From BlenderWiki

Armature visualization

General options

But let’s first see some general visualization properties of armatures, found in the Armature panel of the Editing context (F9). There are some extra visualization options specific to the Pose mode, described in the posing sub-part.

X-Ray

When enabled, the bones of the armature will always be drawn on top of the solid objects (meshes, surfaces, …) – i.e. they will always be visible and selectable (this is the same option as the one found in the Draw panel of the Object context and sub-context – F7). Very useful when not in Wireframe mode!

Octahedron/Stick/B-Bone/Envelope

These four buttons are mutually exclusive, and determines how are shown the bones of the armature, as well as some editing tool behavior.

A basic armature in Octahedron visualization, Edit mode.
Note the 40° rolled Bone.001 bone.

Octahedron

This is the default visualization, well suited for most of editing tasks. It materializes:

• The bone root (“big” end) and tip (“small” end).
• The bone “size” (its thickness is proportional to its length).
• The bone roll (as it has a square section).

The same armature in Stick visualization, Pose mode.
Note that Bone.001 roll angle is not visible (except by its XZ axes).

Stick

This is the simplest and most non-intrusive visualization. It just materializes bones by sticks of constant (and small) thickness – so it gives you no information about root and tip, nor bone size or roll angle.

The same armature in B-Bone visualization, Edit mode.

B-Bone

This visualization shows the curves of “smooth” multi-segmented bones, see the bone page for details.

The same armature in Envelope visualization, Pose mode.

Envelope

This visualization materializes the bone deformation influence. More on this in the bone page.

Axes

When enabled, the (local) axes of each bone are drawn (only relevant for Edit and Pose modes).

Names

When enabled, the name of each bone is drawn.

Shapes

When enabled, the default standard bone shape is replaced, in Object and Pose modes, by the shape of a chosen object (see below for details).

Colors

This is only relevant for Pose mode, and is described in details here.

Shaped Bones

Shaped Bones Example
The armature with shapes assigned to two bones, in Object mode. Note the centers of the Cone and Cube objects.
The same armature in Pose mode…
The (Pose mode) settings of the two shaped bones. Note that Bone.002’s shape is in wireframe (the W button), as shown above.

Blender allows you to give to each bone of an armature a specific shape (in Object and Pose modes), using another object as “template”. First of all, you have to enable the Shapes button (Armature panel). Then, to assign a custom shape to a bone, you have to:

• Switch to Pose mode (Ctrl⇆ Tab).
• Select the relevant bone (RMB click on it).
• Type the name of the object to use as bone shape in its OB text field (Armature Bones panel, Editing context, F9). The small W button just to the right, when enabled, will force the shape to always be drawn as wireframe (you can also enable this option from 3D views with Ctrl⇧ ShiftW » Draw Wire, disable it with AltW » Draw Wire, and toggle it with ⇧ ShiftW » Draw Wire…).

Note that:

• These shapes will never be rendered – as any bone, they are only visible in 3D views.
• Even if any type of object seems to be accepted by the OB field (meshes, curves, even metas…), only meshes really work – all other types just make the bone invisible, nothing is drawn…
• The center of the shape object will be at the root of the bone (see the bone page for root/tip).
• The object properties of the shape are ignored (i.e. if you make a parallelepiped out of a cube by modifying its dimensions in Object mode, you’ll still have a cube shaped bone…).
• The “along bone” axis is the Y one, and the shape object is always scaled so that one Blender Unit stretches along the whole bone length.

So to summarize all this, you should use as shape objects meshes, with their center at their lower-Y end, and an overall Y length of 1.0 BU.

Bone Layers

Each armature has sixteen “bone layers”, that allow you to organize it by “regrouping” its bones in layers – working similar to scene layers (those containing your objects). You can then “move” a bone to a given layer, hide or show one or several layers, etc.

Showing/hiding bone layers

Only bones in active layers will be visible/editable – but they will always be effective (i.e move objects or deform geometry), being in an active layer or not. To (de)activate a layer, you have several options, depending in which mode you are in:

• In all modes, use the row of small buttons at the top of the Display Options group, Armature panel. If you want to enable/disable several layers at once, as usual, hold ⇧ Shift while clicking…

• In Edit and Pose modes, you can also do this from the 3D Views, either by using the menu (Armature » Switch Armature Layers or Pose » Switch Armature Layers), or the ⇧ ShiftM shortcut, to display a small pop-up dialog containing the same buttons as described above (here again, you can use ⇧ ShiftLMB clicks to (de)select several layers at once).

Moving bones between layers

Obviously, you have to be in Edit or Pose modes to move bones between layers – note that as with objects, bones can lay in several layers at once, just use the usual ⇧ ShiftLMB clicks… First of all, you have to select the chosen bone(s)!

• In the Button window, use the “layer buttons” of each selected bone “sub-panel” (Armature Bones panel) to control in which layer(s) it lays.

• In the 3D View window, use the menu (Armature » Move Bone To Layer or Pose » Move Bone To Layer) or hit M to show the usual pop-up layers dialog. Note that this way, you assign the same layers to all selected bones.

Locking layers in proxies

You can lock a given bone layer for all proxies of your armature, i.e. all bones in this layer won’t be editable. To do so, in the Armature panel, CtrlLMB click on the relevant button – the locked layer will then display a small black dot at its center.

Hiding Bones

You do not have to use bone layers to show/hide some bones. As with objects, vertices or control points, you can use the H key:

• H will hide the selected bone(s).
• ⇧ ShiftH will hide all bones but the selected one(s).
• AltH will show all hidden bones.

You can also use the Hide button of each bone sub-panel (in the Armature Bones panel, Editing context).

Note that hidden bones are specific to a mode – i.e. you can hide some bones in Edit mode, they will still be visible in Pose mode, and vice-versa. Hidden bone in Pose mode are also invisible in Object mode. And in Edit mode, the bone to hide must be fully selected, not just his root or tip…