The tech pack: the bridge between design and the workshop

What you will learn

Understand what the production tech pack is, why it works as the contractual document between design and the workshop, what kind of information it brings together in broad terms, and how the weight of that information changes depending on the garment category.

Before you start

You don't need to know patternmaking or industrial grading for this lesson: it is enough to have thought through the design of a garment at some point to understand why, before sending it to production, that idea has to become a document anyone in the workshop can follow without asking you anything.

Concept

When a design leaves your head, the paper or a fashion sketch on its way to the workshop, something has to happen in between: someone has to translate that idea into instructions that anyone in the workshop can carry out without needing to ask you anything. That "something" is the tech pack, also called a technical specification or spec sheet: the document that brings together the measurements, materials, processes and finishes needed to make exactly the garment you designed, not one size or one shade of color off. It is not a patternmaking document and it doesn't replace the pattern: it is a communication and traceability document. It works as a technical contract between design and production, because it proves what was requested, what was approved and by what criteria the finished garment will be accepted or rejected. A complete tech pack can be put together in 2 to 4 hours using an organized template; for complex designs, with several colors and size variants, it takes longer.

Lesson content

Why design alone isn't enough

A design that exists only in your head, in a sketch or even in a finished pattern leaves gaps: which supplier does the zipper come from? How much margin of error does quality control tolerate in the bust circumference? Without that data in writing, every production cut is resolved "at the workshop's discretion", and that creates variation between lots — something that in series production is a real problem, not a minor detail.

The tech pack covers three functions that design alone doesn't: it removes ambiguity (everything is written down, not in the designer's head), it is the basis of costing (fabric consumption, the quantity of trims and assembly time come from there, not from the pattern), and it is the documentary proof of what was requested if something goes wrong, for example a garment that is mislabeled or has a size that doesn't match the declared chart.

What kind of information it brings together (the overview, not the step-by-step manual)

A complete tech pack organizes the information in blocks that repeat in any category: header (identification of the style), size chart, materials, consumption and yield, cutting instructions, sewing instructions, finishing, labeling, technical drawing and packaging.

Two design ideas are worth stressing here. The first is that two different tables coexist in the size chart and they must not be confused: the body measurements of whoever will wear the garment, and the measurements of the finished garment (the so-called points of measure, or POM), which already include the design ease. The second is that it is not enough to name a point of measure ("waist", "chest"): you have to say from where to where it is measured and with what tolerance, because that lack of precision is, according to industry guides, the most common reason a sample doesn't match what later comes out of bulk production.

The same structure, different weight by category

The general structure of the tech pack is the same in every category, but what becomes critical changes. In woven garments (shirts, pants, jackets) the weight is on interfacings and tighter tolerances, because the fabric doesn't "forgive" with stretch. In knits it is the opposite: the material defines almost everything else in the spec sheet, tolerances are wider and the stitch type has to be able to stretch along with the fabric.

In denim, the tech pack becomes the most detailed of all in trims and construction: rivets, type of wash and a double-stitched flat hem seam as the standard. In shirtmaking the focus shifts to collar, cuff and button placket. Tailoring is where there is the most interfacing and internal construction, with a layer specification (fabric, interfacing, horsehair canvas, lining) that doesn't exist in the other categories. And in sportswear the tech pack stops looking only at the appearance of the seam and looks at its physical performance: chafing against the skin, elasticity and, in waterproof garments, heat-sealed seams.

The technical drawing doesn't interpret, it describes

Within the tech pack there is one piece that connects directly with design work: the flat technical drawing (flat sketch), the representation of the garment without stylization or a human body, with front and back views at a minimum. Unlike a fashion sketch, which interprets and communicates an idea, the technical drawing describes: it is dimensioned with the key measurements of the silhouette and accompanied by enlarged construction details of the pocket, collar, cuff or waistband.

That difference is the one you will handle as a designer: the fashion sketch sells the idea, the technical drawing makes it manufacturable. Any ambiguity in that drawing translates directly into an interpretation error in the workshop.

Practical example

For a basic knit t-shirt, the tech pack doesn't just say "chest width 51 cm in size M": it says that this measurement corresponds to the finished garment (not to the body of whoever will wear it), that it tolerates up to ±1.9 cm because of the knit's own stretch, and that the neckband is attached with a coverstitch, not a straight lockstitch, so that it doesn't lose that stretch when pulled.

Common mistakes

Defining the color by a common name ("navy blue") instead of a reference code: Use a standardized color system (for example Pantone) to remove the subjectivity between what the designer imagined and what the workshop understands by that color.

Taking the construction instructions for granted "because it has always been done that way": Specify stitch type, seam allowance and stitches per inch for each area of the garment, without assuming the workshop will interpret it the same way as the designer.

Correcting the design or the technical drawing in a revision and not updating the rest of the tech pack: Version the tech pack (Rev. 01, Rev. 02...) and review every field whenever something changes, not only the one that prompted the revision.

Modeltex tip

Think about the tech pack from the very first sketch, not as a last formality before sending to production: every design decision — an interfacing, a stitch type, a trim chosen over another — has a direct impact on fabric consumption and on the final cost of the garment.

Exercise

Pick a garment you have already designed, even if only as a sketch. Build the header of its tech pack (style code, name, season and base size) and then write, in a single sentence, how you would explain to the workshop one key point of measure of that garment — for example the chest width — leaving no room for interpretation: from where to where it is measured and with what tolerance.

Frequently asked questions

Does the tech pack replace the pattern?

No. The pattern is the physical or digital set of the pieces of the garment; the tech pack is the document that goes with it, with all the information on materials, measurements, sewing, labeling and packaging that the workshop needs to make that garment correctly.

Who builds the tech pack, the designer or the patternmaker?

It depends on how the team is set up, but conceptually it starts with design: the designer defines the idea, the category and the aesthetic priorities, and that information is translated into the technical fields of the tech pack, often together with whoever does the patternmaking.

Does a tech pack work the same for a woven garment as for a knit one?

The general structure of fields is the same, but the weight of each one changes: in knits, for example, tolerances are wider and the stitch type has to go along with the stretch of the fabric.

Summary

The tech pack is the contractual document that translates a design into manufacturing instructions: without it, every decision is left to the workshop's discretion and that creates variation between lots. It organizes the information in blocks — header, size chart, materials, consumption, cutting, sewing, finishing, labeling, technical drawing and packaging — that stay the same in any category, although the weight of each block changes depending on whether it is a woven, knit, denim, shirt, tailored or sportswear garment.

Go back to the full course or ask the Modeltex Lab AI.