Pattern Making Fundamentals: Understanding Darts

Designer Akira Isogawa in his studio, image from NLA.

Whenever you see photographs of designers in their studios you are bound to see rolls of fabric, scissors, pins, sketches… and often these curious looking racks of brown cardboard (to the right of the image above). These are the designers patterns, the 2D representation of the 3D garment and the tool that allows designers to recreate the garment exactly the same time and time again.

Essentially the pattern is a template for each piece of the garment, such as front, back, sleeve etc. These pieces are laid on top of the fabric and cut out so that the fabric matches the shape of the pattern and any additional instructions, markings, button placements etc are normally also on the pattern.

The fundamental idea of how to approach pattern making all stems from what a dart does to a piece of fabric. A dart is a small triangle of fabric which is effectively pinched out in order to turn a flat piece of cloth into a mouldable form capable of going around all the curves of our body.

I have illustrated the basic principle below on a simple sheet of paper so that even if you have no sewing equipment at home you can start to understand the reasoning behind patterns. Note this is a representational exercise only, this is not pattern making technique but an exercise in understanding the principles behind pattern making.

These notes relate by number to the images below:

Take a piece of paper, and if need be make it into a square.
Fold the bottom left corner of the paper across to the top right corner, crease and unfold.
Fold the bottom right corner of the paper across to the top left corner of the paper, crease and unfold.
Make a mark in the centre of the two creases.
From this centre mark draw a line straight down to the bottom edge of the paper. Then draw two more lines out to either side. It does not matter how far apart the two lines are but make them the same distance from the centre line. This triangle is what is referred to as a dart.
Crease the line on the left with your fingers from the bottom of the paper up to the centre of the page by pinching the page. Now fold this line over to meet the line on the far right, pivoting the folded triangle off the centre mark. Sometimes this can be hard to crease, but this step can be helped by placing the centre mark onto the corner of a table.
Once the dart of paper has been folded out, your paper should look like the No. 7 image below. It should no longer be able to sit flat on the table because of the dart, and should form more of a cone shape. This is the basic shape that is used to create form in fashion, especially if you imagine this technique used around the bust area.
Now you can draw lines similar to the ones drawn on image No. 8 and you will begin to see the shape of a pattern emerge. Keeping the dart folded flat, cut along the dotted line indicated.
The remaining shape should look like the one in image No. 9 while the dart is kept folded.
Image No. 10 represents the pattern when it has been flattened back out and if you fold and unfold the pattern you will be able to understand how the dart helps make 2D paper into a 3D shape.
In the final image you will see what this cutout pattern represents – this is essentially the shape of a pattern which you would use for one front half of a basic women’s top or bodice shape.

The term ‘bust point’ is used to describe the highest peak of a womans bust and this is essentially the mark that you made when you made the centre point mark on your paper. If you cut this shape out on a piece of fabric (though not to scale!) then by sewing out the value of the dart you would start to create forms that curved with the body, and not sat flat against it.

The images below represent the shape of actual front and back patterns that you would use for making a womenswear top. These are the basic shapes or ‘blocks’ that fashion designers use to develop interesting shapes.

Here are some examples of old pattern covers, with illustrations that show examples of darts. The darts will be seen on the garment pointing towards the bust point of the woman, from the side seam or hem.