Why does an upright cube report zero overhang area?

Its bottom face is on the assumed bed plane and is reported as bed contact, while its side walls are vertical. The top face points upward and is not an overhang.

Why is there a winding warning?

Overhang direction depends on outward triangle normals. If winding is inconsistent or inverted, the report may classify faces incorrectly; run Unify normals and check the mesh topology.

Does the report include supports or bridges?

No. It measures downward surface area only. Support projection, bridging, and material-specific sagging are slicer decisions.

What happens on very large meshes?

Overhang area is still measured, but the manifold/orientation check is skipped above 2,000,000 triangles and the report says so.

Print readiness/Checks

3D print overhang checker (local)

Q: Is the angle measured from the bed or from vertical?

From vertical. A vertical wall is 0°, a 45-degree slope is 45°, and a horizontal downward ceiling is 90°.

Measure downward-facing overhang area without uploading the model. The Worker welds and cleans the mesh, measures each downward triangle by its angle from vertical, excludes faces resting on the assumed bed plane, and reports the area at a threshold you control.

ReadyNo uploadWorkerSTL · OBJ · PLY · 3MF · GLB · glTF

Tool facts

Formats: STL · OBJ · PLY · 3MF · GLB · glTF
Output: Report
Worker: Yes
Max file: 500 MB
Runs: in your browser

Why local

Overhang report

No upload

Overhang report

The mesh is welded and cleaned before analysis. Downward faces are measured from vertical; faces on the lowest model plane count as bed contact, not overhangs. This is a face-level estimate—supports, bridges, and slicer behavior can differ.

Drop a model to check overhangs

STL, OBJ, PLY, 3MF, GLB, or a self-contained glTF. Downward faces are measured by angle from vertical; the lowest model plane is treated as the bed.

STL · OBJ · PLY · 3MF · GLB · GLTF · Threshold (degrees from vertical)

Drop a model to check overhangs

STL, OBJ, PLY, 3MF, GLB, or a self-contained glTF. Downward faces are measured by angle from vertical; the lowest model plane is treated as the bed.

Choose a file

Max file size: 500 MB · No upload

Threshold (degrees from vertical)

Faces at or above this angle count as overhangs. A vertical wall is 0°; a horizontal ceiling is 90°.

No upload · File.slice() / ArrayBuffer → Worker → overhang histogram.

How it works

1
Drop an STL, OBJ, PLY, 3MF, GLB, or self-contained glTF file.
2
The Worker welds vertices, removes degenerate triangles, and reads the bounding box.
3
Each downward-facing triangle is measured by angle from vertical; the lowest model plane is treated as the bed.
4
Faces at or above the selected threshold are summed and compared with the total surface area.
5
Adjust the threshold to see the area distribution by 15-degree bands without reparsing the file.

What the numbers mean

Angle

Angle is measured from vertical: a vertical wall is 0°, a 45-degree slope is 45°, and a horizontal downward ceiling is 90°. Only downward-facing triangles are counted.

Threshold

The threshold includes faces at or above the chosen angle. A lower threshold catches more steep surfaces; a higher threshold focuses on nearly horizontal ceilings.

Bed contact

Downward faces lying on the lowest model plane are treated as bed contact and excluded from overhang area. This assumes the model is placed with its lowest point on the build plate.

Limits

This is a face-level geometric estimate. It does not project supports, detect bridges, test self-intersections, or predict a slicer's exact support placement; verify in your slicer before printing.

Printing notes

A 45-degree threshold is a common starting point, but the best angle depends on material, cooling, layer height, and printer.
Rotate the model or add chamfers to turn steep downward faces into self-supporting slopes.
If the orientation warning appears, run Unify normals first; inward or inconsistent winding reverses the measured direction.
Bridges are not the same as overhangs. Check the slicer preview for spans between supports.

Questions

References

· ISO/ASTM 52900
· FDM support generation: overhang angle and self-supporting slopes