Stencils – Images, Text and Shapes as 3D-Printable Spray Stencils

THE IDEA

Stencils – Images, Text and Shapes as 3D-Printable Spray Stencils

Type: Software Status: Beta Tech Stack: TypeScript, Next.js 15, React 19, Tailwind CSS 4, PostgreSQL 16, Drizzle ORM, d3-contour, earcut, three.js, sharp, jose (JWT), OIDC/Keycloak, nodemailer, Web Worker, Vitest, Docker Compose, nginx, GitHub Actions Problem Statement Anyone who wants to 3D-print a logo, lettering or a photo as a spray stencil runs into a physical problem: free-standing islands such as the inside of an “O” drop out of the plate unless bridges tie them to it, and multicolour designs need plates that line up exactly, with registration marks. Without a specialised tool, getting from an image to a printable file means juggling several programs. Makers, airbrush users, cafés making round cocoa and icing-sugar stencils, and clubs that want to share designs on their own instance need an end-to-end solution for this. Description Stencil → STL is a self-hostable web app that converts images, lettering and drawn shapes into physically printable stencils right in the browser: dark areas are cut out of a plate, free-standing islands are automatically tied to the plate with bridges, and the result is output via marching squares and triangulation as a binary STL (or SVG/DXF for plotters and lasers). Multicolour designs are split by colour clustering into matching plate sets with registration marks and a spray order, exportable as a ZIP. Rectangular and round plates (for coffee and dessert stencils, for example), pen and eraser, editable shapes, stencil fonts, undo/redo and a 3D preview make the editor a complete tool. Compute-heavy steps run in cancellable web workers, and when a design is too complex, an optimiser automatically searches for a resolution that can be exported. On the server side, the app adds accounts with email verification, optional Keycloak login, sharing by username, a gallery, public links that can be password-protected, a recycle bin, quotas, an audit log and an admin area. Operation is prepared via Docker Compose with an nginx proxy, automatic PostgreSQL backups and restore checks, and is backed by an extensive Vitest suite with CI. Use Case A logo, photo or piece of lettering becomes a stencil in a few clicks, ready to 3D-print and use for spraying, painting or dusting — in several colours and in perfect register, too. Link: https://github.com/rawk7000/Stencils (private repo) “My Stencils” overview: saved drafts with plate dimensions, plus multicolour examples to try out. Editor: a logo stencil on an A4 plate — free-standing islands are automatically tied to the plate with bridges (red). 3D preview of the finished stencil as a rotatable model, with dimensions and triangle count. Round café stencil (Ø 100 mm) with stencil lettering and editable circle shapes. Multicolour stencil set: simulated colour preview of all spray passes, with a base plate and two colour-detail plates. Single plate of the set: the base shape with two identical registration marks for accurate overspraying. Export check: the optimiser confirms the resolution; export as STL, SVG or DXF. Set export: all three plates as an STL ZIP, or each plate individually as STL, SVG or DXF. Sharing dialog: share by username or via a public link with optional password protection. Admin area: create accounts, assign roles and reset passwords.