Satin, tatami and underlay explained

Every object in Threadsmith has a stitch type and a few numbers that decide how it sews. Good values make the difference between a crisp badge and a puckered, thread-breaking mess. This tutorial walks through each type with the settings that matter.

Running stitch — lines and outlines

A running stitch is a simple line of stitches. Use it for details, outlines, placement lines and travel paths.

Satin — smooth columns and borders

Satin stitches zig-zag across a column. They look shiny because the thread lies in long parallel strands.

• Column width (lines, text, borders): keep satin between about 1 and 8 mm. Narrower looks thin, wider snags.
• Density (spacing): the distance between stitches, typically 0.35–0.45 mm. Smaller numbers = denser.
• Pull compensation: the thread pulls the fabric inwards, so columns come out narrower than drawn. 0.2 mm per side suits woven fabric; use 0.3–0.4 mm on knits (the Fabric setting of the design suggests a value).
• Auto split wide stitches: stitches longer than Max width are broken into shorter ones with staggered penetrations so they do not snag.
• Short stitches on curves: on tight curves every other stitch on the inner edge stops at 60 % of the width, so the inside of the curve does not become a hard knot of thread.
• Satin mode for closed shapes: Fill across the shape (rows across the narrow direction) or Border along the outline (a satin column following the edge — the classic patch border).

Tatami — filling larger areas

Tatami (fill) stitches sew back-and-forth rows at a fixed angle.

• Row spacing 0.4 mm is a dense, solid fill; 0.5–0.6 mm is lighter.
• Stitch length 3–4 mm.
• Stagger pattern shifts the needle points of neighbouring rows (1/3 by default) so no visible lines appear in the fill. 2/5 gives an almost random look.
• Graded density changes the row spacing gradually across the shape — nice for soft fades or light backgrounds.

Threadsmith splits complex shapes (letters, U-shapes, holes) into blocks that can each be sewn without leaving the shape, and orders the blocks nearest-first.

Contour fill and motif runs

• Contour fill sews rings that follow the outline inwards — great for stars, hearts and organic shapes.
• Motif run repeats a small pattern along a line: wave, zig-zag, scallop, diamond chain or E-stitch (blanket stitch for appliqué edges).

Underlay — the foundation

Underlay is a sparse layer sewn before the visible stitches. It stabilises the fabric and lifts the top stitches.

Threadsmith picks sensible underlay automatically when you switch stitch type; you can change it per object in Properties → Stitches → Underlay, or for several objects at once with Stitch → Underlay.

Check the density

Press 3 for the Density view. Every stitch deposits thread into 1 mm cells; the colours show how many layers of thread end up there.

• Blue/green: normal coverage (one layer of top stitching ≈ 1).
• Yellow: getting thick (underlay + top + overlap).
• Red and circled: above the too-dense limit (2.6 layers by default, changeable in the design properties). Expect thread breaks, needle deflection or a stiff, bullet-proof patch there.

Typical fixes: reduce satin density (0.4 → 0.45 mm), remove one underlay layer, avoid stacking a fill under a satin border, or let shapes overlap by only 0.5–1 mm. The Stats tab lists the exact problem areas.

Quick reference