Index: src/frames.hpp
===================================================================
--- src/frames.hpp	(revision 29858)
+++ src/frames.hpp	(working copy)
@@ -387,6 +387,9 @@
     //!  (-PI <= alfa <= PI)
     void GetEulerZYZ(double& alfa,double& beta,double& gamma) const;

+    //! Sets the value of this object to a rotation specified with Quaternion convention
+    //! the norm of (x,y,z,w) should be equal to 1
+    static Rotation Quaternion(double x,double y,double z, double w);

     //! Sets the value of this object to a rotation specified with RPY convention:
     //! first rotate around X with roll, then around the
Index: src/frames.cpp
===================================================================
--- src/frames.cpp	(revision 29858)
+++ src/frames.cpp	(working copy)
@@ -178,6 +178,14 @@

 }

+Rotation Rotation::Quaternion(double x,double y,double z, double w)
+{
+  double x2, y2, z2, w2;
+  x2 = x*x;  y2 = y*y; z2 = z*z;  w2 = w*w;
+  return Rotation(w2+x2-y2-z2, 2*x*y-2*w*z, 2*x*z+2*w*y,
+		  2*x*y+2*w*z, w2-x2+y2-z2, 2*y*z-2*w*x,
+		  2*x*z-2*w*y, 2*y*z+2*w*x, w2-x2-y2+z2);
+}

 Rotation Rotation::RPY(double roll,double pitch,double yaw)
     {