From 63d86e00e1e6a482fcad527ae0b883deccceed11 Mon Sep 17 00:00:00 2001
From: azv <azv@opencascade.com>
Date: Tue, 28 Jul 2020 18:48:16 +0300
Subject: [PATCH] Issue #3279: Incorrect result of 1D-Fillet with boundary
 value of radius

Additional check if the fillet edge eats the original edges.
---
 src/GeomAlgoAPI/GeomAlgoAPI_Fillet1D.cpp | 16 +++++++++++-----
 src/GeomAlgoImpl/GEOMImpl_Fillet1d.cxx   |  8 ++++++++
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/src/GeomAlgoAPI/GeomAlgoAPI_Fillet1D.cpp b/src/GeomAlgoAPI/GeomAlgoAPI_Fillet1D.cpp
index 440822088..e937beab9 100644
--- a/src/GeomAlgoAPI/GeomAlgoAPI_Fillet1D.cpp
+++ b/src/GeomAlgoAPI/GeomAlgoAPI_Fillet1D.cpp
@@ -110,15 +110,21 @@ void GeomAlgoAPI_Fillet1D::build(const GeomShapePtr& theBaseWire,
 
     // create fillet builder
     GEOMImpl_Fillet1d aFilletBuilder(anEdge1, anEdge2, aPlane->impl<gp_Pln>());
-    if (!aFilletBuilder.Perform(theRadius)) {
-      // store the failed vertex and continue
+    bool isOk = aFilletBuilder.Perform(theRadius);
+    TopoDS_Edge aFilletEdge;
+    if (isOk) {
+      GeomPointPtr aPoint = aVE->first->vertex()->point();
+      aFilletEdge = aFilletBuilder.Result(aPoint->impl<gp_Pnt>(), anEdge1, anEdge2);
+      isOk = !aFilletEdge.IsNull();
+    }
+
+    if (!isOk) {
+      // something gone wrong and the fillet edge is not constructed,
+      // just store the failed vertex and continue
       myFailedVertices.push_back(*aVIt);
       continue;
     }
 
-    GeomPointPtr aPoint = aVE->first->vertex()->point();
-    TopoDS_Edge aFilletEdge = aFilletBuilder.Result(aPoint->impl<gp_Pnt>(), anEdge1, anEdge2);
-
     // store modified shapes
     myGenerated[aVE->first].push_back(convert(aFilletEdge));
     SetOfShapes::const_iterator aEIt = aVE->second.begin();
diff --git a/src/GeomAlgoImpl/GEOMImpl_Fillet1d.cxx b/src/GeomAlgoImpl/GEOMImpl_Fillet1d.cxx
index 6ed7b3eac..3f3c2d74e 100644
--- a/src/GeomAlgoImpl/GEOMImpl_Fillet1d.cxx
+++ b/src/GeomAlgoImpl/GEOMImpl_Fillet1d.cxx
@@ -664,6 +664,10 @@ TopoDS_Edge GEOMImpl_Fillet1d::Result(const gp_Pnt& thePoint,
       else
         theEdge1 = aDivider1.Edge();
   }
+  else {
+    // error: filleted edge becomes degenerated
+    aResult = TopoDS_Edge();
+  }
 
   aCurve = BRep_Tool::Curve(myEdge2, aStart, anEnd);
   aCurve->D1(aNearest->GetParam2(), aPoint2, aDir);
@@ -682,6 +686,10 @@ TopoDS_Edge GEOMImpl_Fillet1d::Result(const gp_Pnt& thePoint,
       else
         theEdge2 = aDivider2.Edge();
   }
+  else {
+    // error: filleted edge becomes degenerated
+    aResult = TopoDS_Edge();
+  }
 
   delete aNearest;
   return aResult;
-- 
2.39.2