fix #865

[joergbrech]

fix #865

Description

This PR changes the tolerances used in the calls to CCPACSWingCell::CutChordWise and CCPACSWIngCell::CutSpanWise. These tolerances are used to check, wether a wing cell border lies on an isosurface of a single face (within the bounds defined by said tolerance). If yes, TiGL will trim the face to create the cell geometry. If no, TiGL will cut the face using expensive Boolean operations.

The consequence of a stricter tolerance is only that in more cases the Boolean operations will be used, increasing the calculation time and accuracy.

How Has This Been Tested?

I wouldn't know how to define a unit test of this. This has been tested with an internal CPACS file where the inaccuracies were evident in TiGLViewer.

Screenshots, that help to understand the changes(if applicable):

Checklist:

• A test for the new functionality was added.
• All tests run without failure.
• The new code complies with the TiGL style guide.
• New classes have been added to the Python interface.
• API changes were documented properly in tigl.h.

[codecov-commenter]

Codecov Report

Merging #866 (d1b5a0e) into master (a1af6b2) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master     #866   +/-   ##
=======================================
  Coverage   62.54%   62.54%           
=======================================
  Files         292      292           
  Lines       24636    24636           
=======================================
  Hits        15408    15408           
  Misses       9228     9228           

Impacted Files	Coverage Δ
src/engine_nacelle/CCPACSEnginePosition.h	50.00% <ø> (ø)
src/wing/CCPACSWingCell.cpp	21.44% <0.00%> (ø)