Fix surface orientation in quest::STEPReader
#1765
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−22
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jcs15c
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Arlie-Capps,
BradWhitlock,
gunney1,
kennyweiss and
rhornung67
jcs15c
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kennyweiss
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Jan 9, 2026
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kennyweiss
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Thanks @jcs15c for this bugfix!
BradWhitlock
approved these changes
Jan 9, 2026
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Summary
quest::STEPReaderwhich checks the orientation of input opencascade surfaces, and corrects them in theprimal::NURBSPatchand STL output.quest::StepFileProcessor::PatchProcessorto emphasize that the contained opencascade object stores face geometry decoupled from its topology.MeshClipper.cppTopological data structures in opencascade have an extra
TopAbs_Orientationflag which determines if the associated geometry object should be flipped within the face representation. If set toREVERSED, the orientation of the surface geometry needs to be reversed to be properly read as consistent with the rest of the shape.Flipped face geometry was previously handled for trimmed NURBS output using (comparatively slow) numerical integration along trimming curves, but was not properly handled for triangulated output. Now in both cases, this condition is checked directly by the flag.