Check your model before you slice.

Choose an STL or OBJ 3D model to check for gaps, faces pointing the wrong way and disconnected parts. Preview supported fixes in your browser.

Start with your model

Choose an STL or OBJ file to inspect here. It stays on your device; previewing a repair is a separate step.

STL / OBJ

Select an STL or OBJ ↗

LocalInspect files up to 100 MB in your browser.

Fig. 1Animated sample · counts belong to this demo mesh Scanning

Triangles: 0
Open edges: 0
Boundary loops: 0
Parts: 1

Or try the demo helmet ↓

Inspector

Inspect your model before slicing.

The demo helmet has a few small defects added for this page; its counts describe the modified demo, not the original model. Choose an STL or OBJ above to inspect your own model here. It replaces the demo and stays in your browser. Preview repair shows supported changes on a separate copy, so the original file stays unchanged. This browser prototype is separate from Make Manifold and Helmet Foundry.

Fig. 2Drag to rotate. Pinch to zoom. Bed grid 10 mm

Release to inspect locally

Futuristic helmet (sample)

Reading

Watertight means the mesh surface is closed. It does not guarantee a successful print.

Triangles: 0
Vertices: 0
Size, mm: 0
Enclosed volume: 0

STL and OBJ files may not specify units. YO3D displays coordinates as millimetres, so check the size against your intended dimensions before slicing.

An open edge belongs to one triangle. Connected open edges form a boundary loop around a gap; loop count does not show the gap’s size.

Replace model

Preview supported changes on a copy, then check the result in your slicer before printing.

Model fileLocal only

Mesh issues this prototype can inspect.

These percentages show how often conditions appeared in the historical Thingi10K study of 10,000 3D models. A model can have more than one condition; the figures are not YO3D test results or a prediction for your file. This prototype checks open edges, boundary loops, face direction, non-manifold edges and disconnected parts. When a file loads, it joins triangle corners at matching positions and removes zero-area or duplicate triangles. Preview repair can fill some openings and correct some face directions. It does not check surfaces that cross through themselves or guarantee a successful print.

A gap can interrupt a print path.

SliceSlicer software turns the model into layer-by-layer printer paths.
Open edgeA gap can leave one of those paths incomplete.
Repair previewFor some openings, YO3D previews new faces across the gap.
ReviewCompare the preview with the original before exporting.

Illustration only · not generated by a slicer

Layer0 / 64 Open paths shown0 Illustrated pathOpen

      10% had inconsistent face directions
Flipped facesNeighboring triangles should face consistently. The inspector flags direction conflicts within a connected part of the mesh.
Orientation preview

      STL lists each triangle’s corners
Duplicate verticesSTL stores every triangle separately. YO3D joins corners at matching positions so it can check how the triangles connect.
Joined for analysis

      22% had non-manifold geometry
Non-manifold edgesMore than two triangles meet along one edge. The inspector flags this junction for review.
Flagged for review

      16% had degenerate faces
Zero-area trianglesA collapsed triangle has no usable surface. YO3D removes zero-area and duplicate triangles when reading the file.
Removed on import

      26% had multiple components
Disconnected partsSeparate groups of triangles can be intentional in a multi-part model or leftover geometry. YO3D counts them but keeps them.
Counted, kept

    

Sources: Thingi10K dataset summary and Zhou and Jacobson, 2016.

Your model stays on your device.

The inspector reads, checks and previews changes in your browser. It does not upload your model. If you join the pilot, the form sends your email and the answers you choose to submit.

Fig. 3Model-file handling during inspection

Passing mesh checks doesn’t guarantee a successful print.

What mesh checks can tell youThey check how triangles connect and face. They can’t assess strength, fit, wall thickness or printer settings.
Review each repairFilling a hole adds new faces. Compare the repaired copy with the original before exporting.
Review the sliced previewSupports, overhangs and thin walls depend on your printer, material and settings. Check the slice before printing.

Pilot

Tell us which mesh problems to solve next.

We’re exploring batch checks, ways to find surfaces that cross through themselves, and warnings for walls that may be too thin to print. These features aren’t available in this prototype yet. Tell us which model-file problems cost you the most time.

Early access to each repair stage as it ships
A direct line to tell us which files break
Pilot pricing details before paid plans launch