets…


I have requested costume plots from all of the major rental places sometime in the last 10 years and I am sure that that was at least one of the places I have seen it. I don’t doubt that it is widely used. I am just looking for a published source.


(Part of the problem with the girth measurements that I’ve seen -whether vertical or horizontal- is that they assume symmetry, which is rarely the case. Every time I see ‘1/2 waist girth/circ’, I just sigh and use the proper, contextual measurement.)


Well the reality is when you do business with various theaters and costume shops around the country and in NYC/ Broadway like I do, you’re going to have to deal with measurements like 1/2 girth…


@ladyinaz, Did you use hip_circ/4, or did use separate measurements for front and back hip_arc_f/2 and hip_arc_b/2 to make your pattern?

Wrinkles down the side of the garment occurs when the bottom is too wide or deep for the back half of the pattern. This puts strain on the side seams and the garment becomes skewed.


I used leg_thigh_upper_circ/2 to determine where the points of the crotch go crotch_length_f and crotch_length_b to determine the inseam to waist measurement then tried to add the curve according to the instructions i used (which is in a private part of a site and i can’t seem to find a way to share it.) i’m not sure if there is a rule of thumb for that or not.


@ladyinaz -
What was the measurement formula for the hip width for the back pattern piece?


I posted the .val and .vit in the original post if you want to have a look, might be easier to see what I did.


You’ve used proportions to create these leggings. Create a proper hip line, using hip_arc_f/2 for A10 and hip_arc_b/2 for A11. Then use your upper thigh circ to create the thigh width about 1" to 2" down the leg. You’ll see improvement in the fit.