Sewing essentials: Dart manipulation
- Emma Cartmel
- Mar 6
- 4 min read
In this guide, I demonstrate two methods of dart manipulation—the pivot method and the cut and spread method.
Disclaimer: This article was originally published as a paid post for The Thread. The views and opinions expressed are entirely my own and based on my personal experiences.
Dart manipulation is a pattern making technique used to reposition a dart on a garment without altering or adjusting its overall fit. Essentially, it’s a way to move the shaping in your pattern to a new location.
Dart manipulation lets you customise a sewing pattern to suit your design preferences. Whether you want to move a dart to a more flattering position, integrate it into a seam, or eliminate it entirely.
I first learnt about dart pivoting at university, around 17 years ago. At the time, being quite new to pattern making, I found this concept absolutely mind-blowing. It unlocked so many new design ideas and potential for altering that basic block into something truly unique. Plus, it’s kind of fun—there’s something satisfying about seeing a basic pattern transform with just a few strategic rotations and cuts.
For this guide, I’ll be demonstrating two methods of dart manipulation—the pivot method and the cut and spread method. I’ve tried to create diagrams that are easy to follow when working manually or digitally.
Anatomy of a dart
A dart has two main components:
The apex is the point where the dart tapers and ends.
The legs are the diagonal stitching lines that connect the widest part of the dart to the apex. They determine the width and length of the dart, and therefore its overall shape.
Common dart positions on a bodice
The diagram below highlights some of the most common dart positions on a bodice block, though it’s not an exhaustive list.
Darts can be repositioned to various locations on the front bodice, such as the side seam, waist, or shoulder. They can also be incorporated into a princess seam line to eliminate them entirely.
While I am focusing on the bodice block in this guide, the principles of dart manipulation can easily be transferred to other blocks with the steps remaining largely the same.
Tools and materials:
Before you begin, I recommend gathering the following tools and materials:
Sewing pattern or block with an existing dart
Ruler
Tracing paper
Pencil and rubber
Scissors
Tape
Awl (optional)
The pivot method
In this example, I’ll demonstrate how to shift the shoulder dart to the armscye (armhole) using a front basic bodice block.
Step 1: Mark the new dart position
Note: For clarity, I have labeled the shoulder dart legs ‘left’ and ‘right’.
Start by drawing a line from the dart apex to the new dart position.
Step 2: Trace the pattern
Begin tracing around the block or pattern piece, starting at the top of the right dart leg (the dart leg furthest from the new dart position).
Continue tracing around the pattern piece until reaching the new dart position. Include the new dart leg in the tracing.
Remember to include any markings, notches or darts in this tracing.
Step 3: Pivot the dart
Place an awl or sharp pencil at the dart apex to anchor the block or pattern piece. This will be the pivot point.
Rotate the block clockwise until the left dart leg aligns with the beginning of the tracing from Step 2. This will close out the shoulder dart.
By doing this, the pattern will automatically open at the new dart location.
Step 4: Trace the updated pattern
Once the dart is closed, trace the updated pattern piece, starting at the new dart leg position and continuing to the top of the left dart leg.
Step 5: Blend and true the pattern
Add notches to the top of the new dart legs to ensure accurate alignment when sewing.
Blend and smooth the shoulder seam for a clean transition.
True the dart to refine its shape and ensure a precise fit. For guidance on truing darts, refer to my article “Checking, Blending, and Truing Your Sewing Patterns – Part 2”.
The cut and spread method
In this example, I’ll demonstrate how to shift the waist dart to the side seam using a front basic bodice block.
Step 1: Mark the new dart position
Note: Again, for clarity, I’ve labeled the waist dart legs ‘left’ and ‘right’.
Start by drawing a line from the dart apex to the new dart position.
Step 2: Cut the dart
Cut along the new dart position line, stopping 1–2 mm before the dart apex.
Carefully cut along the left dart leg, again stopping just short of the apex.
Step 3: Pivot and close the dart
Gently rotate the cut section anti-clockwise towards the right dart leg, closing out the original dart.
By doing this, the pattern will automatically open at the new dart location.
Secure the new dart in place with tape, wights or glue.
Step 4: Blend and true the pattern
Add notches at the new dart legs to ensure accurate alignment when sewing.
Smooth the waist line for a clean transition.
True the dart to refine its shape and ensure a precise fit. For detailed guidance, refer to my article “Checking, Blending, and Truing Your Sewing Patterns – Part 2".
Dart manipulation provides the flexibility to shape designs exactly how you want. Once you get the hang of it, it will open up so many possibilities. Hopefully, this article has inspired you to try it on one of your own patterns.
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