*******
Normals
*******

Introduction
============

Todo.

.. Explain what are normals


.. figure:: /images/modeling_meshes_editing_normals.png

   Normals visualization.


.. _modeling-meshes-editing-normals-editing:

Editing
=======

Flip Direction
--------------

.. admonition:: Reference
   :class: refbox

   | Mode:     Edit Mode
   | Panel:    :menuselection:`Tool Shelf --> Shading/UVs --> Shading --> Normals: Flip Direction`
   | Menu:     :menuselection:`Mesh --> Normals --> Flip` or :menuselection:`Specials --> Flip Normals`


Well, it will just reverse the normals direction of all selected faces.
Note that this allows you to precisely control the direction (**not** the orientation,
which is always perpendicular to the face) of your normals, as only selected ones are flipped.


Recalculate Normals
-------------------

.. admonition:: Reference
   :class: refbox

   | Mode:     Edit Mode
   | Panel:    :menuselection:`Tool Shelf --> Shading/UVs --> Shading --> Normals: Recalculate`
   | Menu:     :menuselection:`Mesh --> Normals --> Recalculate Outside` and
     :menuselection:`Mesh --> Normals --> Recalculate Inside`
   | Hotkey:   :kbd:`Ctrl-N` and :kbd:`Ctrl-Shift-N`


These tools will recalculate the normals of selected faces so that they point outside
(respectively inside) the volume that the face belongs to.
This volume do not need to be closed. In fact, this means that the face of interest must be
adjacent with at least one non-coplanar other face.
For example, with a *Grid* primitive, recalculating normals does not have a meaningful result.

.. tip::

   For Visualization in *Edit Mode* see :ref:`mesh-display-normals`.