STL Wall Thickness Checker (Thin-Wall Heat Map)

See STL Wall Thickness Checker (Thin-Wall Heat Map) in action

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1Drop in your model and set the file units.

2Choose your printing process or a custom minimum.

3Press Check wall thickness.

Free STL Wall Thickness Checker for 3D Printing

Thin walls are one of the top reasons prints fail: they vanish in the slicer, break on removal, or print as a single weak line. This checker casts a ray from every surface triangle into the material and measures the distance to the opposite wall, then colours the model: red where the wall is thinner than your limit, orange up to twice the limit and green where it is comfortably thick.

Choose a preset for your process — FDM 0.4 mm nozzle (0.8 mm), 0.6 mm nozzle, resin, SLS, metal or a strong-part setting — or type any minimum. The tool reports the thinnest wall, typical thickness, the percentage of surface below your limit and how long it took, using a bounding-volume hierarchy so even large meshes finish in seconds.

Key features

How to use it

1. Drop in your model and set the file units.
2. Choose your printing process or a custom minimum.
3. Press Check wall thickness.
4. Thicken the red regions in your CAD program and re-check.

Worked example

Example

A 16 mm bore through a 20 mm diameter tube leaves a 2 mm wall. Checked against an FDM minimum of 0.8 mm the whole surface is green; against a 2.5 mm strong-part minimum the walls turn red.

Who uses this tool

Tips for the best results

• The minimum wall is usually 2 × nozzle width for FDM.
• Run the repair tool first so normals point outward.
• Use Thorough detail for small parts.
• Red at sharp corners is common and often harmless — look at the whole area.

Common mistakes to avoid

• Trusting the result on an open or inverted mesh.
• Using the wrong units.
• Treating ray-based thickness as a certified measurement.

Frequently asked questions