From f9cff4c8a203c3e9cc573ea8360c862afe9d0f56 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Thu, 6 Dec 2012 13:21:10 +0100
Subject: [PATCH] Improved algorithm to detect intersections of rotation axis
 and sketch

---
 src/Mod/PartDesign/App/FeatureSketchBased.cpp | 76 ++++++++++++++++++-
 1 file changed, 75 insertions(+), 1 deletion(-)

diff --git a/src/Mod/PartDesign/App/FeatureSketchBased.cpp b/src/Mod/PartDesign/App/FeatureSketchBased.cpp
index 6d2fb9b3b..7ee871768 100644
--- a/src/Mod/PartDesign/App/FeatureSketchBased.cpp
+++ b/src/Mod/PartDesign/App/FeatureSketchBased.cpp
@@ -60,6 +60,9 @@
 # include <Standard_Version.hxx>
 #endif
 
+#include <BRepExtrema_DistShapeShape.hxx>
+#include <TopExp.hxx>
+#include <TopTools_IndexedDataMapOfShapeListOfShape.hxx>
 
 #include "FeatureSketchBased.h"
 #include <Mod/Part/App/Part2DObject.h>
@@ -538,7 +541,77 @@ const bool SketchBased::checkWireInsideFace(const TopoDS_Wire& wire, const TopoD
     return (proj.More() && proj.Current().Closed());
 }
 
-const bool SketchBased::checkLineCrossesFace(const gp_Lin &line, const TopoDS_Face &face) {
+const bool SketchBased::checkLineCrossesFace(const gp_Lin &line, const TopoDS_Face &face)
+{
+#if 1
+    BRepBuilderAPI_MakeEdge mkEdge(line);
+    TopoDS_Wire wire = ShapeAnalysis::OuterWire(face);
+    BRepExtrema_DistShapeShape distss(wire, mkEdge.Shape(), Precision::Confusion());
+    if (distss.IsDone()) {
+        // build up map vertex->edge
+        TopTools_IndexedDataMapOfShapeListOfShape vertex2Edge;
+        TopExp::MapShapesAndAncestors(wire, TopAbs_VERTEX, TopAbs_EDGE, vertex2Edge);
+
+        for (Standard_Integer i=1; i<= distss.NbSolution(); i++) {
+            BRepExtrema_SupportType type = distss.SupportTypeShape1(i);
+            if (type == BRepExtrema_IsOnEdge) {
+                //This further check is not really needed
+                return true;
+                //
+                TopoDS_Edge edge = TopoDS::Edge(distss.SupportOnShape1(i));
+                BRepAdaptor_Curve adapt(edge);
+                Standard_Real t;
+                distss.ParOnEdgeS1(i, t);
+                if (t > adapt.FirstParameter() && t < adapt.LastParameter()) {
+                    return true;
+                }
+            }
+            else if (type == BRepExtrema_IsVertex) {
+                // for a vertex check the two adjacent edges if there is a change of sign
+                TopoDS_Vertex vertex = TopoDS::Vertex(distss.SupportOnShape1(i));
+                const TopTools_ListOfShape& edges = vertex2Edge.FindFromKey(vertex);
+                if (edges.Extent() == 2) {
+                    // create a plane (pnt,dir) that goes through the intersection point and is built of
+                    // the vectors of the sketch normal and the rotation axis
+                    BRepAdaptor_Surface adapt(face);
+                    const gp_Dir& normal = adapt.Plane().Axis().Direction();
+                    gp_Dir dir = line.Direction().Crossed(normal);
+                    gp_Pnt pnt = distss.PointOnShape1(i);
+
+                    // from the first edge get a point next to the intersection point
+                    const TopoDS_Edge& edge1 = TopoDS::Edge(edges.First());
+                    BRepAdaptor_Curve adapt1(edge1);
+                    Standard_Real dist1 = adapt1.Value(adapt1.FirstParameter()).SquareDistance(pnt);
+                    Standard_Real dist2 = adapt1.Value(adapt1.LastParameter()).SquareDistance(pnt);
+                    gp_Pnt p_eps1;
+                    if (dist1 < dist2)
+                        p_eps1 = adapt1.Value(adapt1.FirstParameter() + 2*Precision::Confusion());
+                    else
+                        p_eps1 = adapt1.Value(adapt1.LastParameter() - 2*Precision::Confusion());
+
+                    // from the second edge get a point next to the intersection point
+                    const TopoDS_Edge& edge2 = TopoDS::Edge(edges.Last());
+                    BRepAdaptor_Curve adapt2(edge2);
+                    Standard_Real dist3 = adapt2.Value(adapt2.FirstParameter()).SquareDistance(pnt);
+                    Standard_Real dist4 = adapt2.Value(adapt2.LastParameter()).SquareDistance(pnt);
+                    gp_Pnt p_eps2;
+                    if (dist3 < dist4)
+                        p_eps2 = adapt2.Value(adapt2.FirstParameter() + 2*Precision::Confusion());
+                    else
+                        p_eps2 = adapt2.Value(adapt2.LastParameter() - 2*Precision::Confusion());
+
+                    // now check if we get a change in the sign of the distances
+                    Standard_Real dist_p_eps1_pnt = gp_Dir(gp_Vec(p_eps1, pnt)).Dot(dir);
+                    Standard_Real dist_p_eps2_pnt = gp_Dir(gp_Vec(p_eps2, pnt)).Dot(dir);
+                    if (dist_p_eps1_pnt * dist_p_eps2_pnt < 0)
+                        return true;
+                }
+            }
+        }
+    }
+
+    return false;
+#else
     // This is not as easy as it looks, because a distance of zero might be OK if
     // the axis touches the sketchshape in in a linear edge or a vertex
     // Note: This algorithm does not catch cases where the sketchshape touches the
@@ -595,6 +668,7 @@ const bool SketchBased::checkLineCrossesFace(const gp_Lin &line, const TopoDS_Fa
     }
 
     return false;
+#endif
 }
 
 void SketchBased::remapSupportShape(const TopoDS_Shape& newShape)