manual/addons/rigging/rigify/basics.rst

@@ -64,14 +64,14 @@ Rigify Human Alignment Tips
   they are almost useless if you plan to make facial animation through shape keys.
   Consider removing face features from your character if they aren't really needed.
   If you don't need the face all the face bones can be deleted.
-  All the face bones are on the first armature layer by default.
-  You can select them by displaying only bone layer 1, selecting all of its content and
+  All the face bones are in the *Face* armature bone collection by default.
+  You can select them by displaying only that collection, selecting all of its content and
   then deleting the bones in Edit Mode to correctly remove the face.
 
   If you want to scale all the face bones at once, consider scaling the face master bone
   in Pose Mode (see Pose Mode matching method).
   The face master bone is placed in the same position of the head bone.
-  To select it easily, hide all other bone layers.
+  To select it easily, hide all other bone collections.
 
   For more tips, see the :doc:`Positioning Guide </addons/rigging/rigify/bone_positioning>`.
 
@@ -147,13 +147,13 @@ Binding the Geometry to the Rig
 
 To bind the geometry to the rig you can use your preferred tools. Just few things you have to know:
 
-- All the deforming bones are on the armature layer 30.
+- All the deforming bones are in the *DEF* bone collection.
 - Eyes and Teeth bones of the legacy face are not deforming. You are supposed to bind the eyes and
   teeth geometry through Child Of constraints.
 - Usually armature deform with automatic weights do a really good job out of the box
   if you correctly place your bones (and there is enough topology to work with!).
 
-For more detailed information on armature layers, Armature modifier and weight painting refer to the Blender manual.
+For more detailed information on bone collections, Armature modifier and weight painting refer to the Blender manual.
 
 
 .. _bpy.types.Armature.rigify:
@@ -172,27 +172,36 @@ By using options in the Advanced sub-panel, it is possible to:
 - Choose whether to use linked duplicates for left and right side widgets.
 - Execute a script data-block after generation.
 
-
 Advanced Options Sub-Panel
 --------------------------
 
+.. figure:: /images/addons_rigging_rigify_basics_advanced-panel.png
+   :align: right
+   :width: 300px
+
 Advanced rig generation options are by default hidden in a sub-panel. Click on the *Advanced* line to open it.
 
 Some of the options will be automatically set by Rigify if they have no value when a rig is generated,
 while others are fully controlled by the user.
 
-Target Rig :guilabel:`auto`
-   This option specifies the generated rig to overwrite when re-generating from this metarig.
+Rig Name
+   When a brand new rig is generated, as opposed to overwriting an existing one, the value of this option
+   is used to name it.
 
-   If the option is not set, Rigify will generate a new rig object and store it in this option.
-   The new object will be named based on the name of the metarig according to the following rules:
+   If this field is empty, the new object will be named based on the name of the metarig according
+   to the following rules:
 
    * If the name contains ``META``, it is replaced with ``RIG``.
    * If the name contains ``metarig``, it is replaced with ``rig``.
    * Otherwise, ``RIG-`` is prepended to the name.
 
-   When overwriting an existing rig object specified by the option, its name is not changed,
-   allowing it to be freely renamed if the default naming scheme doesn't fit.
+   When overwriting an existing rig object specified by the *Target Rig* option, its name is not changed,
+   allowing it to be freely renamed without having to keep the value of this option in sync.
+
+Target Rig :guilabel:`auto`
+   This option specifies the generated rig to overwrite when re-generating from this metarig.
+
+   If the option is not set, Rigify will generate a new rig object and store it in this option.
 
    .. note::
 
@@ -204,13 +213,13 @@ Rig UI Script :guilabel:`auto`
    works in the same manner as *Target Rig*.
 
    The script controls the UI in the 3D Viewport that allows conveniently switching visible
-   bone layers, changing custom properties, converting between IK and FK and so on.
+   bone collections, changing custom properties, converting between IK and FK and so on.
 
 Widgets Collection :guilabel:`auto`
    This reference specifies the collection containing generated widgets, and
    works in the same manner as *Target Rig*.
 
