Hey there, tried looking through previous videos to find the explanation as well as searching through this one and couldn't find it. I get the root, the controllers and the bendy bone, but why are there mechanism bones?
Hi Andrew, check out Chapter 03 - this video explains what mechanism bones are.
https://cgcookie.com/lessons/01-rigging-concepts-in-a-nutshell
DEF- are deformation bones.
No prefix - Control Bones
MCH - Mechanism bones (they are needed to make the other bones do what you need them to do)
Thanks for the reply. @waylow - I've tested this while leaving the MCH bones out of the armature and it works without them. I get that they may be necessary for more complex things, I'm just not seeing what it is they actually do.
EDIT: I see that they preserve the transforms
https://blender.stackexchange.com/questions/41587/copy-rotation-bone-constraint-not-smooth/41591#41591
But do some constraints require them and others don't?
In the case of this rig it is so you can have world aligned controls.
Some solutions will need MCH bones to avoid problems. For example, you might need to avoid a dependency cycle where the target of the constraint would otherwise be a child of that bone. The child depends on the parent, but the parent depends on the child.....that's going to cause some issues.
MCH bones can come to the rescue here.