OCCT (Open-Cascade-SAS) errors

6 recurring problems engineers report in OCCT (Open-Cascade-SAS), ranked by impact.

#76 by errors trackedMCAD

Recurring OCCT (Open-Cascade-SAS) errors, by impact

  1. 1A guided pipe sweep that OCCT 7.9.3 builds exactly comes out the wrong volume in 8.0.1, thinner than spec near the ends. Tighter tolerance made it worse: 0.937 thick vs 1.MCAD · Agent failure · 1 report74
  2. 2Fusing a solid with a copy of itself returns zero solids and zero volume, with IsDone true, no errors or warnings, and the empty result passes BRepCheck_Analyzer, while the input is 3296 mm3, and fusing the same instance with itself works.MCAD · Agent failure · 1 report74
  3. 3STEP export writes material density as g^3 cm^2 with an untyped value. OCCT's reader ignores the exponents, so OCCT round-trips with itself fine, and other readers reject or misread the file.MCAD · Agent failure · 1 report74
  4. 4When a STEP file declares uncertainty over about 6.283 mm (2 pi), a cone ending in an apex reads back wrong, invalid solid or zero-area conical face, with no error or warning from the reader.MCAD · Agent failure · 1 report74
  5. 5On long helical thread flanks, intersection tolerance grew from 3e-6 to 1.45e-4, cutting a threaded cylinder failed at 7 of 12 phases, and two more phases returned a valid solid about 60 mm3 too heavy.MCAD · Agent failure · 1 report66
  6. 6FreeCAD's STEP export writes non-ASCII part labels as raw UTF-8, now filed upstream with OCCT.MCAD · Agent failure · 1 report58

How it fails

  1. Agent failure6

Engineering tools that address these errors

Sourced from public community reports. Costs and delays on individual entries are modeled estimates, not measurements.