+ add attribute MatrixOfInertia to solid

git-svn-id: https://free-cad.svn.sourceforge.net/svnroot/free-cad/trunk@5337 e8eeb9e2-ec13-0410-a4a9-efa5cf37419d

src/Mod/Part/App/TopoShapeSolidPy.xml

@@ -23,6 +23,27 @@ absolute Cartesian coordinate system.</UserDocu>
       </Documentation>
       <Parameter Name="CenterOfMass" Type="Object"/>
     </Attribute>
+    <Attribute Name="MatrixOfInertia" ReadOnly="true">
+      <Documentation>
+        <UserDocu>Returns the matrix of inertia. It is a symmetrical matrix. 
+The coefficients of the matrix are the quadratic moments of 
+inertia. 
+
+ | Ixx Ixy Ixz 0 | 
+ | Ixy Iyy Iyz 0 | 
+ | Ixz Iyz Izz 0 | 
+ | 0   0   0   1 | 
+
+The moments of inertia are denoted by Ixx, Iyy, Izz. 
+The products of inertia are denoted by Ixy, Ixz, Iyz. 
+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.</UserDocu>
+      </Documentation>
+      <Parameter Name="MatrixOfInertia" Type="Object"/>
+    </Attribute>
     <Attribute Name="OuterShell" ReadOnly="true">
       <Documentation>
         <UserDocu>

src/Mod/Part/App/TopoShapeSolidPyImp.cpp

@@ -91,6 +91,20 @@ int TopoShapeSolidPy::PyInit(PyObject* args, PyObject* /*kwd*/)
     return 0;
 }
 
+Py::Object TopoShapeSolidPy::getMatrixOfInertia(void) const
+{
+    GProp_GProps props;
+    BRepGProp::VolumeProperties(getTopoShapePtr()->_Shape, props);
+    gp_Mat m = props.MatrixOfInertia();
+    Base::Matrix4D mat;
+    for (int i=0; i<3; i++) {
+        for (int j=0; j<3; j++) {
+            mat[i][j] = m(i+1,j+1);
+        }
+    }
+    return Py::Matrix(mat);
+}
+
 Py::Object TopoShapeSolidPy::getCenterOfMass(void) const
 {
     GProp_GProps props;