Almost every mis-produced sample we've been called in to fix starts the same way: a brand sent a factory a flat sketch and expected tech-pack results. The two documents look similar at a glance. They are not interchangeable, and the gap between them is where sampling delays, wrong trims, and size confusion come from.
What a flat sketch actually is
A flat sketch (or "technical flat") is a clean, proportionate line drawing of a garment, shown front and back, without a body inside it. No shading, no styling, just the construction lines: seams, darts, topstitching, closures, pockets. It answers one question: what does this garment look like, flat?
A good flat sketch is genuinely useful. It's what a designer uses to communicate a concept, what goes into a lookbook or line sheet, and what a factory uses as a starting reference before anything else exists. On its own, though, it doesn't tell anyone how to build the garment; it tells them what the garment should look like once it's built.
What a tech pack actually is
A tech pack is the full production instruction set. It includes the flat sketch, but wraps it in everything a factory needs to cut, sew, grade, and finish the garment without guessing:
- Point-of-measure (POM) sheet: exact measurements at every key point, per size.
- Bill of materials (BOM): every fabric, trim, thread, and hardware, with supplier or reference codes where possible.
- Construction and stitch details: seam types, stitch counts per inch, finishing methods.
- Labels, care instructions, and packaging notes.
- Graded specs across the full size range, so a size Small and a size XL both fit the way they're supposed to.
It answers a different question: exactly how is this garment built, at every size, with zero ambiguity?
Where brands actually get burned
A flat sketch is fine for early concept work, pitching a buyer, or getting a rough sourcing quote. It is not fine as the only document you hand a factory before a bulk order. Without a POM sheet, a factory has to guess your fit intent. Without a BOM, they'll substitute trims. Without graded specs, your Medium might fit true and your Large might not, because nobody defined how the grade rules should scale between them.
The pattern is consistent: the earlier a brand skips the tech pack step to "save time," the more expensive the fix becomes once samples come back wrong, and the more rounds of revision it takes to get a bulk order approved.
Which one do you actually need right now?
If you're still deciding on silhouette, pitching a concept, or sourcing early quotes: a flat sketch, or a small package with a couple of colorways, is usually enough. If you're moving into sampling, grading across sizes, or placing any kind of production order: you need a full tech pack, not a nicer flat sketch.
Most projects that start with "I just need a sketch" end up needing the tech pack within a few weeks anyway, once a factory actually asks for measurements or a BOM. Building it once, properly, is almost always faster than patching a flat sketch into production-readiness under deadline pressure.