Fix #1386: geometry generation fails when creating a new CPACS file from the simpletest.cpacs.xml template

[joergbrech]

Description

Fixes #1386.

Opening the TIGLCreator template TIGLCreator/data/templates/simpletest.cpacs.xml failed to generate geometry after #1367 switched the template's fuselage "Circle" profile from a pointList to a standardProfile/rectangle (heightToWidthRatio=1, cornerRadius=0.5).

That combination is the degenerate limit where a rounded rectangle becomes a pure circle: all four straight edges of the rectangle collapse to zero length. BuildWireRectangle (src/common/tiglcommonfunctions.cpp) didn't special-case this, so it still built a zero-length line segment for each straight edge and fed it into CTiglBSplineAlgorithms::concatCurves alongside the four quarter-circle arcs. Concatenating those degenerate segments produced knots that ended up closer together than OpenCASCADE's internal tolerance, and OCCT throws Standard_Failure: BSpline curve: Knots interval values too close.

Fix: BuildWireRectangle now skips adding a straight edge whenever its two endpoints coincide, instead of feeding a zero-length segment through the interpolation/concatenation pipeline. At the circle limit this correctly reduces to a wire built purely from the four quarter-circle arcs.

Finally, the scaling of the fuselage had to be adapted to obtain the same Sodacan-geometry we are all accustomed to. With the standard profile the radius was decreased.

This PR was co-authored with Claude Code and thoroughly checked by me.

How Has This Been Tested?

• Added TiglCommonFunctions.BuildWireRectangle_FullCircleLimit in tests/unittests/tiglCommonFunctions.cpp, which reproduces the exact degenerate input (heightToWidthRatio=1, cornerRadius=0.5) used by the template. Before the fix this test throws Standard_Failure: BSpline curve: Knots interval values too close; after the fix it builds a valid, closed wire and lofts successfully.
• Verified end-to-end by opening TIGLCreator/data/templates/simpletest.cpacs.xml directly and building both the fuselage and wing lofts — both now produce valid geometry (BRepCheck_Analyzer(...).IsValid()).
• Ran the full unit test suite (pixi run -e default unittests): all 899 tests pass, no regressions (including the existing FuselageStandardProfile.* and TiglCommonFunctions.BuildWireRectangle_* cases covering non-degenerate rectangle/rounded-rectangle profiles).

Screenshots, that help to understand the changes(if applicabl

N/A (non-visual fix in geometry construction code).

Checklist for PR Author:

• Unit or integration test added (if applicable)
• Python interface updated (if applicable)
• Python test added (if Python interface updated)
• Doxygen docstrings added
• ChangeLog.md updated

[github-actions]

PR Reminders

This PR has changes in src/, TIGLCreator/, and tests/unittests/ but not in tests/integrationtests/, tests/python/, or bindings/python_internal/. ChangeLog.md has changes.

• 💡 Tip: Please check if new classes need to be added to the Python bindings

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.21%. Comparing base (2dc512d) to head (c3c8f83).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1387      +/-   ##
==========================================
- Coverage   73.22%   73.21%   -0.02%     
==========================================
  Files         324      324              
  Lines       28567    28556      -11     
==========================================
- Hits        20919    20908      -11     
  Misses       7648     7648              

Flag	Coverage Δ
unittests	73.21% <100.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/common/tiglcommonfunctions.cpp	78.31% <100.00%> (-0.21%)	⬇️

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[svengoldberg]

Looks good and also like an elegant solution to me!

Just a small annotation here, although it does not belong to the present changes