diff --git a/PlanarMechanics/Parts/FixedTranslation.mo b/PlanarMechanics/Parts/FixedTranslation.mo
index 2eda08e0..34c1d87a 100644
--- a/PlanarMechanics/Parts/FixedTranslation.mo
+++ b/PlanarMechanics/Parts/FixedTranslation.mo
@@ -7,7 +7,7 @@ model FixedTranslation "A fixed translation between two components (rigid rod)"
   final parameter SI.Length l = Modelica.Math.Vectors.length(r)
     "Length of vector r";
   SI.Position r0[2] "Length of the rod resolved w.r.t to inertal frame";
-  Real R[2,2] "Rotation matrix";
+  Real R[2,2] "Rotation matrix from world frame to frame_a";
 
   parameter Boolean animate = true "= true, if animation shall be enabled"
     annotation(Dialog(group="Animation"));
@@ -54,7 +54,7 @@ equation
   frame_a.fx + frame_b.fx = 0;
   frame_a.fy + frame_b.fy = 0;
 //  frame_a.t + frame_b.t - sx0*frame_b.fy + sy0*frame_b.fx = 0;
-  frame_a.t  + frame_b.t + r0*{frame_b.fy,-frame_b.fx} = 0;
+  frame_a.t + frame_b.t + r0*{frame_b.fy,-frame_b.fx} = 0;
   annotation (Icon(coordinateSystem(preserveAspectRatio=false, extent={{-100,-100},
             {100,100}}),
       graphics={
diff --git a/PlanarMechanics/Sources/RelativeForce.mo b/PlanarMechanics/Sources/RelativeForce.mo
index 42e4fdb4..bba6f14a 100644
--- a/PlanarMechanics/Sources/RelativeForce.mo
+++ b/PlanarMechanics/Sources/RelativeForce.mo
@@ -30,7 +30,7 @@ model RelativeForce "Input signal acting as force and torque on two frames"
   Modelica.Blocks.Interfaces.RealInput force[3]
     annotation (Placement(transformation(extent={{-20,-20},{20,20}}, origin={-60,-120}, rotation=90)));
 
-  Real R[2,2] "Rotation matrix";
+  Real R[2,2] "Rotation matrix from world frame to frame_b";
   SI.Angle phi "Rotation angle of the additional frame_c";
 
   Interfaces.Frame_resolve frame_resolve(fx = 0, fy = 0, t = 0, phi = phi) if resolveInFrame == Modelica.Mechanics.MultiBody.Types.ResolveInFrameAB.frame_resolve
diff --git a/PlanarMechanics/Sources/WorldForce.mo b/PlanarMechanics/Sources/WorldForce.mo
index f58e241c..040f504c 100644
--- a/PlanarMechanics/Sources/WorldForce.mo
+++ b/PlanarMechanics/Sources/WorldForce.mo
@@ -41,7 +41,7 @@ model WorldForce
     "Coordinate system in which vector is optionally resolved, if useExtraFrame is true"
     annotation (Placement(transformation(extent={{-16,-16},{16,16}},rotation=90,origin={0,-100})));
 
-  Real R[2,2] "Rotation matrix";
+  Real R[2,2] "Rotation matrix from world frame to frame_b";
   SI.Angle phi "Rotation angle of the additional frame_c";
 
 protected
@@ -76,7 +76,7 @@ equation
 
   R = {{cos(phi), -sin(phi)}, {sin(phi),cos(phi)}};
   {frame_b.fx,frame_b.fy} + R*{force[1], force[2]} = {0, 0};
-  frame_b.t +  force[3]= 0;
+  frame_b.t + force[3]= 0;
 
   annotation (
     Icon(