diff --git a/Modelica/Mechanics/MultiBody/Forces/Internal/BasicForce.mo b/Modelica/Mechanics/MultiBody/Forces/Internal/BasicForce.mo
index 0731015d7a..0f5e98576d 100644
--- a/Modelica/Mechanics/MultiBody/Forces/Internal/BasicForce.mo
+++ b/Modelica/Mechanics/MultiBody/Forces/Internal/BasicForce.mo
@@ -1,8 +1,9 @@
 within Modelica.Mechanics.MultiBody.Forces.Internal;
 model BasicForce
   "Force acting between two frames, defined by 3 input signals"
-  extends Modelica.Mechanics.MultiBody.Interfaces.PartialTwoFrames;
+  extends Interfaces.PartialForce;
   import Modelica.Mechanics.MultiBody.Types.ResolveInFrameAB;
+
   Interfaces.Frame_resolve frame_resolve
     "The input signals are optionally resolved in this frame"
     annotation (Placement(transformation(
@@ -22,36 +23,34 @@ model BasicForce
 
   SI.Position r_0[3]
     "Position vector from origin of frame_a to origin of frame_b resolved in world frame";
-  SI.Force f_b_0[3] "frame_b.f resolved in world frame";
+  SI.Force f_b_0[3] "Force frame_b.f resolved in world frame";
 
 equation
   assert(cardinality(frame_resolve) > 0, "Connector frame_resolve must be connected at least once and frame_resolve.r_0/.R must be set");
   frame_resolve.f = zeros(3);
   frame_resolve.t = zeros(3);
 
-   if resolveInFrame == ResolveInFrameAB.frame_a then
-      f_b_0     = -Frames.resolve1(frame_a.R, force);
-      frame_b.f =  Frames.resolve2(frame_b.R, f_b_0);
-   elseif resolveInFrame == ResolveInFrameAB.frame_b then
-      f_b_0     = -Frames.resolve1(frame_b.R, force);
-      frame_b.f = -force;
-   elseif resolveInFrame == ResolveInFrameAB.world then
-      f_b_0     = -force;
-      frame_b.f =  Frames.resolve2(frame_b.R, f_b_0);
-   elseif resolveInFrame == ResolveInFrameAB.frame_resolve then
-      f_b_0     = -Frames.resolve1(frame_resolve.R, force);
-      frame_b.f = Frames.resolve2(frame_b.R, f_b_0);
-   else
-      assert(false, "Wrong value for parameter resolveInFrame");
-      f_b_0     = zeros(3);
-      frame_b.f = zeros(3);
-   end if;
-   frame_b.t = zeros(3);
+  r_0 = frame_b.r_0 - frame_a.r_0;
+  frame_b.t = zeros(3);
+
+  if resolveInFrame == ResolveInFrameAB.frame_a then
+    f_b_0     = -Frames.resolve1(frame_a.R, force);
+    frame_b.f =  Frames.resolve2(frame_b.R, f_b_0);
+  elseif resolveInFrame == ResolveInFrameAB.frame_b then
+    f_b_0     = -Frames.resolve1(frame_b.R, force);
+    frame_b.f = -force;
+  elseif resolveInFrame == ResolveInFrameAB.world then
+    f_b_0     = -force;
+    frame_b.f =  Frames.resolve2(frame_b.R, f_b_0);
+  elseif resolveInFrame == ResolveInFrameAB.frame_resolve then
+    f_b_0     = -Frames.resolve1(frame_resolve.R, force);
+    frame_b.f =  Frames.resolve2(frame_b.R, f_b_0);
+  else
+    assert(false, "Wrong value for parameter resolveInFrame");
+    f_b_0     = zeros(3);
+    frame_b.f = zeros(3);
+  end if;
 
