Fill (Tatami) — Angle, density and fill patterns

What is the Fill tool for?

A closed region filled edge-to-edge with rows of straight stitches — the standard way to cover a large area. Draw a closed shape (or use one from Shapes) and pick Fill from the rail.

What does increasing or decreasing Density actually look like?

Density is the gap between one row of stitching and the next. Turn it down (tighter spacing, sometimes shown as a smaller millimeter value) and rows pack closer together — fuller, more opaque coverage, more thread used, and on lightweight or stretchy fabric, more stiffening. Turn it up (wider spacing) and the fill gets faster and lighter, but past a certain point the base fabric starts to show through between rows. There’s no universal “correct” value — it’s a trade-off you make per fabric and per design, which is why it’s an editable slider rather than a fixed constant.

What’s the “Satin edge” toggle I see on some Fill objects?

A thin satin band stitched along the fill’s outline, in the same thread as the fill itself — it crisps up the edge and stops the fill’s raw border from fraying, without needing a separate Border object. Toggle it on and an Edge width slider appears to set how wide that band is (typically kept quite thin, around 1 mm). This is different from adding an explicit Border — Satin edge is a lightweight, same-color finish built into the Fill object itself.

What does “Angle” do, and what if my shape curves?

One fixed direction for every row in the fill. For a shape that curves — a banana, a wavy ribbon — a single angle can look wrong on part of the shape; draw a flow line instead, right below the Angle slider, to have the rows follow the curve rather than a straight compass direction.

What do density and stitch length control?

Density (row spacing) sets how close together the parallel rows of stitching sit — tighter spacing gives fuller coverage but uses more thread and can stiffen fabric more. Stitch length sets the spacing of the needle penetrations within each row.

The two are less interchangeable than they look. Coverage depends on density alone: the thread laid down per square millimeter is exactly one divided by the row spacing, and stitch length does not enter into it. What stitch length changes is how many needle penetrations that same thread costs — a 4 mm row stitch puts down as much thread as a 2.5 mm one with about a third fewer holes in the fabric, which on knits usually looks better rather than worse. So if a fill looks thin, tighten the density; lengthening or shortening the stitch will not close it.

Does a fill have pull compensation, like a satin column?

Yes, since 1.0 (4). Stitching pulls the fabric in along the direction of the stitches, so a tatami fill comes out a hair narrower than drawn along its rows. Pull compensation in the fill’s settings sews every row that much past the outline at both ends — 0.2 mm by default, the same as a satin column — the way Hatch does it. Raise it on stretchy fabric or where a fill meets a border and leaves a thread of fabric showing; the Jersey and Fleece fabric settings add their own share on top. It works along the rows only: across them the rows sit where they sit. Guided fills reach past the outline along their curved rows the same way; Contour and Sashiko have no row ends and are not affected.

Why does my fabric still show through — and what should density be?

On jersey with ordinary 40wt thread, coverage closes at a row spacing near 0.20 mm, and the change is abrupt — 0.22 mm can still speckle. The factory Tatami presets start at 0.25 mm, which is the right value for stable woven cloth; on Knit/Jersey the app tightens it for you. That is why the fabric setting matters so much.

Does thread weight change the density I need?

Yes, and the app cannot know which spool is on your machine — so this one is yours to set. The number on the cone (40, 60, …) is a fineness figure, not a length: higher means finer. It describes mass per unit length, and a thread’s width — which is what actually covers fabric — grows with the square root of that. A 60wt therefore lies down roughly 80 % as wide as a 40wt, and wants roughly 80 % of the row spacing to cover the same way.

Starting from 0.20 mm for 40wt, that gives a rule of thumb. Treat it as a starting point and sew a test swatch with your own thread:

Thread	Row spacing for comparable coverage
30wt (thicker)	~0.23 mm
40wt	0.20 mm
50wt	~0.18 mm
60wt	~0.16 mm

The density slider goes down to 0.15 mm, so there is room for finer thread. The automatic fabric compensation only tightens so far by itself; a value you set below that is always kept as you set it. Do remember the rest of the setup: finer thread usually wants a finer needle, and the same area needs more metres of it.

Two things follow. If your fill looks open on a T-shirt, check that the design’s fabric is set to Knit/Jersey rather than Woven — the compensation only happens when the app knows what it is sewing onto. And an object keeps the density it was created with. If an older design looks thin, set its density explicitly — or copy the style from a fresh object.

And the open end of the slider — what are 2 or 3 mm good for?

