What is a technical drawing?
A technical drawing, which is also called a computer aided design (or CAD), tech pack, spec sheet or line sheet, is a type of blueprint that’s used in the fashion industry by factories and pattern cutters. These blueprints show the garment’s shape laying flat and without any stylizing or artistic details. It includes important information like the type of stitch used and aspects of its shape like any trims, fastenings, darts or tucks. The CAD will usually only show the front and back of the garment, however sometimes the internal view is also necessary. For example, if the garment is a ski jacket, the blueprint will have to also show the positioning of internal pockets and so on.
What about illustrations and sketches?
Blueprints actually have many advantages over using a photo or sketch. First, because they would usually show how the garment looks on a model this can cause confusion about the real proportions the garment should have, and distort aspects like its height and width ratio. Another reason is that there just needs to be a higher level of detail in order to construct the garment well. Every stitch, seam, rivet, dart, etc needs to be clearly marked. The technical drawing is able to show the garment in its “flat” state, which is also how the factory will build it. This is crucial to allowing the factory to measure the garment’s proportions correctly, since the drawing will match the garment that the factory is actually looking at.
Having this technical drawing, as well as the tech pack, allows the factory to have an instruction manual they can use to create samples and quote a price for you.
Ideally you should provide the factory with two versions of the drawing, one in colour and one in black and white. Having the colour version will be useful for the production process if the garment has multiple colors. But the black and white version is crucial for the factory to be able to see construction details like the stitching, without being distracted by the color. Especially with dark-colored material that can make it harder to see important details. The black and white version is used with the measurements included in the tech pack. Using arrows on the black and white drawing will indicate where the factory should measure.
A technical drawing can seem simple at first but every detail of the construction is carefully shown. For example, how should the edge of the garment be finished? Options can include being left raw, a cover stitch, a single needle stitch, lined, bound, or faced? Every opening (such as the hem, cutout, neckline etc) has to be indicated, as will the technique for the style and fabric. The drawings can seem simple but there is an infinite number of decisions involved that have to be considered. The variations for different finishes that need to be considered will extend to whether the garment needs a zipper, are darts used for shaping, if the seams are adequate or will make the garment become too bulky, etc.
This little explainer gives you an overview of how much effort and detail is included in every technical drawing. But you’re very welcome to reach out with any questions that I’ll be happy to answer. Let me know if you’re interested in taking these first steps for constructing your designs or want to learn more about my services!