Inspect ASCII or binary STL files locally. Explore a 3D preview and check boundary edges, face winding, duplicate faces and degenerate triangles.
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Choose one ASCII or binary STL, up to 20 MiB and 100,000 triangles. All checks run locally. WebGL 2 is needed for the preview; inspection and report can work without it.
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Your model will appear here. WebGL 2 is required.
Drag to orbit · right-drag to pan · wheel/pinch to zoom. Focus the viewer: arrows orbit, Shift + arrows pan, +/− zoom, 0 fits. Use buttons for the same actions.
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Boundary edges have one incident nondegenerate face. Non-manifold edges have more than two. Winding checks find two-face edges traversed in the same direction; they do not establish outward normals. Duplicate faces ignore vertex order. Zero-area triangles are exactly collinear in parsed coordinates and are excluded from edges and components. Duplicate nondegenerate faces remain included in edge counts.
Vertices are matched by exact parsed coordinates, with no tolerance welding. ASCII positions may round to float32 in the shared parser. Near-coincident vertices can remain separate; near-zero areas are not classified as zero. Components connect through shared vertices, even at a single touching point. Source units are unspecified by STL; dimensions do not establish millimetres or inches.
These are basic diagnostics, not a repair or printability certificate. Self-intersections, non-manifold vertices, overlapping shells, internal cavities, wall thickness and outward orientation are not validated. No issues found does not guarantee a watertight or printable model. Keep your source and verify important meshes in a dedicated modelling or slicing application.
Your model never leaves your device. Parsing, geometry checks and preview rendering all run locally using self-hosted code. No account, uploads or stored file history are required.
No. Basic edge, duplicate-face, degeneracy and winding checks do not detect self-intersections, non-manifold vertices, overlapping shells or wall-thickness problems. No issues found is not a guarantee of printability.
STL does not specify physical units. Bounds and dimensions use the parsed source coordinates. Confirm the intended unit in your modelling or slicing software.
Vertices match only when parsed coordinates are exactly equal. ASCII values can round to float32 during parsing; there is no tolerance welding. Components connect through shared vertices of nondegenerate triangles. Degenerate faces are excluded from edges/components; duplicate nondegenerate faces remain included.
Geometry checks and the downloadable JSON report do not require WebGL. The interactive preview and view PNG require WebGL 2.
