Features — StitchFast AI Embroidery Digitizer | AI Analysis, Fill Stitch, Satin, 7 Formats

AI Feature 01

AI Design Analysis

When you upload an image, Claude Vision AI analyses it the way an expert digitizer would — identifying distinct regions, suggesting the best stitch type for each area, and setting parameters automatically.

What the AI decides for you: stitch type per region (fill, satin, or running), optimal stitch angles for each colour block, recommended thread colours, hoop size selection, and pull compensation values. All of this feeds into the digitizer before you hit a single button. You can override any setting manually.

Claude Vision Per-region analysis Auto-settings

AI Analysis Output

"Multi-colour logo with 4 distinct regions. Main body suitable for tatami fill at 0°. Thin border elements need satin stitch."

Red bodyFILL 0°

Blue accentFILL 45°

Black outlineSATIN

Green detailRUNNING

130×180

Hoop

0.3mm

Pull Comp

4

Colours

Feature 02

Tatami Fill Stitch

Large areas are filled with rows of parallel stitches using an offset tatami pattern. Each row is staggered by 40% of the stitch length to prevent visible ridges and give smooth, professional coverage.

Configurable density from 2 to 8 lines per millimetre. Lower density (2–3) is faster to sew and works well on caps and thick fabrics. Higher density (5–8) gives full coverage on thin fabrics and small details. The default of 4 lines/mm is a solid all-rounder.

Even-odd scanline fill handles complex shapes correctly — the letter O fills the ring and skips the centre. Shapes with multiple holes are traced with marching squares and filled using even-odd rule across all contours in a single pass.

2–8 lines/mm 40% row offset Even-odd fill Hole detection

TATAMI FILL — OFFSET ROW PATTERN

Feature 03

Auto Satin Columns

Narrow regions under 3mm wide are automatically switched to satin stitch. Each stitch spans the full width of the column, zigzagging side to side for a smooth, raised finish — exactly how professional digitizers handle borders, text strokes, and thin shapes.

Width detection samples 12 cross-sections along each region to measure the average width. Anything under 3mm triggers satin mode. This prevents the ugly birdnesting you get when fill stitch is forced into a space too narrow for parallel rows.

Density matches fill settings — the same lines-per-mm value controls satin spacing, so your satin and fill regions look visually consistent.

<3mm auto-detect 12-point sampling Full-width spans

SATIN COLUMN — FULL-WIDTH ZIGZAG

AI Feature 04

Pull Compensation

Thread tension pulls fabric inward during stitching, making fill areas narrower than designed. Pull compensation automatically overshoots each edge by a configurable amount — so the finished result matches your original design.

Adjustable from 0 to 1mm in 0.05mm increments. The default is 0.3mm, which works well for most woven fabrics. Stretchy materials like jersey or fleece benefit from 0.4–0.6mm. The AI analyses your design and suggests a starting value.

Most cheap digitizers skip this entirely. The result is fill areas that look thinner than the original artwork, borders that don't meet properly, and gaps between colour blocks. It's one of the biggest quality differences between professional and amateur digitizing.

0–1mm range 0.05mm steps AI-suggested Per-edge overshoot

EDGE OVERSHOOT COMPENSATES FOR FABRIC PULL

Feature 05

Underlay Stitching

A foundation layer stitched before the main fill. Underlay locks the fabric down, prevents puckering, and gives the top stitches something to grip. Without it, fill areas can sink into stretchy fabrics or shift on loose weaves.

Three modes: None (no underlay — for pre-stabilised fabric), Light (sparse perpendicular lines at 1 line/mm, 8mm stitch length — good for stable wovens), and Full (dense cross-hatch at 2 lines/mm, 5mm stitch length — recommended for knits, fleece, and large fill areas).

Underlay runs perpendicular to the top fill angle. If your fill runs at 0° (horizontal), underlay runs at 90° (vertical). This cross-direction layering is what prevents the top stitches from sinking.

None Light (1 L/mm) Full (2 L/mm) Cross-direction

None

Pre-stabilised

Light

Woven fabrics

Full

Knits & stretch

90°

Cross-direction

Feature 06

Madeira Thread Matching

Your image colours are reduced using median-cut quantization with K-means refinement, then each colour is matched to the nearest real thread in a 32-colour Madeira Rayon palette using perceptual colour distance.

