If you’re learning pattern-making or trying to understand apparel development and want to ensure you aren’t missing important information, this post is for you.
Have you ever needed clarification on what seam allowance is? How much to add? When to omit it? What is it actually for? We will cover that and more in this post. I will also teach you how to add seam allowance in Clo3D if you're a Clo user! 😃
Put simply: Seam allowance is an additional line on a pattern piece. It’s the outermost line in the photo example shown above. The reason why it can be perplexing is that if you only see one line, it’s hard to tell if there is a seam allowance included.
Seam allowance is used in the physical production of sewing a garment. Seam allowance is the distance between the sew line and the cut line. The sew line or seam is the working line from which a pattern maker drafts the pattern either in cad or on paper. The sew line is literally the line that will be sewn later in production. These lines are the seams and when the garment is finally constructed, they are measured for quality control. The sew line may or may not be printed on a pattern piece.
In home sewing patterns, the sewing line is sometimes omitted from being printed out, but there is still seam allowance included. The reason why sewing lines may be omitted could be due to prevent confusion if the graded sizes are shown. Many times, patterns for home sewing are printed out nested or stacked with multiple sizes. Including a sew line in this instance may be difficult to read.
In production, pattern pieces are printed out differently from home sewing patterns. Home sewists typically cut and sew one garment at a time, so the home sewing pattern is optimized for being as compact as possible to fit in a small package. The home sewist then lays out the pattern pieces and makes several lays depending on the complexity of the garment.
Production patterns are printed so that the cutter can stack many layers, or plys, of fabric and go at it in one pass. If there are multiple fabrics, they will be on a separate print, but for the most part, there is much less fussing with production patterns as they are optimized for efficiency.
If you have a background in graphic design, you can compare seam allowances to bleed lines. In graphic design, you may have a poster that’s a certain size, but when it comes time to actually print out the poster, you will want to ensure to bleed the artwork beyond the dimensions of the poster. This extra allowance acts as a buffer so there’s no unintended white space. Seam allowance can be thought of similarly.
How much seam allowance to add?
There isn’t a standard amount of seam allowance to add however, many times, the amount of seam allowance helps determine what type of seam it could be. Three-eighths to a half inch are the most common and are often used for many seams, including straight stitch and five-thread overlock with safety stitch. a quarter-inch seam allowance is often used around neck seams or close on the serger. Three-quarters to one-inch seam allowance are common along bottom hemlines and bottom edges of sleeve openings at the wrist.
If there is a fold-back, note that the seam could be longer and may require mitering so the angle matches when folded back. Mitering the seam allowance is commonly referred to as a seam correction. These angles are a telltale sign that seam allowance has been included and help the garment come together neatly in production. Some edges may be left without seam allowance intentionally; this is sometimes referred to as a raw edge. It may be left raw as a design element, or it might be finished off differently with fold-over elastic or double-fold binding.
If you have a pattern that doesn’t include seam allowance, it can be added as the pattern is cut. However, it takes additional time to add it in by hand with a ruler and chalk than it does for a pattern maker to add it in a cad patternmaking software such as Clo3D.
How to add seam allowance in Clo3D
To add seam allowance in Clo3D, locate the Seam Allowance tool in the 2D window.
Select the tool and click on the segment to add the seam allowance. You can click and drag to select multiple segments or hold down the shift key to collect more than one selection at a time. In the Property Editor window, you can specify the width of the seam. You can also add a seam correction by selecting a point and changing the Intersection in the Property Editor window.
Let's collab!
Looking for a pattern maker to help with cad? I work with designers with a vision looking for help with the technical part of design and development. Let me know your project goals, and I will provide a quote for your unique project.
About the author:
Ellie Wilcox is the founder and CEO of Digitech Design which helps entrepreneurs with apparel design and development. Providing services in 3D renderings created in Clo3D based on cad patterns and sewn prototypes. Ellie started working in fashion and production in 2011 and has implemented 3D samples since 2016. Using 3D reduces the number of physical prototypes to get to market and lessens the fashion industry's carbon footprint.
📲 Follow me on Instagram @DesigningwithEllie
👩🏻💻 You can subscribe to the blog to learn more and stay updated on future posts!
Comments