diff --git a/src/Mod/Sketcher/App/Constraint.h b/src/Mod/Sketcher/App/Constraint.h
index a57119606f..40a46dd502 100644
--- a/src/Mod/Sketcher/App/Constraint.h
+++ b/src/Mod/Sketcher/App/Constraint.h
@@ -68,7 +68,8 @@ enum InternalAlignmentType {
     HyperbolaMinor          = 6,
     HyperbolaFocus          = 7,
     ParabolaFocus           = 8,
-    BSplineControlPoint     = 9 // in this constraint "Third" is used to indicate the index of the control point (0-poles), it is not a GeoId
+    BSplineControlPoint     = 9,
+    BSplineKnotPoint        = 10,
 };
 
 /// define if you want to use the end or start point
diff --git a/src/Mod/Sketcher/App/Sketch.cpp b/src/Mod/Sketcher/App/Sketch.cpp
index 77f9c66cbf..068dbd68ca 100644
--- a/src/Mod/Sketcher/App/Sketch.cpp
+++ b/src/Mod/Sketcher/App/Sketch.cpp
@@ -1244,6 +1244,8 @@ int Sketch::addConstraint(const Constraint *constraint)
                 break;
             case BSplineControlPoint:
                 rtn = addInternalAlignmentBSplineControlPoint(constraint->First,constraint->Second, constraint->InternalAlignmentIndex);
+            case BSplineKnotPoint:
+                rtn = addInternalAlignmentKnotPoint(constraint->First,constraint->Second, constraint->InternalAlignmentIndex);
             default:
                 break;
         }
@@ -2469,6 +2471,32 @@ int Sketch::addInternalAlignmentBSplineControlPoint(int geoId1, int geoId2, int
     return -1;
 }
 
+int Sketch::addInternalAlignmentKnotPoint(int geoId1, int geoId2, int knotindex)
+{
+    std::swap(geoId1, geoId2);
+
+    geoId1 = checkGeoId(geoId1);
+    geoId2 = checkGeoId(geoId2);
+
+    if (Geoms[geoId1].type != BSpline)
+        return -1;
+    if (Geoms[geoId2].type != Point)
+        return -1;
+
+    int pointId1 = getPointId(geoId2, start);
+
+    if (pointId1 >= 0 && pointId1 < int(Points.size())) {
+        GCS::Point &p = Points[pointId1];
+
+        GCS::BSpline &b = BSplines[Geoms[geoId1].index];
+
+        int tag = ++ConstraintsCounter;
+        GCSsys.addConstraintInternalAlignmentBSplineKnot(b, p, knotindex, tag);
+        return ConstraintsCounter;
+    }
+    return -1;
+}
+
 double Sketch::calculateAngleViaPoint(int geoId1, int geoId2, double px, double py)
 {
     geoId1 = checkGeoId(geoId1);
diff --git a/src/Mod/Sketcher/App/Sketch.h b/src/Mod/Sketcher/App/Sketch.h
index 8ddaa02108..9f29c29d93 100644
--- a/src/Mod/Sketcher/App/Sketch.h
+++ b/src/Mod/Sketcher/App/Sketch.h
@@ -315,6 +315,7 @@ public:
     int addInternalAlignmentHyperbolaFocus(int geoId1, int geoId2);
     int addInternalAlignmentParabolaFocus(int geoId1, int geoId2);
     int addInternalAlignmentBSplineControlPoint(int geoId1, int geoId2, int poleindex);
+    int addInternalAlignmentKnotPoint(int geoId1, int geoId2, int knotindex);
     //@}
 public:
     //This func is to be used during angle-via-point constraint creation. It calculates
diff --git a/src/Mod/Sketcher/App/planegcs/GCS.cpp b/src/Mod/Sketcher/App/planegcs/GCS.cpp
index 3272e882cc..6889b0a7ac 100644
--- a/src/Mod/Sketcher/App/planegcs/GCS.cpp
+++ b/src/Mod/Sketcher/App/planegcs/GCS.cpp
@@ -1014,6 +1014,12 @@ int System::addConstraintInternalAlignmentBSplineControlPoint(BSpline &b, Circle
     return addConstraintEqual(b.weights[poleindex], c.rad, tagId);
 }
 
+int System::addConstraintInternalAlignmentBSplineKnot(BSpline &b, Point &p, int knotindex, int tagId)
+{
+    // not yet implemented
+    return 0;
+    
+}
 
 //calculates angle between two curves at point of their intersection p. If two
 //points are supplied, p is used for first curve and p2 for second, yielding a
diff --git a/src/Mod/Sketcher/App/planegcs/GCS.h b/src/Mod/Sketcher/App/planegcs/GCS.h
index 193cfb08ee..8ed134161c 100644
--- a/src/Mod/Sketcher/App/planegcs/GCS.h
+++ b/src/Mod/Sketcher/App/planegcs/GCS.h
@@ -234,6 +234,7 @@ namespace GCS
         int addConstraintInternalAlignmentHyperbolaFocus(Hyperbola &e, Point &p1, int tagId=0);
         int addConstraintInternalAlignmentParabolaFocus(Parabola &e, Point &p1, int tagId=0);
         int addConstraintInternalAlignmentBSplineControlPoint(BSpline &b, Circle &c, int poleindex, int tag=0);
+        int addConstraintInternalAlignmentBSplineKnot(BSpline &b, Point &p, int knotindex, int tagId=0);
 
         double calculateAngleViaPoint(Curve &crv1, Curve &crv2, Point &p);
         double calculateAngleViaPoint(Curve &crv1, Curve &crv2, Point &p1, Point &p2);