From BlenderWiki

Armature Templating

The idea of templating is to use an already existing armature as base, template, to create a new one. The difference with a simple copy is that you can directly define the new one different in some aspects than its reference rig.

In Blender 2.49, the only templating tool is the bone sketching one (Etch-a-ton, described in the previous page), with its Template conversion method – so you should have read its page before this one!

Using Bone Sketching

So, basically, the Template conversion method of Bone Sketching tool will “map” a “copy” of existing bones to each selected stroke. The new bones will inherit their properties (influence, number of segments, etc.) from the template ones, but they might (will) have different lengths, rolls and rotations.

Before conversion.	After conversion.
Templating using another armature (Armature.002, shown on top), with the edited armature empty. Note the root bone’s name of the template chain (Chain_a, which is the chain formed by the first created bones of Armature.002). In the conversion result, you can see that the other chain (Chain_b) of Armatures.002 has been simply duplicated during conversion, without any mapping to the stroke.

Before conversion.	After conversion.
Templating using the selected bones of the same armature. If you would have selected the two chains (Chain_a and Chain_b), you would have get the same result as in previous example above.

Before conversion.	After conversion.
Templating using several strokes at once, some of them being polygonal (made of straight segments). The same chain (Chain_b) is mapped to each selected stroke. Note how the two bones are mapped to the three-straight-segments stroke.

Let’s first see some important points:

• This conversion method can use as reference bones either the selected bones in the currently edited armature, or all bones from another armature. In general, it’s a better idea to create new “templated” bones inside the “reference” armature, so you can precisely select which bones to use as template – if you want the new bones in a different armature, you can then use the Separate (CtrlAltP) and optionally Join (CtrlJ in Object mode) commands…
• This tool only considers one chain of bones, so it’s better to select only one chain of bones inside the current armature (or use a single-chain armature object as template). Else, the chain of the template containing the first created bones will be mapped to the selected strokes, and the other chains will just be “copied” as is, without any modification.
• This tool maps the same chain of bones on all selected strokes, so you can’t use multiple strokes to map a multi-chains template – you will rather get a whole set of new bones for each selected stroke!
• If you have strokes only made of straight segments, they must have at least as much segments as there are bones in the template chain (else, the newly created chain is not mapped at all to the stroke, and remains an exact duplicate of its template). If there are more segments than necessary, the conversion algorithm will chose the best “joints” for the bones to fit to the reference chain, using the same influence settings as for free segments (A, L and D settings, see below).
• If you try to Convert without template bones (i.e. either an empty armature selected as template, or no bones selected in the current edited armature), you’ll get the error message “No Template and no deforming bones selected”, and nothing will occur.

With current edited armature as template.	With another armature as template.
The Bone Sketching panel with Template conversion method enabled.

Now, let’s see the settings of this conversion method.

No, View, Joint buttons

These three toggle buttons (mutually exclusive) control how the roll angle of newly created bones is affected:

• No: Do not alter the bones roll (i.e. the new bones’ rolls fit their reference ones).
• View: Roll each bone so that one of its X, Y or Z local axis is aligned (as much as possible) with the current view’s Z axis.
• Joint: New bones roll fit their original rotation (as No option), but with regards to the bend of the joint with its parent.

With No roll option.	With View roll option.	With Joint roll option.
Templating: bone roll example. The Bone.003-to-Bone.005 chain is the mapped-to-stroke version of Bone-to-Bone.002 selected one, and Bone.001 has a modified roll angle.

Template drop-down list

Here you select the armature to use as template. If you choose None, the selected bones from the currently edited armature will be used as reference, else all bones of the other armature will be used.

A, L, D numeric fields

These settings control how the template is mapped to the selected strokes.

Each one can have a value between 0.0 and 10.0, the default being 1.0.

• A controls the influence of the angle of the joints (i.e. angle between bones) – the higher this value, the more the conversion process will try to preserve these joints angle in the new chain.
• L controls the influence of the bones’ length – the higher this value, the more the conversion process will try to preserve these lengths in the new bones.
• D controls the influence of the stroke’s shape – the higher this value, the more the conversion process will try to follow the stroke with the new chain.

A: 1.0; L: 1.0; D: 1.0.	A: 1.0; L: 0.0; D: 0.0.	A: 0.0; L: 1.0; D: 0.0.	A: 0.0; L: 0.0; D: 1.0.
Examples of Template conversions for various influence weights values, with one stroke quite similar to the template chain’s shape, and one stroke very different.

S and N text fields, “auto” button

These control how the new bones are named. By default, they just take the same names as the originals from the template – except for the final number, increased as needed. However, if the template bones have “&s” somewhere in their name, this “placeholder” will be replaced in the “templated” bones’ names by the content of the S text field (“S” for “side”). Similarly, a “&n” placeholder will be replaced by the N field content (“N” for “number”). If you enable the small “auto” button, the N field content is auto-generated, producing a number starting from nothing, and increased each time you press the Convert button, and the “&s” placeholder is replaced by the side of the bone (relative to the local X axis: “r” for negative X values, “l” for positive ones).

Before conversion (note the &n and &s placeholders in template bones’ names). After conversion: the placeholders have been replaced by the content of the S and N text fields of the Bone Sketching panel.

Naming and placeholders, using a simple leg template.

Before conversion (note that, in the Bone Sketching panel, the S and N fields are empty, and the small “auto” button is enabled). After conversion: the &n have been replaced by a number (none=0 for the first stroke…), incremented for each stroke, and the &s have been replaced by the r or l side codes.

Auto naming and placeholders, using a simple leg template.

Static text line

The line just above the Peel Objects button gives you two informations:

• The “n joints” part gives you the number of joints (i.e. bones’ ends, with connected ends considered as one joint), either from the selected bones of the edited armature, or in the whole other template armature.
• The second part is only present when another armature has been selected as template – it gives you the root bone’s name of the chain that will be mapped to the strokes. Or, while you are drawing a stroke with straight segments, the name of the bone corresponding to the current segment (and “Done” when you have enough segments for all bones in the template chain).