+ * In the third mode, the faces can be reoriented equally to reference faces:
+
+ * If necessary, select 2D **Reference objects** (groups or/and sub-meshes) containing the reference faces, in the Object Browser or in the 3D Viewer. This field can be left empty, then orientation of an arbitrary face will be used as a reference.
+
+
+ .. image:: ../images/reorient_2d_refgroup.png
+ :align: center
+
+ .. centered::
+ The orientation of faces is given by reference face groups and/or sub-meshes.
+
+ * In the fourth mode, the faces can be reoriented according to volumes: