Fractal Machine Embroidery

Avoiding Embroidery Pitfalls – a Hands-On Tutorial by Gryphern


When you embroider a fractal you will be pushing your digitizing software to its limits, and possibly your embroidery machine will be reaching its limits as well.

This article discusses how to avoid hours of computing time and days of going back and fixing problems. I'm using the Embird software with the Studio add-on.

Stitch Size

There is a limit to how short a stitch can be.

This design will not come out looking as it does on the computer.

This is especially important if you are making designs to sell or distribute. My Husqvarna machine can make tiny stitches half a millimeter long, my older Singer machine tries, fails, and ends up messing up the design.

The lesson being “not all machines are created equal.” When producing very short stitch designs for personal use, test a portion of a complicated design before you spend many hours creating the whole thing. Recognize that machine embroidery won't produce near microscopic iterations within a fractal. Make details, but if they're less than a millimeter long, test stitch them! Compare the insanely small stitches to the millimeter scale at the top.

Digitizing Fractal Images

Understanding your Digitizer

If you are working in a graphics editing program and plan to convert a fractal image to stitches, you have to draw your pictures like your digitizing software “thinks.” And that software is trying to think in neat little paths that don't cross over each other.

Avoiding Loops

Two variants of the fractal dragon curve

The image on the left is a is a special form of hell for your embroidery digitizer. But the image on the right is a very happy-quick job for the digitizer. Why is it that the right image is so terrible? Loops. Closed loops, with lots of branches. Embroidery digitizers just don't know anything about the dragon curve fractal, so they don't know which branch to follow when interpreting the source image. And a brief foray into graph theory teaches us that loops and branches are hella complicated to find the best path through.

So, break up such images in ways that minimize loops, try to obtain smaller groups of loops, or manually create stitches in the right order and direction. Digitize each portion of your image, then combine the portions to create the finished embroidery.

Devide and Conquer

If a fractal is made of simple repeating sub-units, design one of these units manually, then rotate and paste them into the correct stitching order. This is what I did for high accuracy on my 6th-iteration Cesaro fractal, and have done for looping overlapping designs that would otherwise take two hours for the digitizer to plan a path through and another two hours to regenerate the stitches when it saves to disk.

You probably will do a better job than the automatic digitizing software if you plan a path by hand. If you have an incredibly complex design, do your software a favor and save different colors and parts of the design as different embroidery files.

You can stitch several files in a row to create a single design. When I exceed 50,000 stitches my software is more likely to hiccup and incorrectly save complex designs. I've also found that - yes - it is possible to exceed the memory space on the little cards used for mid-level embroidery systems.

Jump Stitches

When the embroidery machine goes between two areas of a design, it leaves a trailing thread called a jump stitch or jump thread. The expensive machines will cut these for you, as long as they are of a certain minimum length. The mid-level and lower end consumer embroidery machines will not cut these.

This means that if you have lots of tiny jump stitches between design parts you're going to have a lot of work ahead of you. This is not a concern for space filling curves and other linear fractals, but it certainly makes a Haferman Carpet a pain in the ass.

Fractal Lace Embroidery

Freestanding Lace Design

Sierpinski drink coaster made of freestanding lace

Freestanding lace or FSL, is when a design is embroidered onto a wash-away / heat-away material. The material is removed after embroidery finishes, leaving a beautiful lace design.

FSL designs are made of satin stitches ontop of underlay stitches. The underlay stitches are straight stitches that are sewn first through the center and edges of where the satin stitch will lie. The lines underneath keep the satin stitches from unraveling.

Creating a Mesh

Unless you have a very rigid structure, such as triangles, the finished FSL will sag and droop, so you need to design a mesh behind the open spaces.

Either embroider onto tulle fabric (bridal veil fabric) or sew a mesh using thread. Background meshes are usually fill stitches at very low density settings, don't manually create a grid, that would take an hour.

You can make a mesh from a straight fill by superimposing it with a copy rotated by 90 degrees. To give the mesh a lacy look, you can stitch motifs (repeating stitch patterns) over the mesh.

When stitching meshes, use the same thread in the bobbin thread as you use for the top thread. Using the same thread in both the bobbin and the spool will prevent thread tension issues and create a mesh that looks uniform. For fills and the rest feel free to use a different bobbin thread than your spool thread.

Fractal Lace Origami

using zigzag stitch to join the parts

The biggest annoyance when designing FSL is that the embroidery machine may not overlap stitches where it ought to, leaving gaps between parts of the design and ruining the structural integrity of the lace. You want big overlaps when designing to make sure everything is stitched together and you don't end up with side by side parts.

Free standing lace can be folded and stitched together - a sort of lace origami. To join lace sections use a zigzag stitch of the same color as the edges of the lace. A dense zigzag will completely hide the gap between the two lace pieces. A loose zigzag will allow the pieces to fold exactly where they meet.

Threads

Variegated Threads

Cesaro Fractal using a variegated thread

Variegated threads can add shifting color to your design, and add color dimension to a space filling curve, but it is incredibly difficult to precisely match up the the color changes with parts of your object.

The best you can do is approximate, as in this Cesaro Fractal, where I approximated the length of each colored segment to the length of line in each repeating unit.

Metallic Threads

Metallic threads will do the following things: Heat up the needle due to friction, then melt. Tangle on their way off the spool, then tear. Run metallic threads on very low thread tension, slow you machine down, and guide the thread as it comes off the spool. Thread nets, an accessory for machine embroidery, are not enough to stop knotting in extremely twisty metallic threads. If you have a very dense design, pause the machine now and then to let the needle cool.

Source Designs

If you don't want to design a fractal yourself – for example by deforming a triangle into a Koch snowflake – you can download or generate fractal images to work from.

Go to Wikipedia or Wolfram Mathworld and search for a fractal you like. You can then use WolframAlpha to generate this fractal, at the number of iterations you like, and download it as a high resolution PDF.

The images are crisp and large, making small details easily visible. For a geometrically inaccurate snowflake, look at the pentaflake. Then, have a look at the hexaflake, which is much harder to digitize but gives a gorgeous result.

Web Links

Resources

Designs

Howtos

howto/fractal_machine_embroidery.txt · Last modified: 2009/10/17 13:42 by magisterludi
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