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● peg side ● socket side
splicestl is a free online STL splitter — an automatic in-browser tool that cuts STL and 3MF files into parts with auto-generated connectors (also called joinery, pegs, or dovetails) so the pieces snap together once printed. Drop in any STL, set the maximum dimensions your printer can fit, and the tool slices the model into chunks. Everything runs locally in your browser — your files are never uploaded.
Whether you want to split an STL in half, cut an STL into multiple parts, split STL with connectors that hold the parts together, split a 3MF with color preservation, or generate molds, this is the tool for you. Common use cases: printing models larger than your build plate, multi-color prints without an AMS, parallel printing across multiple printers, repairs and modifications, easier shipping and storage.
Cut large STL files into press-fit pieces with auto-generated joinery. 7 joinery modes, 6 cut shapes, print farm mode with cost & time estimates, 152 printer presets + custom printers, mesh repair, AutoShell hollowing, 3MF multicolor preservation.
→ open splicestl (this page)Generate two-part 3D-printable molds from any STL master. Silicone, resin, plaster, and wax casting presets. Configurable wall thickness, clearance, pour spout, vents, and alignment keys. Same Manifold WebAssembly engine as splicestl. In active development — inspect output before printing.
→ open splicestl/moldMost slicers can split a model along a single plane. That works for cutting something in half. It doesn't work when your model needs three cuts across multiple axes, or when you want the pieces to lock together.
| Feature | splicestl | Cura split | Bambu Studio | Orca Slicer | Meshmixer |
|---|---|---|---|---|---|
| Multi-axis cuts (X, Y, Z simultaneously) | ✓ | single plane | single plane | single plane | manual |
| 7 joinery types (peg, dovetail, finger, etc.) | ✓ | none | alignment dowels only | alignment dowels only | manual |
| 6 cut shapes (flat / wave / zigzag / sawtooth / brick / pyramid) | ✓ | flat only | flat only | flat only | manual |
| Print farm mode (multi-printer allocation) | ✓ | no | no | no | no |
| Watertight output guaranteed | ✓ | ✓ | ✓ | ✓ | manual repair |
| Non-manifold edge repair built in | ✓ | no | no | no | manual |
| 3MF splitter with color preservation | ✓ | no | no | no | no |
| Assembly diagram included | ✓ | no | no | no | no |
| Runs in browser | ✓ | desktop app | desktop app | desktop app | discontinued |
| Free, no signup, no upload | ✓ | ✓ | ✓ | ✓ | unsupported |
If you used Meshmixer to split models, that tool was retired by Autodesk and is no longer updated. splicestl reproduces its core "split + connect" workflow in a modern browser.
Joinery — also called connectors in 3D-printing circles — determines how the split pieces connect after printing. splicestl supports 7 connector types out of the box; the defaults work for most cases. Each connector mode has independent size, length, and tolerance controls for your filament's shrinkage:
The cut surface itself can interlock and provide shear resistance — useful even with peg joinery, and the whole point of "no joinery" mode.
If you have multiple printers, the print farm mode spreads pieces across them so they all finish around the same time. Each printer row has its own build volume (X×Y×Z), throughput (mm³/s), allocation percentage, and optional filament price override (for multi-material farms running PLA on one printer and ABS on another).
Click Auto-balance to set allocations proportional to throughput so the slowest printer doesn't bottleneck the wall-clock time. Click Split equally to give every printer the same share regardless of speed. After splitting, pieces are assigned via LPT (Longest Processing Time) greedy allocation, sorted by volume — provably within 4/3 of optimal makespan.
The download zip groups each printer's pieces into its own subfolder, named after the printer. Drag a folder straight into the slicer for that machine.
splicestl/mold is a separate browser-based tool for generating 3D-printable casting molds from any STL master model. The tool is currently in alpha — it works reliably for simple/convex shapes (figurines with clean bases, geometric forms, architectural elements), but may produce unusable geometry on highly organic forms or models with deep undercuts. Inspect output before printing.
Upload your master (a figurine, an architectural form, a custom part), and the tool generates a two-part mold box with the cavity carved out, alignment keys on the parting face, a pour spout from the top, and air vents for trapped pockets.
Material presets cover the four most common casting materials: silicone (for flexible molds and finished silicone parts), epoxy or UV resin (for rigid clear/colored casts), plaster or concrete (for solid pours), and wax (for investment casting masters). Each preset configures wall thickness, clearance, spout diameter, and vent count to sensible defaults for that material's viscosity and shrinkage behavior.
The same Manifold WebAssembly engine that powers splicestl handles the boolean operations: block minus master gives you the cavity, splitByPlane gives you the two halves, and cylinder subtractions cut the spout and vents.
Load your STL into the tool at the top of this page, set the maximum dimensions each piece may have (usually your printer's build volume minus a few millimeters of margin), and download the zip. You'll get one STL per split piece, ready to slice and print.
Yes. splicestl runs entirely in your browser. There is no signup, no upload, no account, no watermark, no AI processing, and nothing happens on a server — your STL file never leaves your computer.