-Force Widget Update
+Overwrite Widget Meshes
    If enabled, Rigify will generate new widgets every time the rig is re-generated. By default,
    it tries to reuse the already generated widget objects that exist in the widget collection,
    allowing them to be manually edited to fit the character better.

manual/addons/rigging/rigify/metarigs.rst

@@ -5,7 +5,8 @@ Creating Meta-rigs
 
 #. Add a single bone from the :menuselection:`Add --> Armature` menu.
 #. Go in armature Edit Mode and build the meta rig by samples or Rigify-types.
-#. Define Rigify layers, bone grouping and selection sets.
+#. Define the :ref:`Rigify bone collection UI <bpy.types.BoneCollection.rigify_ui_row>`,
+   :ref:`color sets <bpy.types.Armature.rigify_colors>`, and selection sets.
 #. In the armature properties click on the *Generate* button to generate the rig.
 
 
@@ -59,7 +60,7 @@ Just add a single bone from the *Add* menu.
 
 .. tip::
 
-   At this stage naming the newly added armature "meta-rig" is a good idea.
+   At this stage naming the newly added armature ``metarig`` is a good idea.
    You can do it at any time (or not at all) but it's suggested to do it before going on
    so it will always be clear on which armature you have to work when editing the meta-rig structure.
 
@@ -77,7 +78,7 @@ Building a meta-rig from scratch in Edit Mode can be done in two ways:
 Adding Samples (Basic)
 ^^^^^^^^^^^^^^^^^^^^^^
 
-Adding samples in Edit Mode is a good way to start building a meta-rig.
+Adding pre-defined samples in Edit Mode is a good way to start building a meta-rig.
 This way you can become familiar with the available building blocks and how they are meant to be used.
 To add a rig sample:
 
@@ -90,11 +91,38 @@ To add a rig sample:
 For the list of available samples, see the :doc:`Rig Types </addons/rigging/rigify/rig_types/index>` page.
 
 
+.. _bpy.types.PoseBone.rigify_type:
+.. _bpy.types.RigifyParameters:
+
 Using Rig Types (Advanced)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-#. Create your bone chains in Edit Mode.
-#. Assign the correct rig type to the first bone of each chain in Pose Mode.
+.. figure:: /images/addons_rigging_rigify_metarigs_rigify-type-panel.png
+   :align: right
+   :width: 300px
+
+For full control, you can use the Rigify Type panel of bone properties in Pose Mode to assign
+any Rigify sub-rig type to any bone, as well as change its options.
+
+For the list of available sub-rig types and their options, see the :doc:`Rig Types </addons/rigging/rigify/rig_types/index>` page.
+
+At the top of the panel you can find a field specifying the rig type for the active bone. The drop-down list
+can be optionally filtered by the :doc:`Feature Set </addons/rigging/rigify/feature_sets>` it belongs to.
+
+Below that you can change options relevant to the selected rig type, if it has any.
+
+Bone Collection References
+""""""""""""""""""""""""""
+
+Some rig types that generate many control bones have options that reference
+:ref:`Bone Collections <bpy.types.BoneCollection.rigify_ui_row>`. These reference lists have a standard UI with
+the following features:
+
+* A checkbox controlling whether the reference should be used.
+* A button to copy the reference list contents from the active to all selected bones.
+* A plus button to add a new reference to the list.
+* A list of references, each entry with a field to specify the target collection,
+  and a button to remove the entry from the list.
 
 .. note::
 
@@ -113,7 +141,7 @@ Using Rig Types (Advanced)
 Custom Root Bone
 ^^^^^^^^^^^^^^^^
 
-If the meta-rig contains a bone called "root", it is used as the root control bone instead of creating a new one.
+If the meta-rig contains a bone called ``root``, it is used as the root control bone instead of creating a new one.
 This allows changing the rest position of the root bone, assigning a custom widget,
 or adding custom properties to the bone.
 
@@ -121,71 +149,130 @@ The custom root bone must have no parent, and use the :ref:`basic.raw_copy <rigi
 type or none.
 
