Drafting the Basic Bodice Block

What Is a Bodice Block?

A bodice block (also called a bodice sloper) is a plain, fitted pattern piece with no style design added. It is the foundation from which almost every fitted garment from the waist up is derived. A basic bodice set consists of two pieces — a front and a back — drafted directly from a specific person's body measurements plus a controlled amount of ease. Because the block is personal and precise, every pattern you draft from it will fit that individual far better than a commercial pattern sized to averages.

In tailoring and sewn-products production, mastering the bodice block is a core competency. Whether you are constructing a custom suit jacket, a fitted marine upholstery cushion cover with shaped seaming, or any structured sewn product, the principles of controlled measurement, squared lines, and verified seamlines transfer directly to professional-quality work.

Measurements You Need

Before you touch your L-square, record the following measurements on your personal measurement chart. Take each measurement over well-fitted undergarments with no extra layers. Write numbers to the nearest 1/8 inch.

• Bust — fullest part of the chest, tape parallel to the floor
• Back width — across the back from armhole to armhole at the fullest point, measured horizontally
• Chest width — front, armhole to armhole
• Back waist length — nape of neck (C-7 vertebra) straight down to natural waist
• Waist — natural waist, snug but not tight
• Shoulder length — neck point to shoulder point
• Armhole depth — standard reference value derived from bust measurement (see formula below)

Ease: Why We Add It

Ease is the difference between the body measurement and the pattern measurement. Two types apply here:

• Wearing ease — the minimum amount of extra room needed to breathe, move, and sit comfortably. Standard wearing ease for a fitted bodice is typically 2 to 2½ inches added to the bust circumference, split between front and back.
• Design ease — any additional room beyond wearing ease added for style.

The bodice block uses wearing ease only. Always confirm the ease value in the drafting reference you are following — Armstrong's Patternmaking for Fashion Design lists specific ease values for each formula step.

Setting Up Your Paper

Use dot-and-cross pattern paper from the 36-inch roll. The dots form a 1-inch grid that lets you measure rapidly without a ruler for every mark. Before drafting:

1. Tear off a piece at least 24 inches wide by the back waist length plus 6 inches tall.

2. Align one edge of the paper with a vertical line of dots — this becomes your center back (CB) line.

3. Use a red pencil for all construction lines and key points so they stand out from the working pencil lines you will refine later.

Drafting Sequence — Back Bodice

Follow each step exactly before moving on. After each step, stop and verify your measurement matches the formula value within 1/8 inch.

1. Establish the back length line. From the top of the CB, measure down and mark the back waist length. Draw a horizontal waist line squared off the CB.

2. Establish the back neck. From the top CB corner, measure across 1/6 of the neck measurement plus 1/4 inch and mark the back neck width. Square up about 3/4 inch for the neck rise. Connect with a shallow curve using the hip curve.

3. Establish the armhole depth line. From the top CB, measure down the armhole depth (calculated from bust: approximately bust ÷ 4 + 1 inch for most average figures; use your formula sheet). Draw a horizontal chest line squared off the CB.

4. Establish the back width. On the chest line, measure half the back width measurement from CB and mark.

5. Place the shoulder point. Using shoulder length and the neck point location, draft the shoulder seam line.

6. Draft the back dart. The standard shoulder dart or waist dart is placed and its intake is calculated from the difference between the back waist formula value and the actual back waist measurement at that section.

7. Draw the side seam. Connect the armhole underarm point to the waist point with a straight or slightly curved line.

Drafting Sequence — Front Bodice

The front is drafted adjacent to the back on the same sheet or on a separate piece, with the center front (CF) line running vertically.

1. Establish front length. Front length = back waist length minus 3/8 inch (standard formula adjustment for most figures).

2. Establish the front neck. Front neck width equals back neck width. Front neck depth equals back neck width plus 1/2 inch. Connect with a curved line.

3. Establish the bust line. Measure down from the shoulder the same armhole depth used on the back. Mark the full front bust width (half of bust ÷ 2 + ease portion) from CF.

4. Draft the bust dart. The bust dart is the defining feature of the front block. Dart intake = the amount the front pattern width at the bust exceeds the flat chest-width measurement. The dart is placed at the side seam pointing toward the bust point (apex).

5. True the dart legs. After drawing both dart legs, fold the dart closed on paper and verify the side seam is continuous — adjust if there is a gap or overlap.

Truing and Matching Seamlines

Truing means smoothing all lines so they flow cleanly from one point to the next and so opposing seams match in length. Use the vary-form curve for armholes and the hip curve for neck curves. Use the L-square to ensure all right-angle corners are exactly 90 degrees at center front, center back, and waist.

Matching side seams: Measure the front side seam and the back side seam from the underarm point to the waist. They must match within 1/8 inch. If they do not, re-check your waist calculations.

Safety in the Pattern-Making Lab

• Keep your work surface clear. A cluttered table causes mis-measurements and L-square slippage that can drive the corner into your hand.
• Tracing wheels with serrated teeth are a puncture hazard. Cap them when not in use and point them away from yourself and neighbors.
• When using a rotary cutter to trim paper, always cut away from your body on a self-healing mat, not on bare table.
• Good posture and regular breaks prevent repetitive-strain injury from extended drafting. Adjust your stool so your elbow is at table height.