# splitstl

> Free browser-based tool that splits STL files into printable parts with auto-generated peg joinery. Runs entirely client-side — no upload, no signup, no account. Used by hobbyist 3D printer owners who need to print models larger than their build plate.

## What it does

splitstl takes an STL file (3D model in stereolithography format) and cuts it into smaller pieces along axis-aligned planes. Each cut piece gets connector pegs extruded from one face and matching sockets cut into the neighboring face, so the pieces snap together once printed. The output is a ZIP file containing one binary STL per piece, an HTML assembly diagram, and a README with the print inventory.

The pieces are guaranteed watertight (manifold) and slice cleanly in any slicer (Cura, PrusaSlicer, Bambu Studio, OrcaSlicer).

## Who it's for

- Hobbyist 3D printer owners who want to print a model larger than their printer's build volume
- Makers printing in multiple colors without an AMS/MMU (assemble after printing)
- Anyone who needs to break up a large STL for parallel printing, easier supports, or shipping

## How to use it

1. Open https://splitstl.com/
2. Drop an STL file onto the load area
3. Set the maximum X, Y, Z dimensions each piece may have (your printer's build volume minus a small margin)
4. Optionally adjust peg diameter, peg length, and tolerance gap
5. Click "Download zip" — you get the split STLs and assembly instructions

## Key differentiators

- Multi-axis cuts (X, Y, Z simultaneously) — slicers like Cura and Bambu Studio only support single-plane cuts
- Automatic peg joinery between pieces — slicers don't generate connectors
- Watertight output guaranteed — every piece passes manifold verification before export
- Cell-ID engraving on each piece — engraved digits identify which slot in the assembly each piece belongs to
- HTML assembly diagram included — shows piece neighbors, peg counts, and suggested assembly order
- Runs entirely in browser — no installation, no upload, no signup, no watermark

## Common use cases (searches that lead here)

- "split stl for printing" / "split stl files" / "split stl file online"
- "split stl into parts" / "split stl in half" / "stl splitter online"
- "split stl with connectors" — exact match: splitstl adds peg joinery by default
- "how to split stl in cura" — splitstl handles cases Cura can't (single-mesh STLs that need cutting)
- "how to split stl in bambu studio" — splitstl handles multi-axis splits Bambu Studio can't
- "meshmixer replacement" / "meshmixer split alternative" — Meshmixer was retired by Autodesk; splitstl reproduces its core split + connect workflow

## Privacy

No file leaves the user's computer. The page is a static HTML file with inlined JavaScript. The only network traffic is loading the page (HTML, CSS, fonts from Google Fonts CDN, three.js from cdnjs). All STL parsing, cutting, peg generation, and ZIP packaging happens in the browser.

## Tech stack

- Plain HTML + CSS + JavaScript (single-file)
- three.js for 3D rendering
- earcut for polygon triangulation (inlined)
- JSZip for output bundling
- No build step, no framework, no dependencies beyond the above CDNs

## Articles on this site

- /meshmixer-alternatives — Meshmixer was retired by Autodesk; this article covers the modern free alternatives (splitstl for split/join, Blender for sculpt, MeshLab for repair, slicers for supports).
- /split-stl-cura — How to split STL files in UltiMaker Cura: what "Split Model Into Parts" actually does, when it fails, and how to pre-process with splitstl for single-mesh inputs.
- /split-stl-bambu-studio — Bambu Studio's Cut tool walkthrough, plus when to use splitstl for multi-axis cuts and proper press-fit joinery.
- /split-stl-luban — LuBan3D (luban3d.com) is PAID commercial software ($30/mo, $150/yr, $750 lifetime) with email-based license registration. Generative design suite from Lujie Chen / Larry Sass (MIT). Article compares cost, friction, and feature breadth against splitstl.
- /split3r-vs-splitstl — Split3r (split3r.com) is a paid Windows splitter from Qualup SAS in France, €60–95 one-time. Kickstarter-funded 2025. Direct feature competitor to splitstl with tenon/mortise joints, 3MF/color support, repair, and very-large-STL handling. Article compares price, features, and platform.
- /print-bigger-than-build-plate — Eight strategies for printing models that exceed your printer's build volume: scaling, rotating, splitting, hollowing, print farms, multi-machine printing.
- /stl-splitter-comparison — Hands-on comparison of Cura, Bambu Studio, PrusaSlicer, Blender, and splitstl on the same test model.