Split 3D models online

Cut an STL, OBJ, or 3MF model in half along any axis with clean capped faces. Split large models into printable parts, free and in your browser.

Split the attached model along the Z axis at 50%

Files are processed entirely in your browser. Nothing is uploaded to a server.

Any 3D edit is just a prompt away.
Try the full chat free

How to cut an STL in half online

Attach the model, pick a cut axis, and drag the slider. The blue plane in the preview shows exactly where the cut will land. Press "Split it" and download the two halves as separate STL files, each capped with a flat solid face so slicers treat them as watertight parts.

Splitting is the standard trick for printing models bigger than your build plate, or for getting a perfectly flat surface to print on without supports.

Frequently asked questions

How do I join the printed halves back?

Superglue works for PLA and PETG. For stronger joints, cut where the cross-section is largest and add alignment pins, or ask GrandpaCAD chat to generate a pinned joint for your exact part.

Why did the split fail on my file?

Boolean cuts need reasonably clean geometry. If the model has holes or self-intersections, run it through the STL repair tool first, then split the repaired file.

Can I make more than one cut?

Yes. Split, download a half, then attach that half again and cut it further. Repeat as needed for very large models.

More free 3D file tools

View a model Repair a model Reduce file size Convert 3D files Measure a model Scale a model Mirror a model Print weight & cost

Describe a part. Get a printable model.

GrandpaCAD turns a text prompt into a ready-to-print 3D model. Functional parts, organic shapes, multi-color prints. No CAD skills needed.

"Phone stand with cable slot, 70mm wide, 15 degree angle"

Generate your first model3 free generations, no card required

Back to Tools