-<li>if you wish to convert standard mesh to quadratic or quadratic to standard;</li>
-<li>if you wish to place medium nodes of the quadratic mesh on the geometry (meshed object).</li>
+<li>If it is necessary to convert a linear mesh to quadratic or a quadratic
+ mesh to linear. **Convert to bi-quadratic** option does the same as
+ **Convert to quadratic** except for that TRIA7, QUAD9 and HEXA27
+ elements are created instead of TRIA6, QUAD8, and HEXA20 elements
+ respectively. Note that the choice is available only if the selected
+ mesh (or sub-mesh) contains both quadratic and linear elements, else the
+ direction of conversion is selected automatically.</li>
+<li>If it is necessary to place **medium nodes** of the quadratic mesh **on the
+ geometry** (meshed object). This option is relevant for conversion to
+ quadratic provided that the mesh is based on a geometry (not imported
+ from file).</li>