Design & Patternmaking

Fashion Design 101: How to Manipulate Darts on a Bodice for Princess Seams

As a longtime garment sewer one of the most rewarding and fun things to do is to create my own designs. I get a kick out of taking a basic pattern that I can manipulate to create something entirely different and all my own. You can do it too! All it takes is a little know-how and a desire to try something new. How’s it done? It’s as simple as converting a few darts!

Learn how to create your own designs just like the pros with this simple technique.

Add Gathers to a Side Panel

Craftsy instructor Suzy Furrer manipulating a pattern in her class Patternmaking + Design: Creative Darts & Seam Lines

Many of the designs I “fashion” are from something I’ve have seen in ready-to-wear, but nevertheless, I’m still doing what true designers do everyday. The pros start with a basic sloper, which they then convert into their stylish designs. Darts become princess seams, gathers, tucks or cowls. New style lines are added or moved, necklines are reshaped — you get the picture.

Darts are typically a starting point for creating new looks. They are the most basic form of creating shaping in a garment and are what turns flat two-dimensional pattern pieces into three-dimensional forms. Without them, there’s no room for body parts that protrude or curve, like the bust or hips.

Converting a Basic Sloper to Create Your own Design!

Creating a new look typically starts by moving or converting standard bust and waist darts. The process is surprisingly easy to do (even the beginner sewer!). Darts can be moved from the standard side seam position to the neckline, shoulder line or armhole. The same dart can also be converted into many other forms of shaping, like princess seams.

There are various ways basic bust and waist darts can be converted, moved or adjusted to either create new designs or to adjust fit. Let’s start with learning how to convert standard bust and waist darts into princess seams.

Note: The following instructions are for princess seams that start from the armhole, but the process is the same for those that begin at the shoulder or neckline.

Here is how to convert bust and waist darts to princess seams:

1. Begin with a basic sloper-style bodice with a side bust dart and a waist dart that has been adjusted to fit your bust. This is important for an easy transition to princess seam that will fit properly.

Bust point marked on basic sloper
2. Starting from the center point of each dart at their widest end, extend the dart points until they cross one another. This is the dart point.

measuring basic sloper with curbed ruler
3. For a princess seam that starts from the armhole, draw a line using a curved ruler from the center of the armhole to the bust point. Draw a notch or cross line 2 inches above the dart point. This will help when sewing the two sections together.

Extending princess seam to bust point
4. Extend the new princess seam from the bust point to the outer edge line of the waist dart nearest the center front.

Cutting along the new princess line
5. Cut along the new princess line from armhole to waist. This now creates a center front panel and a side front panel.

6. Cut along the lower edge line of the bust dart to the bust point (not the dart point). Bring the cut edge to the top bust dart leg and tape in place leaving a scant 18” spread at the bust point.

7. Fold out or cut out, the waist dart from the bottom wide edge to the bust point (also not the dart point).

8. Align the two pieces together matching the bust point and mark a notch or cross line 2 inches below the bust point.

9. Add grainlines to each section. For the center front panel the grainline should be parallel to the center front seam, or fold. For the side front panel the grainline should be perpendicular to the waist edge.

10. Last step: Add seam allowances to both sides of the new princess seam.

Learn advanced patternmaking skills with lifetime access to lessons from the founder of Apparel Arts Suzy Furrer. Learn to draft darts, gathers, ruching and seam lines in her online Craftsy class Patternmaking + Design: Creative Darts & Seam Lines!

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Where the sloper does not have the side bust dart, what is the best way to derive the bust dart? Thanks.

Kyle E

I know this comment is from over a year ago but I thought I’d answer anyway and maybe it will help someone else.

If your bust dart is coming from the shoulder or armhole, to move it to the underarm, cut a straight, level line across the bust line from the side seam to the bust point (perpendicular to the centre fold). Then cut your original dart, but leave it attached to the pattern piece at the last 3mm or so at the bust point. Then you just swivel your pattern piece between the two cuts to join them together. This closes the original dart and opens a new one the correct size while keeping all your other lines at the correct angles.

Remember to reduce the length of the new dart by 2cm to avoid pointy Madonna boobs.

ohikhena mercy

really enjoyed tis post do u have a tutorial on how to draft a personal sloper.

Agboola bose

I love this site and would like to take this course. How do l go about it

Bose Omotoso

Just go to sign up for and buy the class or just click the sign me up button above


I took a course from a seamstress when I was in high school. My lined vest pattern had darts and I wanted princess seams but she told me I had to get a different pattern. So I brought it home and my mother showed me how. This brought back fond memories.

Linda Reynolds

Glad to hear. Darts are easy to manipulate and give the sewer many creative options. Thanks for reading the post.

Valerie hall

I was reading up fashion design 101 manipulating darts to princess seam. When I got to section 6 I got confused as it says to leave a scant 18″ spread at bust point. Could you just explain where the 18″ is from. As I couldn’t calculate it. Thanks very much. I don’t think I’ve misread it .regards from val hall


I have just the same question and difficulty as Valerie hall about the spread of 18. Could you pls clarify
this point? Thank you in advance.


I think she meant 1/8″, not 18″.


merci de voir des cours sur bustie et comment des plies


It was going really well for me until there stopped being pictures. I have a very difficult time visualizing things.


Still very good stuff tho


i need some one to teach me to cut perfectly fit the pattern😐

Rashmi Shah

Thanks. Can you upload any vedio on this? I think it will be very useful if you show that way.
Thanks once again


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