[PD] Fix helix placement

src/Mod/PartDesign/App/FeatureHelix.cpp

@@ -377,7 +377,8 @@ TopoDS_Shape Helix::generateHelixPath(double breakAtTurn)
     bool turned = axisOffset < 0;
     // since the factor does not only change the radius but also the path position, we must shift its offset back
     // using the square of the factor
-    double startOffset = 10000.0 * std::fabs(baseVector * axisVector);
+    double noAngle = angle == 0. ? 1. : 0.; // alternative to the legacy use of an auxiliary path
+    double startOffset = 10000.0 * std::fabs(noAngle * (profileCenter * axisVector) - baseVector * axisVector);
 
     if (radius < Precision::Confusion()) {
         // in this case ensure that axis is not in the sketch plane

src/Mod/PartDesign/PartDesignTests/TestTopologicalNamingProblem.py

@@ -914,6 +914,7 @@ class TestTopologicalNamingProblem(unittest.TestCase):
         helix = self.Doc.addObject("PartDesign::SubtractiveHelix", "SubHelix")
         helix.Profile = sketch
         helix.ReferenceAxis = (self.Doc.getObject("Sketch"), ["V_Axis"])
+        helix.Reversed = True
         body.addObject(sketch)
         body.addObject(helix)
         self.Doc.recompute()