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3DAI

Free Online STL Editor

Open an STL, 3MF or OBJ file and make the edits a print needs, right in your browser: cut it on a plane, drill a screw hole, lay it flat, merge two files or set an exact size in millimetres. Nothing is uploaded and nothing needs installing.

Free · no signup · your file stays in your browser

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How to edit an STL file online

  1. 1

    Open your file

    Drop an STL, 3MF, OBJ, PLY or GLB up to 100 MB, or try the sample cube. It opens on a print bed with its size shown in mm.

  2. 2

    Edit it

    Move, rotate, scale, mirror or lay it flat. Cut it on a plane, drill holes, add or subtract a box or cylinder, or add a second file. Undo any step.

  3. 3

    Download

    Download a binary STL, or a 3MF that keeps every part separate. Then slice it in Cura, PrusaSlicer, Bambu Studio or any other slicer.

What you can do with this STL file editor

Move, rotate, mirror

Move by exact mm, rotate by 90° or any angle on X, Y or Z, mirror on any axis, center the model on the bed or drop it to the bed.

Exact size in mm

Type the size you need for X, Y or Z, keep proportions or not, scale by percent, or fix a file saved in inches or centimetres.

Lay flat on a face

Click any face of the model and it is turned to lie flat on the bed, the side you want to print on.

Plane cut

Cut along X, Y or Z with a slider and a live preview. Keep the top, the bottom, or both as separate parts. The cut faces are closed, so each piece is solid.

Holes and shapes

Drill a through or blind hole of any diameter, or add or subtract a box or a cylinder, with a preview before you apply it.

Merge files

Add a second STL, 3MF or OBJ next to the first, or keep its coordinates. Join all parts into one solid, or export them separately.

Check and repair

See whether each part is watertight, with counts of open, non-manifold and flipped edges, then run a basic repair in one click.

Private and free

Your file is edited on your own device and never uploaded. No account, no watermark, no limit on edits or downloads.

How it compares with Meshmixer, Blender and Tinkercad

Desktop programs can do far more. This editor is for the common quick fixes before a print, without installing anything.

This STL editorMeshmixerBlenderTinkercad
Runs inBrowserDesktopDesktopBrowser
PriceFreeFreeFree, open sourceFree
Still developedYesNo, Autodesk stopped itYesYes
Best forQuick print fixes: cut, hole, resize, mergeMesh editing and sculptingFull modeling, sculpting and renderingDesigning from basic shapes
File importSTL, 3MF, OBJ, PLY, GLB up to 100 MBSTL, OBJ and othersSTL, OBJ and many othersSTL or OBJ under 25 MB

Go further with AI

The editor is free. When you want more than geometry edits, our AI tools work on the same model (they use credits and need an account):

Texture a 3D model with AIPaint colours and textures on your model from a prompt.Edit a 3D model with a promptDescribe a change in words instead of doing it by hand.Generate a new 3D modelMake a printable model from text or an image.

Frequently Asked Questions

Yes. Open the file on this page and edit it in your browser: move, rotate, scale, mirror, cut, drill holes, add or subtract shapes and merge files. It is free, needs no account and adds no watermark.
You can open STL (binary or ASCII), 3MF, OBJ, PLY and GLB files up to 100 MB. You can download a binary STL or a 3MF in millimetres. A 3MF keeps several parts as separate objects; with several parts you can also download a ZIP with one STL per part.
Open the Cut tab, choose the axis, and move the slider until the orange plane is where you want the cut. Choose to keep the top, the bottom or both, then press Cut. The cut faces are filled, so both halves are closed solids you can print flat side down.
Open Holes & shapes, choose Hole, set the diameter, the direction and a depth (0 goes all the way through), then type the position or press "Place by clicking" and click the model. A red preview shows the hole before you press "Make hole".
Cuts, holes and shapes need a watertight mesh. When a part has holes or broken edges, the editor repairs it automatically and tries again. If that is not enough, it tells you so, and moving, rotating, scaling and mirroring still work. The STL Repair tool shows every problem in detail.
No. The file is opened and edited on your own device and the download is made there too. The only thing loaded from the internet is the geometry engine, the first time you cut or drill. Your model leaves your device only if you choose to send it to the AI texturing studio.

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