CAM: Fix finish passes by avoiding fuzzy in Area.cpp (#19525)

src/Mod/CAM/App/Area.cpp

@@ -74,6 +74,7 @@
 #include <Base/Exception.h>
 #include <Mod/Part/App/CrossSection.h>
 #include <Mod/Part/App/FaceMakerBullseye.h>
+#include <Mod/Part/App/FuzzyHelper.h>
 #include <Mod/Part/App/PartFeature.h>
 #include <Mod/CAM/App/PathSegmentWalker.h>
 #include <Mod/CAM/libarea/Area.h>
@@ -1920,7 +1921,13 @@ std::vector<shared_ptr<Area>> Area::makeSections(PARAM_ARGS(PARAM_FARG, AREA_PAR
                     showShape(xp.Current(), nullptr, "section_%u_shape", i);
                     std::list<TopoDS_Wire> wires;
                     Part::CrossSection section(a, b, c, xp.Current());
-                    wires = section.slice(-d);
+                    Part::FuzzyHelper::withBooleanFuzzy(.0, [&]() {
+                        // Workaround for https://github.com/FreeCAD/FreeCAD/issues/17748
+                        // needed to make finish pass work.
+                        // This fix might be better to move into Part::CrossSection but it is kept
+                        // here for now to be on the safe side.
+                        wires = section.slice(-d);
+                    });
                     showShapes(wires, nullptr, "section_%u_wire", i);
                     if (wires.empty()) {
                         AREA_LOG("Section returns no wires");

src/Mod/Part/App/FuzzyHelper.cpp

@@ -27,12 +27,21 @@
 
 using namespace Part;
 
-double FuzzyHelper::BooleanFuzzy = 1.0;
+namespace {
+    double BooleanFuzzy = 1.0;
+}
 
 double FuzzyHelper::getBooleanFuzzy() {
     return BooleanFuzzy;
 }
-void FuzzyHelper::setBooleanFuzzy(const double fuzzy) {
-    BooleanFuzzy = fuzzy;
+
+void FuzzyHelper::setBooleanFuzzy(const double base) {
+    BooleanFuzzy = base;
 }
 
+void FuzzyHelper::withBooleanFuzzy(double base, std::function<void()> func) {
+    double oldValue = getBooleanFuzzy();
+    setBooleanFuzzy(base);
+    func();
+    setBooleanFuzzy(oldValue);
+}

src/Mod/Part/App/FuzzyHelper.h

@@ -26,22 +26,20 @@
 #define PART_FUZZYHELPER_H
 
 #include <Mod/Part/PartGlobal.h>
+#include <functional>
 
 namespace Part
 {
 
 /**
- * @brief The FuzzyHelper class provides a static helper function to determine fuzzy value for a boolean operation
+ * @brief The FuzzyHelper provides helper functions to determine fuzzy value for a boolean operation
  */
-class PartExport FuzzyHelper
+namespace FuzzyHelper
 {
-public:
-    static double getBooleanFuzzy();
-    static void setBooleanFuzzy(const double base);
-private:
-    static double BooleanFuzzy;
-};
-
+    double PartExport getBooleanFuzzy();
+    void PartExport setBooleanFuzzy(double base);
+    void PartExport withBooleanFuzzy(double base, std::function<void()> func);
+}
 
 }