Rows this far apart no longer cover, and for two jobs that is the point.

One is the knockdown: a coarse grid sewn before the design itself, flattening the pile of towelling, fleece or plush. Without it the motif sinks between the loops and comes out fuzzy. The Knockdown stitch in the fill list is set up for it: 2 mm row spacing, 0° angle, no underlay, no pull compensation. The angle is 0° because ordinary fills sit at 45° — the design then crosses the knockdown instead of sinking into its gaps.

How to use it:

Finish the design and select it.
Contour, Around all, the distance you like, corners rounded, Stitch Knockdown. The area follows the design’s shape and is inserted before it, so it sews first.

A rectangle works too: pick the Knockdown stitch, drop a rectangle over the design with Shapes and move it to the bottom of Layers.

On colour: in the colour of the first design object the two merge into one colour block and you save a thread change. In a fabric tone the margin sticking out past the design disappears — at the cost of one re-thread.

The other job is the open fill as an effect: between 1.5 and 2.5 mm the fabric colour mixes visibly into the shade instead of being covered.

The slider runs to 3.0 mm. Two things step back up there. The automatic fabric compensation leaves a grid this open alone — otherwise towelling, of all fabrics, would have tightened the knockdown right back up. And the check stops calling a fill open once something sews over it: then it is a foundation, not the face.

What are the six fill patterns, and how do I choose?

Opened from the pattern grid in the Fill inspector:

Diagonal — the default weave, an even zigzag look
Brick — a calmer, offset-row look, like brickwork
Scatter — randomizes the row offset to hide any visible seam lines
Wave — the rows themselves undulate
Chevron — a zig-zagging texture phase
Ring — rings that follow the shape’s own outline inward rather than a straight scanline direction, useful for organic shapes where you want the texture to read as “wrapped around” the form. Ring is a solid fill of true parallel offsets, not a decorative curve family: coverage stays even across the shape, and holes are respected. With Ring the stitch length is an upper limit: where a ring bends tightly the stitches get shorter, so they follow the ring instead of cutting across it. On straight stretches and wide bends the length you set stays; toward the middle of a round shape the stitches shorten by themselves

Can I get a pattern into the surface without a second colour?

Yes — that’s Carving, a block further down this same inspector. You draw a line and the fill’s own needle holes line up on it, so a groove appears in the stitched surface for almost no extra stitches. Ten patterns come built in.

Are Guided fill and Sashiko in this picker?

No — both are separate, deliberately distinct paths. Guided fill is entered via the object’s flow-line tooling described above; Sashiko is its own motif-lattice mode reached from the object’s action grid, not from this pattern list, since it replaces the whole fill rather than just choosing a texture for it.

The same goes for the satin area: it takes over the whole cover, so it is a button under this picker (Fill with satin (turning)) rather than a seventh pattern. Your row texture is remembered and comes back when you leave it.

Do fills have underlay too, and what do the firmness steps mean?

Yes — and on knits it’s the difference between a clean fill and one where the fabric shows through between rows. The Fill inspector has its own Underlay toggle with the same Auto / Light / Standard / Firm / Custom ladder as Satin, but the passes underneath are different:

Light — edge run only, along the inset contour. Right for stable woven fabric and small shapes.
Standard — edge run plus one coarse cross pass under the cover stitching.
Firm — edge run plus a full diagonal lattice.
Auto — follows the design’s Target fabric: knits and pile get the lattice automatically.
Custom — pick the passes yourself. Like satin, it opens pre-filled with whatever the ladder was already building for that fill.

Two sliders sit below: Underlay spacing (1.2–3.0 mm, how far apart the underlay rows sit) and Edge inset (0.2–1.0 mm, how far inside the outline the edge run stays so it doesn’t peek out from under the cover).

Can I choose where a fill starts and ends?

Select the fill: the green ring on the canvas is the start, the red ring the end. When both sit on one spot — the rows end where they began — the red ring is drawn around the green one; grab its band. Drag either onto the outline and it is kept with the object; Reset ends in the inspector lets the app choose again. The start always holds. The end is honoured where the shape gives the rows a choice — a star, a notched or holed shape, anything that sews in several bands. On a plain shape without notches or holes the rows run back and forth in one sweep and end on the side opposite the start; the inspector tells you when the red ring could not be followed, and moving the start to the far side is the way to get the end you want.

What is “Remove Overlaps” and does it belong here?

It’s a separate action (in the object action grid, not the Fill inspector) that hides fill stitches which end up hidden underneath later objects — see Cut, combine & convert.