Configurable from 2 to 16 colours. The AI suggests the optimal count based on your image. Duplicate thread matches are removed, so the final palette only includes threads that are genuinely different — no wasted colour changes.

Every thread includes its Madeira catalogue number so you know exactly which spool to buy or load. The full thread list appears in the Threads tab after digitizing.

32-colour palette Madeira Rayon codes 2–16 colours K-means refined

32 MADEIRA RAYON THREADS — CATALOGUE NUMBERS INCLUDED

Feature 07

Real-Time Stitch Simulation

Watch your design stitch out on screen before downloading. The simulator renders every stitch in sequence, colour by colour, at adjustable speed — so you can see exactly how the machine will sew it.

Catches problems before they cost thread. Spot gaps between fill areas, check colour ordering, verify outlines land on top of fills. Pause, reset, and adjust speed from 1x to 100x. The preview tab shows the full static render; the simulate tab plays it back live.

Hoop guide overlay shows your selected hoop size with a grid, so you can see exactly where the design sits in the frame.

1x–100x speed Play / Pause / Reset Hoop grid overlay Per-colour playback

SIMULATING...

▶ PLAY

↺ RESET

Feature 08

7 Output Formats

Proper binary embroidery files generated server-side using pyembroidery. Not renamed ZIPs. Not SVG paths in a wrapper. Real stitch coordinates, jump commands, trim commands, and colour changes — ready to load into your machine.

DST (Tajima) — the universal format, works on virtually every machine made in the last 30 years. PES (Brother/Babylock) — includes embedded RGB thread colours. JEF (Janome/Elna) — Janome's native format with colour data. EXP (Melco) — for Melco commercial machines.

VP3 (Husqvarna/Viking), HUS (Husqvarna), and XXX (Singer) round out the set. All formats enforce a 7mm max stitch length, include trim commands before jumps, and handle colour changes correctly.

.DST

Tajima

.PES

Brother

.JEF

Janome

.EXP

Melco

.VP3

Husqvarna

.HUS

Husqvarna

.XXX

Singer

Feature 09

Marching Squares Contour Tracing

Every colour region is traced using marching squares with sub-pixel precision — not simple edge detection. The algorithm finds both outer boundaries and inner holes (the inside of an O, a ring shape, a frame with cutouts) in a single pass.

Contours are then simplified using the Ramer-Douglas-Peucker algorithm to remove unnecessary points without losing shape accuracy. Then Chaikin subdivision smoothing (2 iterations) rounds off jagged pixel steps into clean curves.

Running stitch outlines are generated along the smoothed contours to give crisp edges around each filled region.

Marching squares Hole detection RDP simplification Chaikin smoothing

OUTER + HOLE CONTOURS TRACED IN ONE PASS

Feature 10

Full Control When You Want It

The AI sets sensible defaults, but every parameter is exposed. Adjust anything before digitizing — hoop size, colour count, fill density, stitch length, underlay type, and pull compensation. Preview updates instantly.

Hoop sizes: 100×100mm, 130×180mm, 200×200mm, 200×300mm, 360×360mm. Colours: 2–16 threads. Fill density: 2–8 lines/mm. Stitch length: 1.5–5mm. Underlay: None, Light, Full. Pull compensation: 0–1mm in 0.05mm steps.

Designs over 80,000 stitches show a warning suggesting you reduce density or colours to keep sew time manageable.

5

Hoop sizes

2–16

Colours

2–8

Density L/mm

1.5–5

Stitch mm

3

Underlay modes

0–1

Pull comp mm

Comparison

StitchFast vs Everything Else

How StitchFast compares to manual digitizers, desktop software, and other online tools.

Feature	StitchFast	Manual Digitizer	Free Online Tools
Turnaround	Instant	24–48 hours	Instant
Cost per design	From £3.50	£5–£15+	Free
AI analysis	Claude Vision	No	No
Proper fill stitch	Tatami	Yes	Auto-traced lines
Pull compensation	Automatic	Manual	No
Underlay	3 modes	Manual	No
Thread codes	Madeira	Sometimes	No
Stitch simulation	Live	Static image	No
Output formats	7 formats	1–2 formats	1–2 formats
Hole detection	Marching squares	Manual	No
Trim commands	Automatic	Yes	Often missing

Not just another auto-trace tool