Rigify: implement optional custom pivot controls.

- Add an optional custom pivot between torso and the rest of the spine.
- Add a custom pivot rig that can be used as a parent of the spine.
- Add an optional custom pivot under limb IK controls.

1 files changed, 10 insertions, 0 deletions

diff --git a/rigify/base_rig.py b/rigify/base_rig.py
index 6b01c43a..b7a5d08c 100644
--- a/rigify/base_rig.py
+++ b/rigify/base_rig.py
@@ -258,6 +258,16 @@ class RigUtility(BoneUtilityMixin, MechanismUtilityMixin):
         self.owner.register_new_bone(new_name, old_name)
 
 
+class RigComponent(GenerateCallbackHost, RigUtility):
+    """Base class for utility classes that generate part of a rig using callbacks."""
+    def __init__(self, owner):
+        super().__init__(owner)
+
+        self.owner.rigify_sub_objects = objects = self.owner.rigify_sub_objects or []
+
+        objects.append(self)
+
+
 #=============================================
 # Rig Stage Decorators
 #=============================================