Printer-aware split
Use your build volume, margins, orientation, and fragile geometry instead of a generic cube grid.
Calibrated assembly
Split large STL models into parts that fit back together.
Fit oversized models to your real build volume, rank cleaner seams, add calibrated connectors, and print a test from the actual joint before the full project.
Last reviewed
Expected outcomePrintable pieces, calibrated joinery, and a clear assembly plan.
Why splitting is more than cutting.
A model that exceeds your build volume has to be cut, and the cut decides how the finished part looks and how strong it is. A seam through a face, a line of text, or a thin wall shows after assembly, or breaks first. The build dimensions on the spec sheet also overstate usable space, because brims, skirts, supports, and the margins your printer needs all take room.
Joinery adds a second problem. Pins and sockets printed at nominal size usually do not fit. The right gap depends on the printer, the material, the print orientation, and the connector shape, and no clearance value works for every joint.
Meshworthy plans the split against your usable envelope, ranks candidate seams, and calibrates clearance with a test that you print from the real connector.
Checks included in this workflow.
Meshworthy shows the affected geometry, applies the selected constraints, and checks the exported result. Limitations remain visible when a result requires manual review.
Natural seam ranking
Prefer creases and less visible regions while protecting detailed surfaces.
Calibrated joinery
Tune clearance by printer and material instead of trusting a universal tolerance.
Actual-joint test
Export a small test containing the real final-scale connector before a long print.
From build volume to a fitted joint.
01Set the envelope
→Enter the build volume and the margins that remain after brims, supports, and placement.
02Choose a seam
→Compare ranked cuts by visibility, orientation, support cost, strength, and assembly access. Mark faces and thin features that must not be cut.
03Configure joinery
→Pick printed plugs or separate pins, then review socket walls, insertion direction, and rotation control.
04Print the real joint
Export a small test with the final-scale connector and the wall around it, print it, and apply the clearance that fit.
What is free and what needs Pro.
Splitting and joinery are part of the one-time Meshworthy Pro unlock, with no subscription. Diagnosing the model and measuring it are free in the Mac app.
You can start calibrating before you buy anything: the free 3D Print Clearance Test generates a six-position fit test for round pins, square keys, dovetails, or magnet pockets in your browser.
What this does not do.
- Meshworthy checks geometry and assembly planning. It does not rate the mechanical strength of a finished joint, so load-bearing or safety-critical parts need material-specific testing.
- A clearance that fits one printer and filament is calibration evidence for that setup, not a tolerance for every printer or material.
- Meshworthy does not generate supports, print settings, toolpaths, or G-code. Your slicer still prepares each piece for printing.
How to split an STL so the parts fit.
Plan build volume, seam position, strength, connector clearance, and a test coupon from the actual joint.
More guides on this topic
About calibrated assembly.
Can it add alignment pins?+
Yes. Meshworthy supports printable connectors and separate-pin workflows, including common stock-pin sizes.
Will the pieces fit my printer?+
Candidates are checked against the selected build volume. Connector walls and clearances are validated at final scale.
Can I choose the cut myself?+
Yes. Automatic proposals remain editable, and protected regions let you tell Meshworthy where not to cut.
Why does clearance depend on my printer?+
Nominally identical holes fit differently across printers, materials, and print orientations. Meshworthy ties clearance to a test printed from the real joint instead of a default value.
How do I test a connector before printing the whole model?+
Export an actual-joint test that contains the final-scale connector and its surrounding wall, print it, and record which position fits. The free clearance test in your browser covers generic connector types.
Does splitting keep the colors of a 3MF model?+
A cut creates new triangles that need new color assignments. The 3MF integrity checks report which colors and materials an operation preserves, remaps, or cannot support before you export.
Know before you print.
On the Mac App Store. Diagnosis is free; Pro unlocks repair and preparation for $19.99, once — never a subscription. Model processing stays local.
Get Meshworthy for Mac ↗