Cura's "split into parts" only works if the STL already contains multiple disconnected mesh objects — it doesn't cut a continuous model. splicestl actually cuts the geometry along axis-aligned planes and generates joinery between pieces. If your model is a single solid mesh that's too big for your printer, Cura can't help you; splicestl can.
Bambu Studio can perform a single-plane cut on a model, with optional alignment dowels. It doesn't generate multi-axis cuts (e.g. splitting a model into a 2×3 grid simultaneously), and it doesn't add real press-fit joinery — the dowels are alignment-only. splicestl handles both.
Meshmixer was retired by Autodesk in 2021 and is no longer maintained. splicestl provides the same "split STL + add connector pegs" workflow that Meshmixer's Plane Cut and Append features were used for, but in a modern browser tool with no installation.
Default press-fit square pegs work for almost everything. Switch to dovetails for thin-walled pieces (pegs would split the wall). Use finger joints for long flat cuts where you want maximum glue surface. Use magnet pockets if you want a non-permanent snap-together assembly. Use dowel holes when you want to align pieces precisely with a separate (often stronger than printed) rod.
Default flat works for most cases. Use wave or zigzag if you want the seam to look organic / less obviously machine-cut. Use brick if you want lateral interlock without adding pegs (great with "none" joinery mode). Use sawtooth if you specifically want a one-way ratchet that resists motion in one direction only.
Set the maximum dimension along one axis to half the model's bounding-box size on that axis, and leave the other axes unconstrained. The tool computes a single cut at the midpoint and emits two STLs with matching pegs. Alternatively, use "N pieces per axis" mode and set the count to 2 on the axis you want to split.
For PLA, 0.15–0.2 mm clearance per fit gives a firm press-fit that doesn't need glue but can still be disassembled. PETG needs 0.3–0.4 mm (more shrinkage), ABS needs 0.4–0.6 mm. splicestl's default 0.2 mm tolerance is calibrated for PLA at the default 0.4 mm nozzle. Print a test peg before committing to a 30-piece split — extruder calibration and slicer settings can shift the effective fit by ±0.1 mm.
Four common approaches, in order of strength: press-fit pegs (no glue, can disassemble — use splicestl's default pegs), glue with alignment dowels (strongest permanent bond, use cyanoacrylate or epoxy + Bambu/Orca-style dowel pegs), magnets (snap-together, removable — use splicestl's magnet-pocket mode with N52 disc magnets), or mechanical fasteners (screws into printed bosses). For interlocking that resists shear without any of these, use splicestl's brick cut shape — the stepped square-wave parting line locks pieces against lateral motion.
Most common cause: filament shrinkage exceeds the tolerance gap. Try a wider tolerance (0.3 mm for PLA, 0.4 mm for PETG). Second most common: the printer's extrusion width is slightly oversized, making everything ~0.1 mm bigger than designed. Calibrate your extruder's flow rate. Third: the cut surface has stringing or elephant's foot blocking the seam — clean both faces with a deburring tool before assembly. splicestl's tolerance setting in the joinery panel lets you regenerate the same split with a wider gap without restarting.
Yes. If your STL has open edges, T-junctions, duplicate triangles, or inverted winding (the common "non-manifold" defects), splicestl shows a banner with a one-click repair option. The repair runs vertex weld → degenerate triangle removal → small-hole close → winding consistency check. After repair, the mesh is verified manifold before splitting. You can also dismiss the banner — repair will then run automatically as part of the split path if it's needed.
You don't print silicone directly with a regular 3D printer — silicone needs specialized equipment. What you DO print is the mold box (the rigid outer shell), then pour liquid silicone into the box around your master model. After cure, you peel the printed mold box off and the silicone mold is your finished product, ready to cast resin / plaster / wax / etc. The splicestl/mold tool generates these printable mold boxes from any STL master, with material presets for silicone, resin, plaster, and wax casting.
Yes, via the splicestl/mold tool (currently alpha). It takes any STL master and generates a two-part 3D-printable casting mold, with material presets for silicone, resin, plaster, and wax. Configurable wall thickness, clearance, pour spout, air vents, and alignment keys. Works reliably for simple/convex shapes; complex organic forms or deep undercuts may produce unusable geometry — inspect before printing.
Yes. If your maximum dimensions require multiple cuts on any axis, the tool generates them all. A large model can be split into 4, 8, 27, or more pieces depending on how aggressively you constrain it. Print farm mode then assigns those pieces across multiple printers if you have them.
No. splicestl is a static HTML page that runs entirely in your browser. The mesh splitting, joinery generation, mold generation, and watertight verification all happen client-side using JavaScript + WebAssembly. The only network traffic is for loading the page itself.
Use alignment features at the seam plus adhesive. splicestl generates the joinery for you — pegs, dovetails, tenon/mortise, finger joints, magnet pockets, or dowel holes — so parts register precisely; add CA glue or epoxy on the mating faces for a permanent bond.