How to draw technical flats (flat sketches) for a tech pack

What a technical flat is, what it must show, and a simple way to draw clean front and back flats with call-outs, even if you are not an illustrator.

Updated 1 October 2026 · By Hem Apparel

A technical flat is a black-and-white drawing of a garment laid flat, with no model, shading or mood. Its job is to show shape, seams and details precisely, so that a pattern maker can read it without guessing.

What a flat must show

Front and back views, drawn to realistic proportions.
Seam lines, hems, necklines, pockets, zips and openings.
Stitching: dashed lines where there is topstitching.
Placement of artwork, labels and trims.
Close-ups for details that are too small to read on the main view.

Flat sketch versus a fashion illustration

	Fashion illustration	Technical flat
Purpose	Mood and style	Instructions for making
Style	Expressive, on a figure	Precise, symmetrical, on its own
Detail	Often loose	Every seam and finish
Used by	Designers and buyers	Pattern makers and factories

How to draw one

Start from a template or a trace of a real garment laid flat, so proportions are right.
Draw half of the garment, then mirror it so both sides match.
Use a thicker line for the outline and thinner lines for seams and details.
Show stitching with dashed lines.
Draw the back view and add any inside details, such as lining or facing, if relevant.
Number each detail with a call-out and describe it in the notes.
Keep the sketch in proportion to the measurements in your spec.

Call-outs

Call-outs are numbered arrows that point to a detail and refer to a note, such as '1. 1×1 rib neckband, 2 cm wide' or '2. Double-needle hem, 2.5 cm'. They turn a drawing into instructions.

Common mistakes

Drawing a flat that does not match the spec sheet measurements.
Leaving off the back view.
Forgetting stitch lines and hem depths.
Using a photo or a sketch with shading instead of a flat.
Adding a detail to the sample that is missing from the flat.