Adapting a pattern to the chest: the classic dart

Before modifying a pattern at the chest level, it is advisable to refer to the article “The basics of a chest transformation”.

The technique explained in this tutorial allows you to enlarge the front pattern so that the garment fits perfectly at the chest level. Depending on the structure of the pattern, the modification will not be done in the same way. Here we will see how to enlarge a bodice with a bust dart tilted on the side line.  If the bodice needs to be reduced instead of enlarged, the technique will be the same. Instead of spreading the lines apart, they will need to be overlapped.

Basic material to perform a transformation
To transform a pattern, it is advisable to have:

• Adhesive tape

• A parrot rule

• A square

• A graduated ruler

• A support sheet

• A pair of paper scissors

• A fine-tipped pencil/criterion

Construction of transformation lines

• Locate the location of the chest clip.

• Mark a mark in the middle, at the base of the clamp on the side.

• Draw a line A connecting the previous point with the tip of the pliers.

• Now find the apex point (tip of the breast) corresponding to your own morphology. Normally it should be in the extension of line A. To know how far to place it from the tip of the clamp, place the paper pattern on your body and mark a point at the level of the tip of your breast, on line A. This point will serve as a basis for the transformation of the pattern.

• From the apex point:

• Draw a biased line B ending at the armhole.

• Draw a line C parallel to the straight grain and to the center front, ending downwards.

• Then draw a horizontal line D, perpendicular to the straight grain and to the center front. Place it between the center front and line C. The height of the location is not important.

  

Transformation of the boss

• Cut along line A, stopping 2-3 mm before the apex point.

• Cut along line C to the apex, then continue along line B stopping 2-3mm before the armhole line.

• Line D will be cut later. 

• Place the pattern on a large sheet of paper. Pin the right side of the pattern to the paper. Use a few pins or tape to position it at the center front, at the neckline, and along the shoulder.

• Slide the other parts of the pattern so as to separate the chest dart and the axis passing through the apex point. Separate the left part of the pattern by the amount necessary for the enlargement, taking line C as a reference. The dart should open naturally.

• Fix all parts on the paper.

• Then cut along line D. Align this small, completely separate part of the pattern with the rest of the piece, at the hem.

• Attach this element to the paper support.

  

Adjusting the parts

• At this point, we observe that the bottom of the front has widened proportionally to the measurement added to the chest.

  It is possible to keep this width only if a hem is planned at the bottom of the piece.

  Otherwise, you will have to trace the side from the clamp to the bottom, removing the excess value.

• Extend both sides of the pliers to the tip.

• Then check that the side seams of the front and back are the same length.

  If the front pattern includes a lining or a facing, you will need to transfer the modifications to these pieces.

After all these modifications, it is advisable to carry out a test in a canvas before starting to make your garment.

Case of a boss without a clamp

It is also possible to apply this transformation to a pattern that does not have any darts. Draw line A anywhere from the apex point to the side. Once the pieces are tilted, the gap forms a dart that must absolutely be kept. The pattern without darts therefore becomes a pattern with darts.