Tech Pack vs Sewing Pattern: What's the Difference?
While both documents are essential for clothing production, a tech pack is a comprehensive specification blueprint while a sewing pattern is the physical or CAD cutting template.
General industry knowledge • Reviewed by Fenalt editorial team
A tech pack answers: “What materials, measurements, colours, and construction rules build this garment?” A sewing pattern answers: “What exact 2D panel shapes must be cut from fabric to sew it?”
Understanding the distinction between tech packs and sewing patterns prevents costly miscommunications when commissioning clothing production. Brands supply tech packs as master instructions; pattern makers translate those specs into physical cutting templates.
Detailed Matrix
8-Point Comparison: Tech Pack vs Sewing Pattern
| Criteria | Tech Pack | Sewing Pattern |
|---|---|---|
| Primary Format | Multi-page specification document (PDF or Excel spreadsheet) with vector drawings and tables. | Digital CAD vector cutting files (DXF/AAMA) or physical paper pattern piece templates. |
| Primary Purpose | Communicates complete design intent, fabric specs, BOM, tolerances, and quality guidelines to suppliers. | Serves as the physical layout template used directly by cutting technicians to cut fabric layers. |
| Target Audience | Sourcing managers, fabric suppliers, merchandisers, pattern makers, and QC auditors. | CAD pattern engineers, cutting table operators, and sample room machinists. |
| Key Contents | BOM, Pantone colorways, stitch callouts, print placement coordinates, POM spec tables, packaging rules. | 2D 1:1 scale panel outlines (front, back, sleeve, hood, pocket) with seam allowances, grainlines, and notch marks. |
| Created By | Fashion designers or technical designers during early product development. | Professional CAD pattern makers or sample machinists prior to sample sewing. |
| Workflow Sequence | Created first - acts as the master reference from which sewing patterns are drafted. | Drafted second - uses tech pack POM tables and flat sketches as mathematical targets. |
| Standard File Extensions | .PDF, .XLSX, .AI, .PNG | .DXF (AAMA/ASTM), .PLT, .RUL, .MDL |
| Ownership & Rights | Created and owned directly by the brand as intellectual property. | Drafted by the factory or pattern studio; brand must explicitly contract for CAD file ownership. |
Production Synergy
How Tech Packs & Patterns Work Together
1. Brand Creates & Issues Master Tech Pack
The brand compiles design vector sketches, POM measurement specs, and BOM fabric callouts into a finalized tech pack PDF.
2. Factory Pattern Maker Drafts CAD Master Pattern
Using specialised CAD software (Gerber, Lectra, Optitex), the pattern maker converts flat tech pack specs into a 1:1 scale 2D digital master pattern.
3. Sample Machinist Sews Fit Prototype
Fabric is cut using the CAD pattern pieces and assembled to test pattern line accuracy against tech pack POM dimensions.
4. CAD Pattern Is Graded for Bulk Production
Once fit is signed off, the pattern maker applies CAD size grading across the full size run (XS–3XL) and generates optimized cutting markers.
Questions
Frequently Asked Questions
Can a clothing factory make a sewing pattern if I only provide a tech pack?
Yes! Professional apparel manufacturers employ technical CAD pattern makers who translate tech pack POM measurement tables, flat vector drawings, and construction notes into 1:1 digital sewing patterns.
Can I start sampling if I only have a sewing pattern but no tech pack?
No. A sewing pattern only provides fabric cutting shapes - it does not specify fabric composition, GSM weight, thread types, Pantone colours, label placement, stitch callouts, or quality control tolerances. Both are required for accurate manufacturing.
Do brands own the CAD sewing patterns created by a factory?
Brands own the digital pattern files if pattern development fees were paid as part of the sampling agreement. Brands should explicitly confirm in their contract that exported DXF/AAMA CAD pattern files will be delivered upon request.
What is DXF/AAMA format in CAD pattern making?
DXF (Drawing Exchange Format) with AAMA/ASTM extensions is the universal open standard for digital garment patterns, allowing patterns created in one CAD system (such as Lectra or Gerber) to be opened in any other system worldwide.
What is seam allowance in pattern making?
Seam allowance is the extra width of fabric added outside the actual seamline (typically 0.6cm to 1.2cm) to allow panels to be sewn together securely without altering final garment dimensions specified in the tech pack.
How does Fenalt handle pattern development?
Fenalt's Dhaka technical team converts brand tech packs into precise digital CAD patterns, conducts fit sampling, and manages CAD size grading for bulk production.
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