 
-Layers, Bone Groups & Selection Sets
-====================================
+.. _bpy.types.Armature.rigify_colors:
 
-:ref:`Armature Layers <bpy.types.Armature.layers>` are usually used to isolate bones.
-Rigify can take advantage of armature layer to generate extra features and the user interface for the final rig.
-Rigify layers are displayed in a vertical layout inside their own separate panel named Rigify Layer Names.
+Color Sets
+==========
 
-- The first column shows the layer number.
-- The second column is a display toggle.
+.. figure:: /images/addons_rigging_rigify_metarigs_color-sets-panel.png
+   :align: right
+   :width: 300px
 
-  This toggle controls the armature layer visibility.
-  It has the same effect of enabling/disabling the layer visibility from the top armature layers menu.
-  It is just redrawn here for a simplicity.
+The Color Sets panel is used to define the bone color scheme for the final rig. The colors from the list
+can be associated with bone collections from the relevant panel.
 
-- The third column sets a specific layer name to be used to build the rig UI of the final rig.
-  If set, a button with the specified name will be created in the ``rig_ui_template`` to control the visibility of
-  this specific armature layer. If layer contains at least one bone but its name field is empty,
-  a button with no name will be created in the rig UI.
-
-- The fourth column defines in which UI row the layer button will be created.
-
-  This numbers define the layer ordering in the UI and will ignore the effective layer number.
-  If two layer have the same row number their UI buttons will be created in the same row.
-
-- The fifth column is a toggle for the selection set.
-
-  If checked a selection set with that name will be created and associated to the final rig.
-
-- The sixth column defines the Rigify Bone Grouping.
-
-  If Rigify Bone Groups are set, the user can make the association between
-  the bones on the layer and the specified bone group from the list.
-  The controls on the final rig will inherit the bone grouping through this value.
-
-- The seventh column displays -- if set -- the associated bone group name.
-
-In order to use the Bone Groups in the *Rigify Layer Names* fields,
-*Rigify Bone Groups* must be set through the specific panel.
-Usually this panel is displayed just above Rigify Layer Names panel.
-
-Rigify Bone Groups are used to define bone colors on the final rig.
-The top two rows of the Rigify Bone Groups panel are used to define the bone colors general behavior.
+The top two rows of the Color Sets panel are used to define the general behavior of the bone colors.
 Usually color themes use a gradient of colors to define the different bone states: default, selected and active.
 When multiple color themes are used in the same rig, identifying which bone is selected or
 active can be tricky since each color will have its corresponding state.
 
-To override this behavior Rigify Bone Groups unifies the active and selected states with the same color.
+To override this behavior Rigify unifies the active and selected states using the same color.
 This is defined by two values:
 
 Unified Selected/Active Colors
    When this option is active adding a bone group in the list will always keep the colors consistent.
-   When a color scheme is added as from a theme, the color scheme is loaded as is.
+   When a color scheme is added from a theme, the color scheme is loaded as is.
    Click on the *Apply* button to force the system to unify selected and active colors.
 
 Selected/Active Colors
-   This two color fields define respectively *Selected* and *Active* colors.
-   By default Rigify reads this colors from the theme defined by the user in the Blender preferences.
+   This two color fields define respectively the *Selected* and *Active* colors.
+   By default Rigify reads these colors from the theme defined by the user in the Blender preferences.
    This way the *Selected*/*Active* colors can always have a predictable and consistent behavior in the UI.
-   The colors can be customized by clicking on the relative color field.
+   The colors can be customized by clicking on the relevant color field.
    To reset them to the Blender current theme value just click on the button with the update icon.
 
-Bone Groups can be added and deleted as done in the general Bone Group panel
-by clicking on the ``+`` or ``-`` buttons.
-All Bone Groups can be deleted at once by clicking on the Specials menu.
+Color Sets can be added and deleted by clicking on the ``+`` or ``-`` buttons.
+All color sets can be deleted at once by clicking on the Specials menu.
 
-To add the predefined Rigify Default Bone Groups list click on *Add Standard* button.
+To add the colors from the predefined Rigify default color scheme (as shown in the image) to the list click
+the *Add Standard* button.
 
