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A Crash Course On Dart Moving

February 3rd, 2007 by tatterdemalion

Someone by the name of Lola asked for help in figuring out how dart moving works; as such, I’ve tried to answer her specific questions. If someone else has a specific question that isn’t answered here, please let me know. (And Lola, if this doesn’t clear things up for you, let me know!)

It can be very hard to understand dart-moving in the abstract, so I suggest you work the examples as you read.

Start with a square of paper. Draw a dart out from the center. Here I used a dart that was 2″ wide, but it really doesn’t matter.

Square paper with dart drawn

Cut the dart out.

The dart has been cut

Close the dart, and tape it shut, as if you had sewn it shut.


See the shape it makes? Now un-tape it and lay it flat again. Make a straight slash, from the tip of the dart to the otherside of the paper.


Rotate the two pieces of paper so that the edges of the “dart” meet. Watch as the slash opens up on the other side. As you close the wedge shape on one side, it opens up a wedge on the other side–a wedge that is the exact same size.

Rotate the pieces

Now, try for yourself. Tape the slash closed, and tape the new dart shut. Is it the same shape as the original darted piece? Yep! Un-tape the dart, and keep working.

Now slash it again, this time from the center point to the right.

Slash to the right

Again, rotate the piece of paper to close the dart and open the new slash. The new dart is again the exact same size as the other two darts.

Rotating again

Tape together your old slash, and your new dart. Is it the same shape? Yep!

You can slash it again,

Keep slashing

and rotate it again,

Another rotation

but you’ll still always wind up with the same shape when you tape it together. No matter how or where you slash it, you are always removing the same thing, and just moving the other pieces around.

All the pieces

You can join the pieces together, in terms of pattern drafting, in different ways. You can butt the pieces together, and cut them as one from a piece of cloth. Or you can seam them together. But it’s always the same amount of fabric, with the same amount taken away, and it will always make the same shape.

So what are some practical examples?

I made a card-board cut out of a basic bodice sloper, and traced around it as I manipulated the darts. (In some places it appears the darts don’t meet; they do, but my pen wasn’t narrow enough to get in the cracks when tracing.) You probably have quarter-scale samples of slopers or blocks in your drafting textbook, and you can trace them out and work along with these sameples to better understand how it works. Here’s some basic bodices:

Basic bodices

I don’t know how your drafting method had you draft your basic bodice. Some have just the horizontal dart, some have both darts, and some have just the vertical dart. Any one of them can be changed into the other. In the picture above, I show how to take a bodice with only a vertical dart and change it into a bodice with only a horizontal dart: slash a line for where the new dart will be. Rotate that corner of the pattern. The middle image shows what the pattern looks like while rotating the piece; if you stop right there, you will have a bodice with both a veritical and horizontal dart. If you keep rotating it, you will wind up with just the horizontal dart.

Just like with our practice square, it still has the same amount that is there, and the same amount that is not. It’s just re-arranging it. If you sewed together the bodice on the left, it would fit exactly like the bodice on the right—or the bodice in the middle.

How about when a garment doesn’t have darts—only seams? Where is the shaping then, and how can it fit like a garment with a dart? Look at this sample:

Princess seams!

Here we start with a bodice with one vertical dart. We slash open to the shoulder line. We rotate the pattern piece half-way, so we have one vertical dart from the top pointing down and one vertical dart from the bottom pointing up. Two darts, the same amout of shaping as in the first image. But what happens when we simply seperate the two halves of the pattern?

Princess seams! There will be no “darts” in the garment, just “seams”. But the same amount has still been taken away, and the fit is still the same. This often referred to as “darts hidden in the seams” or “shaping in the seams”. When the garment is sewn up, you won’t see a “shaped” seam; you’ll see a “straight” seam. But if you take the peice apart, and lay them flat, you will see that the pieces don’t match; there’s space between them–darts!

Darts can moved to just about any place imaginable. Here a few examples; all of them are perfectly valid and will produce the same fit.

This sequence starts with one horizontal dart, in the typical under-arm posistion. It can be rotated to the center front. Or it can be rotated to the neckline. All three bodices will have the same fit; the same amount is always taken away, and the rest is just rearranged.

dart progressionfinal posistion

You don’t have to have only one dart. You can have two darts,

two horizontal dartstwo vertical darts

or three darts,

three darts toward the bottomthree darts toward the right

or, if you want, even more. When the darts get small enough (because there is so many of them; the more darts you make the smaller each dart will be, because you are never taking away more—just redistributing it), they are referred to as tucks.

Now, at this point, you may have stumbled upon a problem. When we practiced with a square, it was easy to see that every new wedge opened up was the same size as the old wedge that was closed. But when you rotate darts on an actual bodice, it looks like the darts wind up all different sizes–smaller darts horizontally and larger darts vertically.