-   // Force and torque balance
-   r_0 = frame_b.r_0 - frame_a.r_0;
-   zeros(3) = frame_a.f + Frames.resolve2(frame_a.R, f_b_0);
-   zeros(3) = frame_a.t + Frames.resolve2(frame_a.R, cross(r_0, f_b_0));
   annotation (
     Icon(coordinateSystem(preserveAspectRatio=true,  extent={{-100,-100},{
             100,100}}), graphics={
diff --git a/Modelica/Mechanics/MultiBody/Forces/Internal/BasicTorque.mo b/Modelica/Mechanics/MultiBody/Forces/Internal/BasicTorque.mo
index 57c821a617..17a52732fb 100644
--- a/Modelica/Mechanics/MultiBody/Forces/Internal/BasicTorque.mo
+++ b/Modelica/Mechanics/MultiBody/Forces/Internal/BasicTorque.mo
@@ -1,15 +1,15 @@
 within Modelica.Mechanics.MultiBody.Forces.Internal;
 model BasicTorque
   "Torque acting between two frames, defined by 3 input signals"
+  extends Interfaces.PartialForce;
   import Modelica.Mechanics.MultiBody.Types.ResolveInFrameAB;
-  extends Modelica.Mechanics.MultiBody.Interfaces.PartialTwoFrames;
+
   Interfaces.Frame_resolve frame_resolve
     "The input signals are optionally resolved in this frame"
     annotation (Placement(transformation(
         origin={40,100},
         extent={{-16,-16},{16,16}},
         rotation=90)));
-
   Modelica.Blocks.Interfaces.RealInput torque[3](each final quantity="Torque", each final unit="N.m")
     "x-, y-, z-coordinates of torque resolved in frame defined by resolveInFrame"
     annotation (Placement(transformation(
@@ -23,7 +23,7 @@ model BasicTorque
 
   SI.Position r_0[3]
     "Position vector from origin of frame_a to origin of frame_b resolved in world frame";
-  SI.Torque t_b_0[3] "frame_b.t resolved in world frame";
+  SI.Torque t_b_0[3] "Torque frame_b.t resolved in world frame";
 
 equation
   assert(cardinality(frame_resolve) > 0, "Connector frame_resolve must be connected at least once and frame_resolve.r_0/.R must be set");
@@ -31,29 +31,26 @@ equation
   frame_resolve.t = zeros(3);
 
   r_0 = frame_b.r_0 - frame_a.r_0;
-  frame_a.f = zeros(3);
   frame_b.f = zeros(3);
 
-   if resolveInFrame == ResolveInFrameAB.frame_a then
-      t_b_0     = -Frames.resolve1(frame_a.R, torque);
-      frame_b.t =  Frames.resolve2(frame_b.R, t_b_0);
-   elseif resolveInFrame == ResolveInFrameAB.frame_b then
-      t_b_0     = -Frames.resolve1(frame_b.R, torque);
-      frame_b.t = -torque;
-   elseif resolveInFrame == ResolveInFrameAB.world then
-      t_b_0     = -torque;
-      frame_b.t =  Frames.resolve2(frame_b.R, t_b_0);
-   elseif resolveInFrame == ResolveInFrameAB.frame_resolve then
-      t_b_0     = -Frames.resolve1(frame_resolve.R, torque);
-      frame_b.t =  Frames.resolve2(frame_b.R, t_b_0);
-   else
-      assert(false, "Wrong value for parameter resolveInFrame");
-      t_b_0     = zeros(3);
-      frame_b.t = zeros(3);
-   end if;
+  if resolveInFrame == ResolveInFrameAB.frame_a then
+    t_b_0     = -Frames.resolve1(frame_a.R, torque);
+    frame_b.t =  Frames.resolve2(frame_b.R, t_b_0);
+  elseif resolveInFrame == ResolveInFrameAB.frame_b then
+    t_b_0     = -Frames.resolve1(frame_b.R, torque);
+    frame_b.t = -torque;
+  elseif resolveInFrame == ResolveInFrameAB.world then
+    t_b_0     = -torque;
+    frame_b.t =  Frames.resolve2(frame_b.R, t_b_0);
+  elseif resolveInFrame == ResolveInFrameAB.frame_resolve then
+    t_b_0     = -Frames.resolve1(frame_resolve.R, torque);
+    frame_b.t =  Frames.resolve2(frame_b.R, t_b_0);
+  else
+    assert(false, "Wrong value for parameter resolveInFrame");
+    t_b_0     = zeros(3);
+    frame_b.t = zeros(3);
+  end if;
 
