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What does it mean that a complete rig is generated using some kind of ORG bones? Does this topic come up only when we use Rigify? Or ORG bones are used without the participation of Rigify?

Why are the ORG bones stored in the generated rig, and a layer is allocated for them? How can they be used in the future?

White Raven
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2 Answers2

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Rigify is a custom Blender complex rig, with lots of bones and constraints. All bones have to be placed in an exact location, matching the model's features.

Using a simple source armature (wich is called Metarig) you can choose the placement of the deforming bones, then pressing the "Generate" button a Python script will create all the useful bones in the right placement, speeding up a lot the whole process.

In the bone layers of the generated rig you will find: layer 29 deforming bones (DEF), layer 30 machinary bones (MCH, which are meant not to be touched by the user), in layer 31-last a complete rig matching the original metarig (ORG).

All others bone layers contain all the control bones with a custom shape meant to be more easily controlled by animators.

There are some others Rigging addons, like Auto Rig Pro or BlenRig, where the same approach is used: you manually set some points and the addon does the rest of the job.

I often use the ORG bones to apply supplementary constraints (like if I want a weapon to be hold by the hand of the character).

josh sanfelici
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  • an interesting use of the ORG prefix. Does it make it easier to deal with the rigs than using the common technique of putting all such constrains on MCH bones? I might have to adopt it if it does. – Marty Fouts Dec 22 '21 at 16:26
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    Hi Marty, it just helps having all added constraints targets into a single bone layer, just for organization. – josh sanfelici Jan 05 '22 at 09:20
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As This answer explains,

Every rigger uses [their] own bone naming conventions, prefixes or suffixes, usually in agreement with animators for which the rig is intended (in studio). There is no standard, but there are however some commonly used terms [emphasis mine]

The answer goes on to explain that ORG is commonly used as a prefix for

original bones of metarigs from which the final rig is generated

As far as I know, Rigify does not use the ORG prefix in its metarigs. It certainly does not in the human or cat metarigs, the two I just checked. It does however use the prefix in the generated rig.

Rigify uses the ORG bones in the resulting rig as a way of caching the metarig, to aid it in the rare cases when you wish to regenerate a rig. You do not need to concern yourself with those bones otherwise, which is why they don't show up in the Rigify UI in pose mode. Although there is no proscription against it in the manual, I would not use the prefix for any bones I added to a generated rig.

And to answer your final question, yes, Rigify sorts the ORG bones into a layer. It uses the last bone layer, number 31 for this purpose.

Marty Fouts
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