Let’s look at another paper example. Here’s another piece of paper with the same two inch dart taken out. But this piece of paper isn’t a perfect square; its a rectangle (legal sized paper, to be exact!)

rectangular paper

If we tape this dart together, it look simlar to the shape we made with the square piece of paper. The only difference is that it has a lot more length on one side.

the new shape

Un-tape the shape, and slash and rotate as before.

rotate the dart to the other side

Looks scary, doesn’t it? The second dart looks so much bigger than the first dart, it’s hard to imagine it can possible get taped into the same shape again. But watch this:

the wedge still fits!

The wedge still fits! All the length past the wedge is length that is longer than the original square, but the new dart is still the same angle. If the paper was equally long on either side of the dart point, both darts would be the exact same size in angle and length and width.

And, if you tape the slash and the new dart, you will see that you still have the same shape you started with.

Now, the question you asked about was actually concerning skirts, so let’s look at some skirt examples.

some basic skirt manipulations

The image on the left is a basic front skirt sloper with one dart.

The middle image shows that if you made a slash straight down from the dart point and seperated the pattern pieces, you could have a princess seamed skirt. You wouldn’t “see” a dart in this skirt if you sewed it up (just a straight seam), but it would still have the same shaping. By adding a superflous straight seam at the end of the dart, it disguises the dart as just being part of the seam.

The image on the right shows what happens when you close the waist dart and open up a dart to the hem. Just like on our rectangle example, the dart appears much larger, but it’s really the same angle. If you sewed that dart up, the last image would fit just like the first image. But if you leave that dart un-sewn, you would be adding fit near the waist (subtracting fabric away from there), and fullness (adding more fabric) to the rest of the skirt. In otherwords, you would be making an A-line skirt–fitted through the hips, and then sweeping out!

I’m not 100% sure what you were referring to by “a bell-shaped skirt”. Perhaps you just meant an A-line skirt. Or you might have meant a style like this:

bell skirt

My drawing skills aren’t so hot, but you can see a rough sketch in the lower right corner what this pattern would sew up like: It would be fitted (and curved) through the hips, fall straight for your desired distance, and then flare out into almost a flounce. The dart is still there; a line is slashed straight down, and the pieces are seperated. Then equal wedges of fabric are added near the hemline on every seamline. The seam lines are all the same length as their corresponding pieces. When you sew them together, they won’t look like shaped seams–they’ll look like straight lines, as in my sketch. It’s only with the piece laid flat that you can see there is fabric subtracted near the waist, and fabric added near the hem.

Does that help?

Oh, and as a final note, when someone speaks of “rotating the dart to the side seam”, they are essentially doing this:

Moving darts to the side seams

I cut our original triangle in half, to show how it’s still the same amount being taken out. The one difference, though, is that darts point to the bulge. Since in this example the extra fabric is being taken out at the sides, instead of the middle of the fabric, you may find the fit changes.

Posted in Tutorials | 28 Comments »

28 Responses

  1. Annie Says:

    I found this tutorial from PR. Thank you so much! I’ve taken some PR classes with small gains in understanding, but yours is what I should have read at the beginning.


  2. Rita Says:

    Great tutorial. This clears up a lot of issues for me but I still have a hard time understanding “rotating the dart to the side seam”. Guess I’m just a slow learner.

  3. Jan Says:

    Thank you so much for taking the time to do this!
    That clears up a whole lot of questions for me!

  4. Tatterdemalion Says:

    I’m glad this has been helpful to people!

    Annie, your really couldn’t have read mine first. I just finished it less than 48 hours ago.

    Rita, I will do a more in-depth “how to rotate darts to the side seam” this week.

  5. Jane S Says:

    Wow, what an easy to understand explanation with terrific visuals. Thanks!!

  6. WOW!! Says:

    I really want to thank you so, so much from the bottom of my heart! I hadn’t logged on to PR just til now as I wanted to leave anough time for your response! I really wish you were my pattern tutor! I just don’t understand the way she explains things and she thinks I dont have enough confidence to try things out and make mistakes, but for me, I really need to understand the basic principles first before I can experiment. The skirt shape was exactly right! At the moment I’m working on a top, to be created from the basic bodice – I didn’t understand why the dart wasn’t in the shoulder but was to be moved to the bust, so I’m going to go through your tutorial step by step tomorrow morning when my brain is fresh. You really have a gift for explaining- especially as pattern drafting is a difficult subject! Thank you so much, you’re wonderful !!!

  7. Lola Says:

    sorry that, last comment from Wow is Lola

  8. Tatterdemalion Says:

    Lola, I’m very happy this has been helpful for you!

    You are exactly right that if you don’t understand the basics, you won’t be able understand the rest.

    I would be glad to try to help you with any other pattern drafting questions you might have. Just remember that the more specific and detailed your question is, the better my response is able to be. (That might be helpful to keep in mind when working with your pattern tutor, as well. Any teacher will have a hard time explaining things if they don’t understand which part confuses you.)

    Let me know if there is anything else you need help with!

