Edit STL files online, free. Scale to exact dimensions, combine with shapes, hollow, repair non-watertight meshes and export print-ready STL or 3MF. No install.
Open an STL, resize it to spec, combine it with other shapes, hollow it out and repair it for printing, then export print-ready STL, 3MF, OBJ or GLB. Free, no install, no sign-up to start.
Free to use · Runs in your browser · Start without an account
Most “STL editors” online only let you look, scale, and rotate. OwlCAD actually edits: combine, hollow, repair and re-export.
Drag an .stl onto the build plate, and units are detected and corrected on the way in. No install, no sign-up to start; your work autosaves in the browser.
Move, rotate, and scale with snapping gizmos, or type exact millimetre values. Lay the part flat to a face and scale it to fit your printer’s build volume.
Boolean union, subtract, and intersect your STL against parametric primitives: add a mounting tab, cut a hole, or merge two prints into one.
Shell a solid into a printable wall thickness and add drainage holes: less filament, faster prints, the same outer shape. The print check tells you what the part will weigh and cost in filament, so you can see exactly what the hollowing saved.
The print check flags non-watertight (non-manifold) geometry, thin walls, and overhangs, reports volume and triangle count, and repairs the mesh before it reaches your slicer.
Save print-ready STL or 3MF for any slicer, or OBJ and GLB for other 3D tools, as clean geometry ready to go.
No download, no account needed to begin, and your work saves in the browser as you go.
It opens on your device, it is saved to your workspace as you work, and it exports back out in the format your slicer wants.
Your browser reads and renders the model itself, so it appears as soon as you drop it in — you are never queued behind anyone else’s upload, and the file does not travel anywhere before you can see it.
Most online viewers forget your file the moment you close the tab. OwlCAD keeps the model in your own workspace and syncs it as you work, so it is still there when you come back to this browser. Create a free account and it follows you to any device, and your projects dashboard lets you delete anything you no longer want.
When you are done, export STL, 3MF, OBJ, GLB or STEP — the format your slicer or your colleague actually needs, not a project file that only opens here.
Yes. OwlCAD runs in your browser with nothing to install, and you can open and edit an STL without an account, and your model is saved to a workspace as you go, so it is still there when you come back. Editing and exporting are free; only AI generation is part of the paid Pro plan.
Open the editor and drag your .stl onto the build plate (units are detected on import), then move, rotate, and scale it to exact dimensions, combine it with parametric shapes using boolean union, subtract, and intersect, hollow it into a printable shell, or nudge faces, edges and vertices, then export it again.
Yes. The built-in print check flags non-manifold geometry, thin walls, and overhangs, reports the volume and triangle count, and can repair the mesh so it is watertight before it reaches your slicer.
Print-ready STL and 3MF for any slicer, plus OBJ and GLB for other 3D tools. Imported meshes can also be combined with native OwlCAD solids before export.
You can export any scene to STEP, and an imported STL comes through as a faceted solid, but not as an editable analytic solid, because an STL has no solid B-rep to recover. The parametric solids you build in OwlCAD (primitives, booleans, fillets, and more) export as true editable B-rep; imported meshes export as faceted shells.
Select the mesh and type the size you want into the Dimensions fields. Keep proportions locked to scale the whole model, or unlock them to set each axis on its own. STL files record no units, so a model authored in inches lands 25.4× too small: the bar shown on import reinterprets the file as millimetres, centimetres, inches, or metres in one tap, previewing the resulting dimensions before you accept.