The example shown below is the Skirt Back with two darts. The principle applies the same to the Skirt Front, or Pants Front & Back.
This is just to get an understanding of the curve; after a while you should be able to know what the curve will look like and draw without having use this tracing method.
This can be done either by using some tracing paper (Figures 01 to 04) or by pivoting (Figures 05 to 08).
Curving the Waist, Skirt Back - Figure 01
When you create the skirt, you start with a straight line for the waist, as in Figure 1.
Curving the Waist, Skirt Back - Figure 02
In order to create a curve, it is best to close the darts.
To close the darts two-dimensionally:
- trace the shape between darts A & B (shown in green), and
- trace the shape from dart B to the side seam (shown in yellow)
Curving the Waist, Skirt Back - Figure 03
- Pivot the yellow shape to close dart no.2. You will need to tape these pieces together.
Curving the Waist, Skirt Back - Figure 04
- Now pivot the tracing paper (which should be two pieces taped together, so they will move as one piece) on dart point 1, to close dart no.1. It should look something like Figure 4.
Curving the Waist, Skirt Back- Figure 05
- Put a piece of paper underneath the tracing paper, as shown, and stick the tracing paper onto the paper.
- You may also need to stick the tracing paper down on the dart line to stop it moving while you redraw the waist
Curving the Waist, Skirt Back - Figure 06
- Draw the waistline curve on the paper
Curving the Waist, Skirt Back - Figure 07
- Remove the sticky tape along the dart line (don't remove the stick tape attaching the tracing paper to the paper)
When you remove the paper and the tracing paper (stuck together), you should have something like this (A) in Figure 7.
- Cut out the waist curve from the paper - shown by the dashed black line in (B), Figure 7.
Curving the Waist, Skirt Back- Figure 08
- Extend the lines of the first two shapes up to the waist line (C).
- Cut along these lines, and separate the three pieces (D).z
Curving the Waist, Skirt Back - Figure 09
- Take those three pieces and place them / line them up on your block/pattern.
- Draw the waist shape, then you can remove the paper/tracing paper.
- Now we just need to finish shaping the darts, which we'll do in Figure 10.
Curving the Waist, Skirt Back - Figure 10
- Extend the mid-dart lines up some distance (shown as blue dashed lines in the image).
- Continue the curve A that goes from CF to the first dart until it touches the mid-dart line.
- Blend it down to join Curve B.
- Continue Curve B until it touches the mid-dart line of the second dart.
- Blend it down to join Curve C.
Curving the Waist, Skirt Back - Figure 11
Your waist curve is complete.