  9. Bernice Says:




  10. I take your questions and do my best to answer them, vol. 2 » The House of Tatterdemalion » Blog Archive Says:

    […] Bernice recently left a comment on my “Crash Course on Dart Moving“. […]

  11. deepa Says:

    excellent explanation………I teach in a fashion collage…..and it helped me a lot

  12. tatterdemalion Says:

    I love making those tutorials, so please take me seriously when I say “Let me know if you have questions” or some other topic you’d like me to address.

    Here are two others I’ve done:

    This one is what I call my “illustration of the origin of darts, where they came from, how they got there, what they’re doing there, and what happens when they leave

    This one is my more indepth look at moving darts to the side seams:

  13. kelly soo Says:

    Wow! U did such a great job with this crash course! It truly reminded me of all my past college work, even better!
    Thank you

  14. tatterdemalion Says:

    Thanks Kelly! It always tickles my fancy when people say it helps them with their school work. . . I taught myself, so it’s fun to know I’m on the right track!

  15. Antonio Castillo Says:

    This is an excellent dart manipulation tutorial. The only thing that you don’t mention is that the center of rotation is the bust point. However, it is sufficient for people do some practice and grasp the process of changing the position of the dart.

  16. tatterdemalion Says:

    Thanks. . .though I didn’t specify what the center of rotation was on purpose. On a top it would be the bust point, but on a skirt or pants. . .it wouldn’t be. 😉

  17. Felina Says:

    *Now* I get it! Excellent explanation. I’m definitely checking out the rest of your site and am sharing this with friends.
    We are belly dancers and pretending to be seamstresses… so much to learn!

  18. tatterdemalion Says:

    *blush* I’m embarrassed at how long it’s been since this I’ve updated or worked on this site. . . it’s in terrible condition. The good news is, the nature of darts hasn’t changed at all, so I’m glad people are still finding this tutorial helpful.

    Good to hear from you, Felina! I only pretend to be a seamstress, too, so you’re in good company. (In real life, I’m a Physical Therapist Assistant. Sewing is my hobby!)

  19. Dee Davies Says:

    I love sewing cushions and stuff for the house. I make the occasional plain dartless top for myself. I would like to be able to make my own clothes but would never be able to get my head around making a pattern.

    I would happily pay for a block pattern in my measurements and wonder if you would consider this. Or if you know of someone else that would do this for me.

    I hope you don’t mind me asking you.


  20. tatterdemalion Says:

    Hi Dee!Sorry for the long answer to your question, but–the short answer somewhat comes down to how determined you are.

    I can draft accurately to any measurements, but the measurements need to be accurate in order to to actually have a block that fits. Unfortunately, you need a lot more than three measurements to draft a block. If my memory serves me, its actually something like 32 different measurements! To be perfectly honest, I dread the measurement taking part more than the pattern drafting part. Human beings are shifting, moving objects, and it can be difficult and time consuming to get truly objective and relative measurements.

    Does that mean you can’t do it? Nope! I did it. I taught myself. If I can, you can. But it did take me several attempts, a lot of time, and a very patient sister. If you are interested in seeing what sorts of measurements you’d need, beg, borrow or steal (just kidding–how about buy or inter-library loan?)a copy of Elizabeth Allemong’s European Cut ( ). This is the book I taught myself to draft from, and the first whole half of the book is devoted to explaining how to get the measurements you need, in very helpful, no nonsense, accessible instructions. If I were to draft from your measurements,you’d need to take the measurements as she describes.

    And while you’re looking at the book, you might want to look at the other half–the half that talks about how to draft. Really, if you can divide fraction and use a straight edge, you can draft a block. Elizabeth’s instructions are very clear and simple, and if you follow them step by step, very easy. If you have accurate measurements, your draft will fit.

    If you do get your hands on her book, and do decide you want to go for the project that is getting accurate measurements, and after reviewing the drafting instructions you still think drafting would give you the heebie jeebies–let me know. Maybe we can work something out!

    But you have to go into this realizing that it would be a Project, even if you weren’t doing the drafting. If you are up for a Project, and are motivated to see it through, I know you can do it.

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  22. Perl Says:

    This is amazing guide, thank you for all the clear examples! I am working on my own bodice sloper/block right now and have been scared to rotate a dart of excess fabric from the armscye (pointing to my bust) to a waist dart because I just can’t see how changing the position of the dart wouldn’t affect the shape. I think I can do it now.

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  25. granny Says:

    I understand how to move darts that are pointing to the same point but what about parallel darts like on a skirt pattern I want to split one dart into two.

  26. Queen Says:

    This was very detailed and very helpful, thanks for taking the time to do this. I’m so glad I found your page.

  27. tatterdemalion Says:

    My pleasure! 🙂

  28. tatterdemalion Says:

    Argghh! I’m finally sorting through mountains of spam comments and finding some really good questions that I feel rather horrible for missing! Granny, good question, and if you see this now almost two years later, I hope to write up another blog post with the answer to your question. It looks hard to split darts, but it’s actually quite easy. . .but I need illustrations to show you how and I can’t do that in the comments.

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