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STL Repair & Print Readiness

Diagnose and repair broken STL, OBJ, and PLY meshes to a verified watertight solid, and check build volume, wall thickness, overhangs, and material cost in your browser.

Select or drop an STL, OBJ or PLY

Find and fix open edges, non-manifold geometry and flipped faces, orient and scale for printing, check build volume, wall thickness and material cost, and export STL or 3MF.

In-browser processing — files never leave your device.
Full topology diagnostics with on-model defect overlays.
Verified repair pipeline — unverified results are labelled, not hidden.
Build volume, wall thickness, overhang, and material cost checks.

Why ToolBuddy?

No file upload

Your files never leave your device.

Fast browser processing

Processing runs directly in your browser.

STL, OBJ and PLY

Repaired output as STL, 3MF, OBJ or PLY.

Free, no signup

All tools are free forever. No account required.

Know your workflow

Supported files and how to use.

Check supported input/output details and follow the tool steps before exporting.

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Technical specs and decision signals

Use these specs to validate workflow fit, privacy boundaries, and output expectations before you run STL Repair & Print Readiness.

Cost

Free workflow with no signup gate for core usage.

Security

All processing runs in-browser — files never leave your device.

Device

Supports modern desktop and mobile browsers with OffscreenCanvas support.

Tech specs

Input: STL (ASCII and binary), OBJ, PLY. Output: binary STL, ASCII STL, OBJ, PLY, plus a Markdown or JSON report. Estimates are volume-derived approximations, not slicer output; wall thickness is ray-sampled, not exact.

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How to use

Check supported input/output details and follow the tool steps before exporting.

01

Drop or select an STL, OBJ or PLY file, or try the sample mesh.

02

Check the verdict and the list of problems; switch them on under Show on the model to see where they are.

03

Confirm the file's units (the tool suggests inches or metres when a model looks too small) and the up axis.

04

Use Auto-orient and set the size, choose your printer and material, and read the print readiness figures.

05

Click Repair mesh, compare the original and repaired mesh, and download STL or 3MF, or the report.

Guide

Learn, decide, and apply.

Understand how to how to repair an stl and check print readiness in your browser, why it matters in repeat workflows, and when to use this tool with confidence.

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In-browser stl repair and 3d print readiness checks

  • Runs entirely in your browser — files never leave your device.
  • Repair, print-readiness diagnostics, and material estimation in one pass instead of three sites.
  • Every repair is verified by re-analysing the result; an unverified result is labelled, never presented as fixed.
  • Your original mesh stays loaded so you can compare and switch back at any time.
  • Units are explicit, because STL stores none and every physical figure depends on the assumption.
  • Approximations are labelled as approximations, with their assumptions shown.
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Fix broken stl files and validate models before printing

  • Find out why a downloaded STL will not slice.
  • Repair a scanned mesh to a verified watertight solid before printing.
  • Check a model against your printer's build volume before starting a print.
  • Estimate filament mass and cost before committing a spool.
  • Locate walls too thin to print at your nozzle and layer settings.
  • Spot stray shells that inflate a material estimate.
About

About STL Repair & Print Readiness

How to repair an stl and check print readiness in your browserIn-browser stl repair and 3d print readiness checksFix broken stl files and validate models before printing

See exactly what is wrong

Diagnostics report open boundary edges and the loops they form, non-manifold edges and bowtie vertices, inconsistent winding, degenerate triangles, self-intersections, and every separate shell in the file with its own volume.

Each defect class has an overlay you can switch on to see where it actually sits on the model, drawn above the surface so nothing is hidden inside a closed solid.

Repair, then verify

The pipeline welds duplicate vertices, drops degenerate triangles, fills open boundary loops, orients every face outward, and rebuilds the result as a manifold solid.

The result is then re-analysed. It is only described as repaired when that check confirms it is watertight, manifold, consistently wound, and positively oriented — otherwise the remaining defects are named and the result is labelled unverified. Your original mesh stays available for comparison throughout.

Check it against your printer

Set the file's units, pick a build volume and a material, and get dimensions, solid volume, surface area, bed contact area, overhang coverage, filament mass, and cost.

Print time and material figures are derived from volume, not from a slicer, and are shown with their assumptions attached. Wall thickness is sampled by ray casting, so it is reported as a sampled minimum rather than a guaranteed floor.

FAQ

Common questions.

Have more questions? Reach out via our contact page and we will respond within 24 hours.

Do my 3D files upload to a server?

No. STL Repair runs entirely in your browser and never sends your files to a server.

Which formats does it accept?

STL (text and binary), OBJ and PLY, a single file or a ZIP. It exports STL, 3MF, OBJ and PLY, and can write each separate part as its own file.

Why does it ask about inches?

STL stores no unit. When a model would be only a few millimetres across, it was probably made in inches or metres, so the tool offers to switch; every size, volume and cost figure follows the unit you choose.

What does Auto-orient do?

It tries the model on its sides and largest flat faces and keeps the orientation that needs the least support, preferring a large flat base. The overhang figures update straight away.

Does it slice the model or produce G-code?

No. It does not slice, and its time and material figures are volume-based estimates with their assumptions shown, not slicer output.

What happens if the repair cannot fix my mesh?

The result is checked again and, if it is still not watertight and manifold, it is shown as not verified with the remaining problems listed. It is never presented as repaired.

Is the wall-thickness figure exact?

No. Thickness is sampled by casting rays inward from the faces. It finds thin regions reliably but can miss thin spots between samples.

Does repairing change my original file?

Never. The original stays loaded so you can switch back and compare, and the file on your disk is not touched.

Use cases

Popular workflows.

See real workflows where this tool fits naturally, then jump straight into the matching guide.

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Guides

Learn with practical workflow guides.

Read intent-focused guides, then jump straight into the live tool workflow.

View all guides

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STL Repair & Print Readiness use cases

Practical workflows and common jobs you can handle with STL Repair & Print Readiness.

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