Stitch files vs object files: what is the difference and why it matters

The short version

A stitch file is the output: a list of needle positions, in order, with commands for color changes, trims, jumps and stops. It is what your machine reads. An object file is the source: shapes (objects) with properties such as stitch type, angle, density, underlay and pull compensation. Digitizing software turns objects into stitches every time you change a property, then exports a stitch file for the machine.

The analogy that works best is a recipe versus a baked cake. With the recipe you can make a bigger cake that bakes properly. With the cake, you can only slice it, decorate it or squash it.

What exactly is inside a stitch file?

Strip a stitch file down and you find a header (design name, sometimes dimensions, color list and hoop information depending on the format) followed by a long stream of records. In most formats each record is a relative move: "go 2.4 mm right and 0.3 mm down, then drop the needle." Commands are mixed into the stream: jump (move without stitching), trim, color change or stop, and end.

Because the moves are relative, the file has no idea what shape it is drawing. A satin column is just a zigzag of points. A fill is rows of short stitches. Underlay is just more stitches that happen to come first. That is why you cannot ask a stitch file to "make this satin a bit narrower": there is no satin object to adjust, only hundreds of separate points.

Some formats hold more than others. DST, the commercial standard, stores stitches and color-change commands but no actual thread colors, so a DST opens in software with arbitrary colors. PES and VP3 store thread color information that brand software and machines display. None of these store the underlay or density settings the digitizer used, even though the stitches those settings produced are all there.

What is inside an object file?

An object file stores the design the way the digitizer built it. A typical object holds:

• The outline or centerline of the shape (vector nodes and curves).
• The stitch type: run, satin, fill, motif, and so on (see stitch types).
• Stitch angle or angle lines for satins and fills.
• Density (spacing), stitch length, fill pattern.
• Underlay type and its own spacing and inset.
• Pull compensation, often per side.
• Entry and exit points, tie-ins and tie-offs, trim settings.
• For lettering: the font, the text, size, spacing and baseline, all still editable.

When you change any of these, the software regenerates the stitches for that object. Scale a satin column up 50 percent and the software keeps the stitch spacing the same, widens the column, and if the column gets too wide it can switch to a split satin or warn you. This is what makes big changes clean in an object file and messy in a stitch file.

How to tell which kind of file you have

1. Look at the extension. If it is a format your machine reads (PES, DST, JEF, EXP, VP3, XXX), it is a stitch file. If it is a software working format (EMB, ART, PXF, BE, JEF+), it is an object file. The file formats guide lists which is which.
2. Open it in software and click a shape. In an object file, clicking a letter or fill selects that object and shows its properties: stitch type, density, underlay. In a stitch file you will usually select a whole color block, or a group of stitches the program has guessed at, with only basic properties available.
3. Try to edit the text. If you can retype a name and the letters regenerate, you have lettering objects. If the name is a block of stitches you can only delete, it is stitch data.

What you can safely do with a stitch file

Stitch files are not useless for editing. Plenty of jobs never need the object file:

• Recolor. Changing the thread assigned to each color stop is harmless. See thread color conversion for matching across brands.
• Combine colors or reorder stops, when the layering allows it. Combining two adjacent stops of the same color saves a thread change.
• Rotate, mirror and move. Rotation is safe in any increment; the stitches keep their length and spacing. Mirroring is safe as long as you remember that the fill angle mirrors too.
• Merge designs and add lettering. Utilities place stitch files next to each other or add a name from built-in fonts. The fonts are objects inside the program even if the design is not.
• Delete parts. Removing a whole color block or a selected group of stitches works well, but watch for underlay or travel runs from neighboring objects that were hidden under what you deleted.
• Resize modestly. About 10 to 20 percent, as explained in resizing designs.

What stitch files cannot do well

Large resizes

Scale a stitch file up 40 percent and every stitch gets 40 percent longer while the spacing between rows also grows. Satins become wide and loose, fills open up and show fabric, and long stitches start to snag. Scale down 40 percent and the opposite happens: rows crowd together, density climbs, and the design turns stiff and may break needles. Some programs offer "stitch processing" that recalculates density on a resize, which helps for fills but cannot rebuild underlay or recalculate pull compensation properly.

Fabric changes

A design digitized for twill has compensation and underlay chosen for twill. Moving it to a stretchy performance knit or a deep-pile towel calls for more underlay, different compensation and often a lighter density. In an object file that is a few setting changes. In a stitch file it is not possible, so your options are stabilizer and topper choices (see the stabilizer chart) or a re-digitize.

Text changes

A name or slogan saved as stitches cannot be retyped. You delete it and add new lettering, which will be in a different font unless your software has a matching one.

Why you should keep both

If you digitize, or pay someone to digitize for you, the object file is the asset. Stitch files can always be exported from it in any format, at any size, tuned for any fabric. Lose the object file and every future change becomes a compromise or a fresh job.

• Save the object file in your software's native format first, then export stitch files.
• Name exports so you can tell them apart: design name, size, fabric, and version (for example, logo-left-chest-90mm-pique-v2.dst).
• When ordering custom digitizing, ask whether the object file is included and in which program's format. A Wilcom EMB is no use if you run different software.
• Back up both, along with the original artwork.

Converting stitch files back to objects

Several programs can import a stitch file and attempt to recognize objects, sometimes called stitch-to-object conversion or recognition. Results depend heavily on how clean the stitches are. Simple satins and fills often come back reasonably well; underlay, overlapping areas and complex lettering usually come back as plain stitch blocks or with guessed settings. Treat the output as a starting point that needs checking object by object, not as a recovered original. For a logo that will be stitched often, re-digitizing from clean artwork is usually faster in the end. See what digitizing involves and the honest limits of auto-digitizing.