diff --git a/src/ODE/sixDOF/finiteRotation/finiteRotation.C b/src/ODE/sixDOF/finiteRotation/finiteRotation.C
index 645724186..e52542116 100644
--- a/src/ODE/sixDOF/finiteRotation/finiteRotation.C
+++ b/src/ODE/sixDOF/finiteRotation/finiteRotation.C
@@ -26,7 +26,8 @@ Class
 
 Author
     Dubravko Matijasevic, FSB Zagreb.  All rights reserved.
-    Update by Hrvoje Jasak
+    Hrvoje Jasak, FSB Zagreb.  All rights reserved.
+    Vuko Vukcevic, FSB Zagreb.  All rights reserved.
 
 \*---------------------------------------------------------------------------*/
 
@@ -82,9 +83,8 @@ Foam::vector Foam::finiteRotation::eulerAngles(const tensor& rotT)
     // Calculate roll angle
     rollAngle = atan2(rotT.yz(), rotT.zz());
 
-    // Use mag to avoid negative value due to round-off
-    // HJ, 24/Feb/2016
-    // Bugfix: sqr. SS, 18/Apr/2016
+    // Use mag to avoid negative value due to round-off, HJ, 24/Feb/2016
+    // Bugfix: missing sqr. SS, 18/Apr/2016
     const scalar c2 = sqrt(sqr(rotT.xx()) + sqr(rotT.xy()));
 
     // Calculate pitch angle
@@ -122,6 +122,14 @@ Foam::finiteRotation::finiteRotation
 {}
 
 
+Foam::finiteRotation::finiteRotation(const tensor& R)
+:
+    eInitial_(R),
+    rotTensor_(R),
+    rotIncrementTensor_(tensor::zero)
+{}
+
+
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
 Foam::finiteRotation::~finiteRotation()
@@ -130,12 +138,23 @@ Foam::finiteRotation::~finiteRotation()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+void Foam::finiteRotation::updateRotation(const tensor& R)
+{
+    rotIncrementTensor_ = (R & rotTensor_.T());
+    rotTensor_ = R;
+}
+
+
 void Foam::finiteRotation::updateRotation(const HamiltonRodriguezRot& rot)
 {
-    tensor rotR = rot.R();
+    updateRotation(rot.R());
+}
 
-    rotIncrementTensor_ = (rotR & (rotTensor_.T()));
-    rotTensor_ = rotR;
+
+void Foam::finiteRotation::updateRotationGivenIncrement(const tensor& incR)
+{
+    rotIncrementTensor_ = incR;
+    rotTensor_ = (incR & rotTensor_);
 }
 
 
diff --git a/src/ODE/sixDOF/finiteRotation/finiteRotation.H b/src/ODE/sixDOF/finiteRotation/finiteRotation.H
index 8d3f97822..cf496f375 100644
--- a/src/ODE/sixDOF/finiteRotation/finiteRotation.H
+++ b/src/ODE/sixDOF/finiteRotation/finiteRotation.H
@@ -26,7 +26,8 @@ Class
 
 Author
     Dubravko Matijasevic, FSB Zagreb.  All rights reserved.
-    Updated by Hrvoje Jasak
+    Hrvoje Jasak, FSB Zagreb.  All rights reserved.
+    Vuko Vukcevic, FSB Zagreb.  All rights reserved.
 
 SourceFiles
     finiteRotation.C
@@ -89,6 +90,9 @@ public:
             const scalar& angle
         );
 
+        //- Construct from rotation tensor
+        explicit finiteRotation(const tensor& R);
+
 
     // Destructor
 
@@ -97,9 +101,15 @@ public:
 
     // Member Functions
 
-        //- Update rotation
+        //- Update rotation given rotation tensor
+        void updateRotation(const tensor& R);
+
+        //- Update rotation given HamiltonRodriguezRot (quaternions)
         void updateRotation(const HamiltonRodriguezRot& rot);
 
+        //- Update rotation given increment rotation tensor
+        void updateRotationGivenIncrement(const tensor& incR);
+
         //- Return initial quaternions
         const HamiltonRodriguezRot& eInitial() const;
 
diff --git a/src/ODE/sixDOF/quaternions/HamiltonRodriguezRot.H b/src/ODE/sixDOF/quaternions/HamiltonRodriguezRot.H
index a09ca6616..55f7f129b 100644
--- a/src/ODE/sixDOF/quaternions/HamiltonRodriguezRot.H
+++ b/src/ODE/sixDOF/quaternions/HamiltonRodriguezRot.H
@@ -26,7 +26,8 @@ Class
 
 Author
     Dubravko Matijasevic, FSB Zagreb.  All rights reserved.
-    Updated by Hrvoje Jasak
+    Hrvoje Jasak, FSB Zagreb.  All rights reserved.
+    Vuko Vukcevic, FSB Zagreb.  All rights reserved.
 
 Description
     Rotation defined with 4 parameters: quaternions.
@@ -66,13 +67,13 @@ class HamiltonRodriguezRot
         scalarRectangularMatrix Gt_;
 
         //- Inertial to rotated coordinate system transformation
-        mutable tensor R_;
+        tensor R_;
 
 
     // Private member functions
 
         //- Calculate R_ - inertial to body coord. sys. rotation
-        inline void calculateR() const
+        inline void calculateR()
         {
             R_.xx() = 2*(e1_*e1_ + e0_*e0_ - 0.5);
             R_.xy() = 2*(e1_*e2_ + e0_*e3_);
@@ -133,11 +134,7 @@ public:
         }
 
         //- Construct from rotation vector and angle
-        explicit HamiltonRodriguezRot
-        (
-            const vector& rVect,
-            const scalar& rAngle
-        )
+        HamiltonRodriguezRot(const vector& rVect, const scalar& rAngle)
         :
             Gt_(4, 3),
             R_(tensor::zero)
@@ -164,6 +161,29 @@ public:
             calculateGt();
         }
 
+        //- Construct from rotation tensor
+        explicit HamiltonRodriguezRot(const tensor& R)
+        :
+            Gt_(4, 3),
+            R_(R)
+        {
+            // Calculate Hamilton - Rodriguez (Euler) parameters from rotation
+            // matrix
+
+            // Note: sign of e0_ assumed positive
+            e0_ = Foam::sqrt((tr(R) + 1.0)/4.0);
+
+            // Helper variable
+            const scalar oneByFourEo = 1.0/(4.0*e0_);
+
+            e1_ = oneByFourEo*(R.zy() - R.yz());
+            e2_ = oneByFourEo*(R.xz() - R.zx());
+            e3_ = oneByFourEo*(R.yx() - R.xy());
+
+            // Calculate Gt
+            calculateGt();
+        }
+
 
     // Destructor