Cut an STL into parts that fit back together
Move the red plane to where the model should be cut, choose pegs or pins if the parts should lock together, and cut. Each part can be cut again, so a model too big for the bed becomes as many pieces as it needs.
Saves model files for your slicer, never printer code. Opened and sliced in PrusaSlicer, OrcaSlicer, Bambu Studio and Cura.
Pegs that do not twist
Choose round or square and how many — 1, 2, 3, 4 or 6. They go where the cut face has room for them, kept clear of the outside wall and of any hole that crosses the cut. Two or more round pegs, or a single square one, stop the parts turning against each other; if only one round peg fits, the page says so. If the face is too narrow for the size you set, smaller pegs are used and you are told. The hole is wider than the peg by the gap you set — 0.2 mm suits most FDM printers; make it 0.3 mm if your parts come out tight.
Pins printed separately
Choose “holes in both, pins printed separately” and both parts get a hole, with the pins added as their own parts, standing in a row beside the model so they print without supports. A pin that breaks or gets lost is easy to reprint.
Saving the parts
3MF keeps every part as its own object in one file, so the slicer shows them separately and you can arrange them on the bed. Or tick “each part as its own file” to get a zip of separate STL files.
Questions
- Does the model have to be watertight?
- Yes — a cut needs to know what is inside and what is outside. If the model has holes it is repaired first, automatically, when you open it on this page.
- Can I cut at an angle?
- Yes. Type a tilt in degrees around the two other axes, or switch to Turn above the view and drag a ring on the red plane.
- How do I keep only one half?
- Set “Keep” to only above or only below the plane before cutting.