Seamly2D is open source patternmaking software that enables designers to create custom-fit garments by reading both standardized multi-size measurement files and individual measurement data. The tool runs on Windows, macOS, and Linux, with distribution through standard installers and package managers including Flatpak.
The software addresses the need for accessible pattern design by allowing users to generate patterns tailored to specific body measurements rather than relying on fixed sizing. Each pattern file can accommodate multiple measurement sources, making it suitable for both standardized production and bespoke custom garment creation. The application is built in C++ using Qt5 and provides a graphical interface for digital pattern drafting.
Seamly2D suits anyone designing custom clothing or exploring pattern-making workflows who values open source tools and cross-platform availability. The project maintains an active user forum and wiki documentation for learning. The tool is particularly relevant for makers, small-scale manufacturers, and fashion enthusiasts seeking to move beyond proprietary design software.
The project demonstrates substantial real-world adoption, with almost all open issues originating from external users rather than the core team. Maintainers respond to new issues and pull requests within hours. Work in the issue tracker centers on bug fixes, enhancements, and Draft mode functionality.
