A SMALL MESH DIAGNOSTICS LAB
Four original examples for learning what an edge report means. Download a file for your own software or open it in the free browser checker.
Published 12 October 2026 · By MeshRebuild · No account required
Choose millimetres in the checker to use the dimensions below. STL itself has no stored physical unit. These deliberately simple files use exact matching vertex coordinates; another program may classify or merge edges differently. A clean edge count does not test self-intersections, wall thickness, or printability.
Understand boundary and non-manifold edges →EXAMPLE 01 / ASCII STL
A cube with twelve outward-oriented triangles. Choose millimetres to interpret it as 20 × 20 × 20 mm. A clean edge result does not certify printability.
EXAMPLE 02 / ASCII STL
The same cube with its two top-face triangles removed. Its open rim creates four boundary edges. It is an intentional diagnostic example, not a printable part.
EXAMPLE 03 / ASCII STL
One triangle has reversed vertex order. All edges still have two incident faces, but three shared edges have inconsistent orientation. This illustrates why a closed surface alone is insufficient.
EXAMPLE 04 / ASCII STL
Three triangles share one edge, producing one non-manifold edge and six outer boundary edges. This deliberately open surface is a teaching fixture, not a finished solid.
You may use, modify and redistribute these original MeshRebuild test files, including in workshops and documentation. Attribution is appreciated but optional. The broken examples demonstrate diagnostics and are not production parts.
Download the usage note →A warning count is a starting point. Locate a defect in a mesh editor, preserve the original, and compare the required geometry after any repair.
Diagnose walls missing in the slicer →