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Apparel CAD • 7 min read • Updated Oct 2026
ASTM D6673 / AAMA DXF Layers Explained for CLO3D & Gerber
How modern 3D fashion simulators and industrial cutting plotters interpret multi-layered CAD vector patterns.
Why Standard Architectural DXF Fails in Fashion
AutoCAD DXF was designed for buildings and mechanical gears. In architectural CAD, lines are simply lines.
In apparel manufacturing, an automated cutting knife must know the exact difference between the outer boundary to slice with a laser, an internal stitch line, a balance notch to nick by 5mm, and a straight grainline indicating fabric warp orientation.
To standardize this across manufacturers, the American Society for Testing and Materials established the ASTM D6673 / AAMA 292 standard.
| Layer # | Standard Name | Description in sloper.fit | Action in CLO3D / Gerber |
|---|---|---|---|
| Layer 1 | Boundary / Cutline | Closed perimeter including seam allowances | Knife Cut / 2D Pattern Outer Boundary |
| Layer 2 | Internal Seamline | True sewing line (10mm offset) | Sewing Edge / Folding Line |
| Layer 4 | Notches | Slit notches at scye & waist balance points | Notch Markers on Fabric Edge |
| Layer 7 | Grainline | Vector arrow along warp direction | Fabric Texture Weft/Warp Orientation |
| Layer 11 | Internal Darts | Dart legs and apex points | Dart Folding & Stitch Simulation |
How to Import sloper.fit DXF into CLO3D
- Download the ASTM D6673 DXF file from any pattern page on sloper.fit.
- In CLO3D, click
File > Import > DXF. - In the DXF Import options dialog, select "AAMA" as the DXF Format and "Millimeter (mm)" as the Scale.
- Click OK. Your pattern pieces will instantly appear in the 2D window with correct grainlines, sewing lines, and boundary shapes!