A comprehensive explanation of the flat pattern making basic foundation blocks.
The basic foundation
The basic foundation patterns start as either paper (flat pattern making) or muslin (draping). The dimensions for creating the pattern are determined by the end-use of the blocks. For example; an apparel company would use the dimensions of their fit model. If you are interested in designing and creating patterns for yourself, you would use your own set of measurements. Print this handy body measurement guide for keeping track of all your important measurements.
The shape of the foundation
Foundation patterns use the dimensions of the body to create a series of two-dimensional straight and curved *lines. When said lines are connected and later sewn together in fabric, they will create a three-dimensional garment that is tailored to the body. To put it plainly, a series of points are plotted (from the body's measurements) and the dots are connected to create a flat pattern.
*Examples of straight lines would be side seams, shoulder seams, and lines below the hip. Examples of curved lines would be armholes, necklines, and hip curves.
All About Darts
Oftentimes, in woven apparel, a series of “wedge” shapes are used to manipulate the fabric into a shape that will fit the three-dimensional form. These “wedge” shapes are called darts. Darts create shape in woven apparel by removing unwanted fullness at the edge of a pattern. Darts are most often used around the bust, waist, hip, shoulder, abdomen, and sometimes the elbow. Darts are not only used for tailoring, they are also used for design purposes.
Sloper vs. Block
Are a sloper and a block the same thing? Sort of. Let me explain….
A sloper is considered to be a basic fitting shell, drafted from your body's measurements. It is meant to be a close-fitting garment with an impeccable fit. It will have very little wearing ease, no seam or hem allowances, and no design details. Basically, it’s like a second skin.
The sloper is used to create blocks. While they are very similar, and often used interchangeably, there are a few key differences…
The block is drafted from the sloper and includes wearing ease. Blocks come in a variety of styles. For example; a new block would be created for a jacket, a blouse, a trouser, a dress, etc. Just like slopers, blocks will have no seam or hem allowances.
The purpose of blocks is to perfect the fit of any given style with the intention of creating new, more unique styles from said blocks. The concept is to have a good fitting shell, and when design details are applied, the same fit will be transferred into the new styles.
Pattern Drafting A system of creating patterns that reflect an individual’s measurements or the sizing standards of an apparel company.
Flat Pattern Drafting A system of making flat, 2 dimensional patterns that when sewn together create the desired fit.
Pattern “Blocks” or “Slopers” A collection of foundation basic patterns usually consisting of the front and back bodice, front and back skirt, sleeve, and pants. Pattern blocks have been tested to have an impeccable fit. All new styles and patterns stem from the basic foundation. In other words, basic blocks are altered to create a variety of new styles.
Creating the basic pattern block The basic foundation starts as a 2-dimensional flat pattern. It is drafted on paper and the dimensions are taken from a model, your own body, or a company’s sizing standards. These measurements will dictate the basic shape of the patterns.
Pattern Shapes Pattern blocks are created with a series of straight and curved lines. These straight and curved lines create a pattern by applying the individual measurements and “connecting the dots”.
Flat Pattern-Making Terminology
Apex The highest point of a dart or a curve.
Armscye The point on a pattern in which the sleeve is sewn.
Blend Blending is a process of smoothing and shaping lines to create a smooth transition from one point to another. Similarly, blending can occur when connecting two separate lines or curves to create a pattern pieces. An example of this would be connecting a bodice block to a skirt block to make a dress. This is usually done using the common pattern-making rulers.
Bust Point A designated place on a pattern that is generally used as a pivotal point. For example; when moving a dart to a new location on a bodice.
Bias A diagonal line across the grain of the fabric. A bias cut is generally used in knits and has a desirable drape that fits closely to the curves of the body.
Blocks Pattern-making blocks generally refer to the individual pieces that together create a sloper. Blocks do not contain seam allowances, hems, or facings. Sometimes, block and sloper are used interchangeably. However, in the apparel industry, there is a distinct difference.
Dart Triangular elements of a pattern that when sewn enable a flat, two-dimensional pattern piece to take shape on a three-dimensional figure. Not all garments use darts. For example, knitwear does not require as much built-in shaping as a woven fabric would need.
Dart Leg Two lines that come together at a specific point to create a dart.
Dart Intake The portion of the fabric between the dart legs to remove excess fabric and create a shape.
Ease The amount of extra fabric that is built into the pattern to allow the garment to fix in a relaxed position. A woven pattern would have positive ease, whereas a knit pattern would have negative ease.
Facing An extra pattern piece that is used to stabilize an area of a garment. Facings are often used around curved areas such as neck and arm openings.
Grading The process of creating the sizing of a pattern.
Grain The direction of the threads in a woven fabric, or the lengthwise, long warp threads.
Muslin A plain weave, unbleached cotton fabric available in a variety of weights. It is used to perfect the fit of a pattern before the slopers, or final patterns are created. Muslins are used for fit and are commonly torn apart or drawn on to reflect desired fit adjustments.
Notch Symbols or markings are used on a pattern to indicate cutting lines, joining points, hems, dart legs, CF (center front) and CB (center back), etc. There are a lot of pattern markings and this is covered in the pattern markings article. Single notches refer to the front of a pattern and a double notch refers to the back of a pattern.
Seam Allowance The area added to a pattern to between the cutting line and the stitching line allowing for a specific amount of extra fabric. The amount of seam allowance differs for the home sewer and the apparel industry. Leaving more seam allowance gives the home sewer more opportunity to adjust fit after a garment has been constructed, whereas, in the industry, companies want to improve yield and therefore use less seam allowance.
Sleeve cap The curved top section of a sleeve that when on the body fits just over the shoulder.
Sloper Basic apparel patterns without style lines or seam allowance are used at the beginning of the pattern-making process to create new styles. They contain all the necessary pieces to create a new style. For example; a button-down shirt would have a front and back bodice, sleeve, cuff, placket, and collar. Slopers are also called master patterns, foundational patterns, or standard patterns.
Trueing A process in double-checking that all measurements, seams, etc. are of equal length.