FreeCAD Part Check Geometry Tool to Verify if geometry is a Valid Solid.

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In FreeCAD, the “Check Geometry” tool (also called “Part → Check Geometry”) is used to analyze and validate 3D shapes for errors like non-manifold edges, self-intersections, or invalid topology. This is especially useful before performing Boolean operations (Union, Cut, Common) or exporting to other formats (STEP, STL).

How to Use Check Geometry in FreeCAD-:

  1. Select the Object

    • In the Model Tree or 3D View, select the object you want to check (e.g., a Part or PartDesign Body).

  2. Run the Check Geometry Tool

    • Go to the Part Workbench.

    • Click Part → Check Geometry (or find it in the toolbar).

  1. Review the Results-:

    • dialog box will appear showing any errors or warnings.

    • Expand the “Issues” section to see details like:

      • Self-intersections (invalid for Booleans)

      • Non-manifold edges (edges shared by more than two faces)

      • Invalid faces or edges (degenerate geometry)

  2. Fix Issues (If Found)-:

    • Refine the shape (Part → Refine Shape).

    • Use “Part → Shape Builder” to repair gaps.

    • Remodel problematic areas manually.

Common Errors & Fixes-:

Error Type Possible Fix
Self-intersections Use Part → Refine Shape or remodel the intersecting area.
Non-manifold edges Ensure no extra edges/faces exist; use Part → Explode Compound to inspect.
Missing/Invalid faces Check for gaps in sketches; rebuild the extrusion.
“Not a solid” error Ensure the shape is watertight (no holes); use Part → Convert to Solid.

Additional Tips-:

  • Use “Part → Validate Shape” for deeper analysis (available in Python console via Shape.check()).

  • For STL exports, ensure the mesh is error-free (Mesh → Analyze → Evaluate & Repair).

  • Boolean operations fail? Check geometry first, then try Part → Defeaturing to remove problematic edges.

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Amar Patel
About Amar Patel 259 Articles
Hi, I am Amar Patel from India. Founder, Author and Administrator of mechnexus.com. I am a Simple Average Man who Loves life and Love living life. Professionally I am a Mechanical Engineer with Solid command over CAD software like FreeCAD, SolidWorks, Autodesk Inventor and AutoCAD Mechanical. I’m here to share my knowledge to help you accomplish your design and engineering tasks quicker and easier. I am Passionate about learning new things especially about Open-Source Software. I love teaching therefore I started my YouTube Channel on FreeCAD and I believe FreeCAD have lots of potential than traditional 3D software. contact me - [email protected]