-   // torque balance
-   zeros(3) = frame_a.t + Frames.resolve2(frame_a.R, t_b_0);
   annotation (
     Icon(coordinateSystem(preserveAspectRatio=true, extent={{-100,-100},{
             100,100}}), graphics={
diff --git a/Modelica/Mechanics/MultiBody/Interfaces/PartialForce.mo b/Modelica/Mechanics/MultiBody/Interfaces/PartialForce.mo
index f5729ce3ff..844fce359e 100644
--- a/Modelica/Mechanics/MultiBody/Interfaces/PartialForce.mo
+++ b/Modelica/Mechanics/MultiBody/Interfaces/PartialForce.mo
@@ -1,32 +1,37 @@
 within Modelica.Mechanics.MultiBody.Interfaces;
 partial model PartialForce
-  "Base model for force elements (provide frame_b.f and frame_b.t in subclasses)"
+  "Base model for force elements, used for textual modeling, i.e., for elementary models"
   extends PartialTwoFrames;
+
   SI.Position r_rel_b[3]
     "Position vector from origin of frame_a to origin of frame_b, resolved in frame_b";
+  Frames.Orientation R_rel
+    "Relative orientation object from frame_a to frame_b";
 equation
-  // Determine relative position vector between frame_a and frame_b
+  // Determine relative position and orientation
   r_rel_b = Frames.resolve2(frame_b.R, frame_b.r_0 - frame_a.r_0);
+  R_rel = Frames.relativeRotation(frame_a.R, frame_b.R);
 
   // Force and torque balance between frame_a and frame_b
-  zeros(3) = frame_a.f + Frames.resolveRelative(frame_b.f, frame_b.R, frame_a.R);
-  zeros(3) = frame_a.t + Frames.resolveRelative(frame_b.t + cross(r_rel_b, frame_b.f), frame_b.R, frame_a.R);
+  zeros(3) = frame_a.f + Frames.resolve1(R_rel, frame_b.f);
+  zeros(3) = frame_a.t + Frames.resolve1(R_rel, frame_b.t + cross(r_rel_b, frame_b.f));
+
   annotation (Documentation(info="<html>
 <p>
-All <strong>3-dimensional force</strong> and <strong>torque elements</strong>
-should be based on this superclass.
+All elementary <strong>3-dimensional force</strong> and
+<strong>torque elements</strong> should be based on this superclass.
 This model defines frame_a and frame_b, computes the relative
 translation and rotation between the two frames and calculates
 the cut-force and cut-torque at frame_a by a force and torque
 balance from the cut-force and cut-torque at frame_b.
 As a result, in a subclass, only the relationship between
-the cut-force and cut-torque at frame_b has to be defined as
-a function of the following relative quantities:
+the cut-force and cut-torque at frame_b (i.e., frame_b.f and frame_b.t)
+has to be defined as a function of the following relative quantities:
 </p>
 <blockquote><pre>
 r_rel_b[3]: Position vector from origin of frame_a to origin
             of frame_b, resolved in frame_b
-R_rel     : Relative orientation object to rotate from frame_a to frame_b
+R_rel     : Relative orientation object from frame_a to frame_b
 </pre></blockquote>
 <p>
 Assume that force f = {100,0,0} should be applied on the body
@@ -42,7 +47,7 @@ the definition should be:
 <strong>end</strong> Constant_x_Force;
 </pre></blockquote>
 <p>
-Note, that frame_b.f and frame_b.t are flow variables and therefore
+Note, that frame_b.f and frame_b.t are flow variables and, therefore,
 the negative value of frame_b.f and frame_b.t is acting at the part
 to which this force element is connected.
 </p>