[bos #29336] problem in inertia calculus

diff --git a/doc/salome/gui/GEOM/input/inertia.doc b/doc/salome/gui/GEOM/input/inertia.doc
index bfb439b884130fdc15609ae0605a05b11b49405c..d0a37107f77bd76fb29c89263e00272b1074d0d6 100644 (file)
--- a/doc/salome/gui/GEOM/input/inertia.doc
+++ b/doc/salome/gui/GEOM/input/inertia.doc
@@ -8,7 +8,20 @@ This operation returns the axial moments of inertia for the selected geometrical
 
 The table displays:
 - 3*3 matrix of its own moments of inertia (in rows <b> 1:1, 2:1</b> and <b>3:1</b>) and  
 
 The table displays:
 - 3*3 matrix of its own moments of inertia (in rows <b> 1:1, 2:1</b> and <b>3:1</b>) and  

-- the relative moments of inertia (in row <b>IX & IY & IZ</b>)
+- the main (principal) moments of inertia (in row <b>IX & IY & IZ</b>)
+
+\note The matrix of inertia is returned in the central coordinate
+ system (G, Gx, Gy, Gz) where G is the centre of mass of the system
+ and Gx, Gy, Gz the directions parallel to the X(1,0,0), Y(0,1,0), Z(0,0,1)
+ directions of the absolute cartesian coordinate system.
+
+\note There is always a set of axes for which the products of inertia
+ of a geometric system are equal to 0. These axes are the principal
+ axes of inertia. Their origin is coincident with the center of mass
+ of the system. The associated moments are called the principal moments
+ of inertia. The principal axes are not reported by this functionality.
+
+\br

 
 \note This dialog supports navigation through the selectable objects (in OCC 3D viewer only):
 - Scroll mouse wheel with pressed \em Ctrl key or press \em "S", \em "P" keys when input focus is
 
 \note This dialog supports navigation through the selectable objects (in OCC 3D viewer only):
 - Scroll mouse wheel with pressed \em Ctrl key or press \em "S", \em "P" keys when input focus is


@@ -19,8 +32,8 @@ For more details, please refer to the \em "Functionality common for OCC and VTK
 of the GUI module's documentation.
 
 <b>TUI Command:</b> <em>geompy.Inertia(Shape),</em> where \em Shape is
 of the GUI module's documentation.
 
 <b>TUI Command:</b> <em>geompy.Inertia(Shape),</em> where \em Shape is

-a shape for which the own matrix of inertia and the relative moments of inertia are
-returned.
+a shape for which the own matrix of inertia and the main (principal) moments
+of inertia are returned.

 
 See also a \ref tui_inertia_page "TUI example".
 
 
 See also a \ref tui_inertia_page "TUI example".