3D Model Splitter: Split & Cut STL Files Into Printable Parts With Pegs, Dowels and Dovetails
The PrintPal 3D Model Splitter is a free online tool that cuts any 3D model into multiple parts so it fits your printer, then adds the alignment pegs, dowel holes or dovetail joints you need to glue it back together perfectly. Upload an STL, OBJ, 3MF, GLB, GLTF or PLY file, place one or more cutting planes, pick a connector style, and download every part as an STL ZIP or a single 3MF project with all the pieces already arranged on your build plate. Everything runs in your browser using WebAssembly — your model never leaves your computer.
Why split a 3D model before printing?
Most consumer 3D printers have a build volume between 180 and 256 mm on each side. Busts, cosplay props, helmets, terrain tiles, architectural models, signs and life-size figures are routinely larger than that. Splitting the model into parts is the standard way to print big objects on a small printer, and it has other benefits too:
- Print oversized models on any printer by cutting them into bed-sized sections.
- Eliminate supports by cutting a model at the point where an overhang starts and printing each half on its flat cut face.
- Print in multiple colors without a multi-material system: print each part in a different filament and assemble.
- Reduce failure risk — a 30-hour print that fails at hour 28 hurts; three 10-hour prints don't.
- Improve surface quality by orienting each part independently so its most visible surface faces up.
How to split an STL into parts with pegs (step by step)
- Load your model. Drag and drop an STL, OBJ, 3MF, GLB/GLTF or PLY file. The splitter centers it on a virtual build plate and reports its size.
- Choose your printer bed. Pick a preset (Bambu Lab A1 mini, P1S, X1C, H2D, Prusa MK4, MINI, XL, Creality Ender 3, K1, Elegoo Neptune, Anycubic Kobra and more) or type custom X / Y / Z dimensions. The tool shows immediately whether the model fits.
- Add cut planes. Click Auto-place cuts to fit the bed for the fewest cuts that make every part fit, or add X, Y or Z planes yourself. Drag a plane in the 3D view or use the position slider, and tilt it for angled cuts.
- Pick a joint. Choose Pegs (pins on one part, matching holes on the other), Dowels (holes on both parts plus separate printable pins), Dovetail (a sliding tapered rail), or None for a plain flat cut. Set the diameter, depth, clearance, count and taper.
- Preview the assembly. Use the exploded view slider to pull parts apart and check every connector. Each part is color-coded and listed with its dimensions and a bed-fit check.
- Export. Download an STL ZIP with one file per part (plus dowel pins), a single 3MF with every part laid flat and arranged on your plate, or one assembled STL.
Connector types explained
Pegs & holes (plug joint)
The classic slicer-style connector: cylindrical, square or hexagonal pegs are added to one part and matching holes are subtracted from the other. Pegs align the parts perfectly and hide the seam. Set a clearance of 0.15 – 0.3 mm for a snug press fit, and a small taper of 2 – 5° to make insertion easy.
Dowels (separate pins)
Both parts receive holes and the tool generates the dowel pins as separate printable parts. Dowels let every part lie perfectly flat on its cut face (no protruding pegs), print stronger because the pin is a solid separate object, and are the best option for large heavy parts or multi-color assemblies.
Dovetail (sliding joint)
A tapered rail on one part slides into a matching slot on the other. Dovetails can be assembled and disassembled without glue, lock in two axes and are ideal for modular terrain, display bases and props that need to come apart. Adjust neck width, height, flare angle and clearance.
Plain cut (no connector)
A flat planar cut with no added features. Use it when you'll align parts by eye, when you plan to add your own magnets or pins, or when you simply want to separate a model into sections to print in different colors.
Recommended settings for FDM printers
| Setting | Typical value | Notes |
|---|
| Peg diameter | 4 – 8 mm | Larger pegs for bigger, heavier parts. 6 mm is a good all-round default. |
| Depth per side | 5 – 12 mm | Deeper pegs align better; keep at least 2 mm of wall around every hole. |
| Clearance | 0.15 – 0.30 mm | 0.2 mm is right for most well-calibrated printers. Increase for a looser slip fit for glue. |
| Taper | 2 – 5° | Tapered pegs self-center and tolerate slight first-layer squish. |
| Dovetail flare | 8 – 15° | Steeper angles lock harder but need more clearance. |
| Pegs per face | 2 – 3 | Two pegs stop rotation; three keep large faces flat. |
3D Model Splitter vs. the cut tool in Bambu Studio, OrcaSlicer and PrusaSlicer
Bambu Studio, OrcaSlicer and PrusaSlicer all include a Cut tool with connectors (plugs, dowels and snaps). This online splitter does the same job with a few extra conveniences: it runs in any browser with no install, it can auto-place the fewest cuts needed to fit a chosen printer bed, it supports several cut planes at once, and it exports a slicer-neutral 3MF or STL ZIP you can open in any slicer, including Cura, ideaMaker, Simplify3D and Creality Print, or send to a friend or a print service. It is also a quick alternative to Meshmixer's plane cut, Microsoft 3D Builder's split tool, Blender's bisect and Tinkercad workarounds when you only need a clean cut and a way to line the pieces up again.
Tips for assembling split 3D prints
- Print all parts with the cut face on the bed for the strongest glue joint and a seam that disappears.
- Use CA (super) glue or a two-part epoxy for PLA and PETG; plastic weld or acetone for ABS/ASA.
- Test-fit a peg before gluing. If it is too tight, re-export with 0.05 mm more clearance rather than sanding.
- For painted props, fill the seam with UV resin, Bondo spot putty or filament-friendly filler primer, then sand.
- Dowel pins can be printed in a contrasting color as a design feature, or replaced with 3 mm / 5 mm metal rods.
Frequently asked questions
Is the 3D model splitter free?
Yes. Splitting, previewing and adjusting connectors is free with no watermark and no file limits. A free PrintPal account is required to download the finished parts.
Which file formats can I split?
STL (binary and ASCII), OBJ, 3MF, GLB, GLTF and PLY. Exports are STL (ZIP or single file) and 3MF.
Does my model get uploaded?
No. The mesh is cut inside your browser using the Manifold geometry engine compiled to WebAssembly. Nothing is sent to a server until you choose to publish a part on PrintPal.
My model says it is not watertight. What now?
Boolean cutting requires a closed, manifold mesh. Run it through the free PrintPal Mesh Repair tool first, then load the repaired file here.
Can I cut at an angle?
Yes. Every plane has two tilt controls so you can make angled cuts that follow a model's natural seam lines or hide the joint under a fold or edge.
Can I split a model into more than two parts?
Yes. Add as many planes as you need on any axis. The auto-fit button calculates the minimum number of planes to fit your chosen bed size.
Will the 3MF open in my slicer?
The 3MF is written as separate objects arranged on the plate and opens in Bambu Studio, OrcaSlicer, PrusaSlicer, Cura and most other slicers. Use the STL ZIP if your slicer does not import 3MF.
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3D Model Splitter — Cut Models Into Parts With Pegs & Holes