Article from Issue 272/2023

With the demise of Twitter API access to the beautiful open source client, Harpy, Graham has spent the month on, hoping Harpy's developer brings their skills to the Fediverse.

Sewing pattern designer


It might initially appear that the worlds of clothes and computers have very little in common. But it doesn't take much investigation to realize almost the opposite is true. Sewing, knitting, and crochet are all popular pastimes, regardless of your background, and in many ways the dextrous sequence of patterns they require is analogous to programming. This was even true over a century before the first computers, in the 1820s, when Jacquard's loom wove silk patterns at an industrial scale using cards with human-programmed punched holes to encode and reproduce a pattern. Since then, computers and clothing have had a long history together, and it's now time for open source to start influencing designs too.

This is what Seamly2D does, making fashion and clothing design accessible to anyone with a computer. Seamly2D is to clothing design what FreeCAD is to mechanical engineers, and like FreeCAD, Seamly2D is a desktop application using the Qt GUI framework. It's also a project that has recently won a place in GitHub's Accelerator program, which offers $20,000 and 10 weeks of guidance for each project, plus workshops "with an end goal of building durable streams of funding for their work." Seamly2D describes itself as a "parametric CAD for engineering documents," which sounds complicated, but those engineering documents are clothing designs and they need to be parametric to fit the infinitely variable human form. This doesn't mean that using Seamly2D is easy. It has a learning curve closer to FreeCAD than Figma, but it doesn't require traditional programming skills. Designs are instead crafted from a familiar palette of tools and functions from three different modes of operation: Draft, Piece, and Layout.

The Draft mode is where designers will spend most of their time. It's this mode that has the most icons in the tools palette on the left, and the tools range from the ability to create points and lines at fixed and variable angles, with variable lengths, to curves and arcs with similar properties and simple operations for duplicating, moving, and mirroring groups of points already created. This is the software equivalent to drawing on plotter paper. There's also a property editor on the right for viewing and entering exact values for the points you can't approximate with a mouse, as well as the Inkscape-like features of line colors and weights. There's deep functionality here to help with seams and fitting, and getting good results will take time and patience. Fortunately, there's an active community who will help, a good manual, and various video tutorials to get you started.

From Draft mode a design moves into Piece mode. This efficiently arranges your design elements, or workpieces, in preparation for output much like printing fits images and text onto a piece of paper. Individual workpieces can be exported from here into many different graphical and design formats, including SVG and a huge variety of CAD formats. The step is through the Layout view. This is where the final export will happen for preparing workpieces to cut against material, or to guide the shapes themselves. As a result, the size of a page or sheet can be long, and the Layout view helps you divide sheets into strips, crop them, or unite pages together to make the best use of whatever output you're using. The end result should be the same as those plotter paper drawings, only editable, sharable, and drawn purely in open source software.

Project Website

[UCC:x50-b-bold]1. Draft, Piece, Layout:[/UCC] Each pattern is built from separate blocks, laid out into pieces, and exported in a layout. [UCC:x50-b-bold]2. Measurements:[/UCC] All your designs create exact measurements that can be parametrically scaled. [UCC:x50-b-bold]3. Design:[/UCC] In many ways, Seamly2D can feel like Inkscape for clothing design. [UCC:x50-b-bold]4. Properties:[/UCC] Set exact values and attributes. [UCC:x50-b-bold]5. Layout:[/UCC] See how your designs will look on the page. [UCC:x50-b-bold]6. Point editing:[/UCC] Most designs are built from points and the lines and curves between them. [UCC:x50-b-bold]7. Main view:[/UCC] Create your designs from separate blocks.

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