PartFit 3D

Name: PartFit 3D
Author: Serpit G

For 3D printing engineers: PartFit 3D splits oversized STL and 3MF models into printer-ready parts so you print complex designs without assembly.

Built by Serpit G · Productivity · Developer Tools · Design Tools · Free

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Serpit G (Joined Aug 2026)

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Launched on Launch Llama Aug 10, 2026 · #100 of 108 that day

About

PartFit 3D is a private, browser-based STL and 3MF splitter for 3D printing. Orient oversized models, make repeated plane cuts, check every result against a configurable printer build volume and safety margin, inspect mesh issues, and export slicer-ready STL or 3MF parts. Model processing stays on your device, with no upload or account required.

Use Cases

Splitting an oversized STL or 3MF model into parts that fit a desktop 3D printer's build volume without assembly
Cutting a large cosplay helmet or armor model into printable sections and verifying each part is watertight before slicing
Preparing large figures, statues, or architectural models by choosing an orientation and cut planes, then exporting 3MF or STL parts

Who it is for

3D printing engineers preparing models for desktop printers
Cosplay makers printing helmets and armor pieces
Hobbyists and makers printing large figures or terrain models

Pricing

PartFit 3D is free to use. See the website for details.

View PartFit 3D pricing →

FAQ

Does PartFit 3D upload my model?

No. In this first release, parsing, checking, cutting, and exporting happen in your browser.

Can I keep cutting a part that is still too large?

Yes. Select any Too Large part, choose a new axis and position, then cut again until every part fits.

Does the cutter close the open surface?

Yes. PartFit reconstructs the boundary at the cutting plane, caps both results, then reruns boundary, non-manifold, and watertight checks.

Will it repair a broken STL?

The separate STL repair tool can attempt supported mesh repairs. Cutting also checks boundaries and non-manifold edges, and blocks export for severe topology errors. Some damaged or self-intersecting models still need a dedicated mesh editor.

Can I enter a custom build volume?

Yes. Choose Custom and enter the usable X, Y, and Z dimensions for your printer.

Can I use 3MF?

Yes. Import STL or 3MF, then export all verified parts as one 3MF project or as a ZIP of STL files.

Can PartFit divide a model into equal parts?

Yes. Professional mode lets you choose 1–6 divisions independently on the X, Y, and Z axes, preview the resulting planes, and apply them together.

Can I add more than one cutting plane?

Yes. Add multiple X, Y, or Z planes, drag each position independently, and execute the complete set in one operation.

Can PartFit create alignment pins and sockets?

Yes. Professional mode can generate one, two, or four printable pins with matching clearance-adjusted sockets directly on the cut surfaces.

Why does PartFit use a printer safety margin?

The safety margin reserves space for brims, clips, calibration differences, and conservative fit checking instead of assuming every advertised millimeter is usable.