 To add a specific theme with its own color scheme, select it from the list and click on the *Add From Theme* button.
+
+
+.. _bpy.types.BoneCollection.rigify_ui_row:
+
+Bone Collections UI
+===================
+
+.. figure:: /images/addons_rigging_rigify_metarigs_bone-collections-panel.png
+   :align: right
+   :width: 300px
+
+:doc:`Bone Collections </animation/armatures/bones/bone_collections>` are used to group related bones together
+so that they can be hidden or revealed together.
+
+Rigify can take advantage of collections to generate extra features and the user interface for the final rig.
+A panel named :ref:`Rig Layers <rigify.rig_ui_template.RigLayers>` is generated with buttons for hiding the
+collections, arranged in an intuitive layout.
+
+The Bone Collections UI panel allows configuring the layout of that generated panel, as well as specifying some
+other settings for bone collections, such as the color set to use.
+
+The top of the panel is occupied by a list that duplicates the main bone collection list, but displays additional
+properties, such as the color set, whether the collection has a button, or whether it generates a selection set.
+
+Validate Collection References
+  Some sub-rig types have :ref:`references <bpy.types.RigifyParameters>` to bone collections in their properties.
+  Rigify uses a referencing scheme that is robust to collection renames, but deleting collections or joining armatures
+  can still lead to broken references.
+
+  This button runs a scan that validates and normalizes all collection references, reporting any errors, and
+  reducing the chance of breakage being caused by subsequent user actions.
+
+  This scan is also performed automatically every time the rig is generated.
+
+  .. warning::
+    To avoid breakage this operation should be used both immediately before and after joining two metarig armatures.
+    More specifically, it must be always done between the actions of renaming any collections and joining.
+
+Color Set
+  Specifies the :ref:`color set <bpy.types.Armature.rigify_colors>` to use for bones in this collection. If a bone
+  belongs to multiple collections, in general the collection located earlier in the list has priority.
+
+Add Selection Set
+  Specifies whether a selection set should be generated for this collection.
+
+UI Row
+  If nonzero, specifies which row of the :ref:`Rig Layers <rigify.rig_ui_template.RigLayers>` panel should contain the
+  button controlling the visibility of this collection. When zero, no button is generated, and the collection is hidden.
+
+UI Title
+  This field can be used to override the title used on the UI button to be distinct from the true collection name.
+  Unlike collection names, titles are not required to be unique, so this can be used to reduce clutter by relying
+  on contextual cues within the panel.
+
+UI Layout sub-panel
+-------------------
+
+.. figure:: /images/addons_rigging_rigify_metarigs_bone-collections-layout-panel.png
+   :align: right
+   :width: 300px
+
+The UI Layout sub-panel provides a WYSIWYG editor for the layout of the generated UI panel
+(as defined by the UI Row and UI Title settings above).
+
+Each row contains three buttons at the end:
+
+Arrow
+   Moves the active collection button to this row.
+Plus
+   Inserts a new row before the current one.
+Minus
+   Removes the current row and shifts all buttons up.
+
+To the left of the editing control buttons, rows display buttons corresponding to the collections, same as the final
+UI, except that rather than hiding or unhiding, clicking these buttons selects the collection.
+
+For the active collection the selection button is replaced with an input field for editing the UI Title, and an **X**
+button to unassign the collection from the UI.
+
+For any collections not assigned to the UI, their select buttons are displayed in a separate section at the bottom
+of the sub-panel.
+
+The ``Root`` collection will be added and/or assigned a UI button automatically if necessary when the rig is generated.
+If desired, it is possible to manually assign UI buttons to the internal ``ORG``, ``DEF`` and ``MCH`` collections.
+
+.. tip::
+   Blank rows appear much thinner in the final interface, since they don't have to contain editing buttons, and can be
+   used as logical separators.

manual/addons/rigging/rigify/rig_features.rst

@@ -6,23 +6,165 @@ Generated Rig Features
 After human rig generation a new armature named ``rig`` will be added to your scene.
 This is the character rig you have generated from the human meta-rig and will contain all the features.
 
+
+Common Features
+===============
+
+.. _rigify.rig_ui_template.RigBakeSettings:
+.. _rigify.rig_ui_template.RigUI:
+.. _rigify.rig_ui_template.RigLayers:
+
+Rig UI Panels
+-------------
+
+.. figure:: /images/addons_rigging_rigify_rig-features_rig-ui-panels.png
+   :align: right
+   :width: 200px
+
+The generated rig is accompanied by a script that implements a set of panels that appear in the Item
+tab of the 3D view sidebar when a bone belonging to the generated rig is active.
+
+Rig Bake Settings
+^^^^^^^^^^^^^^^^^
+
+This panel is displayed if the armature has an active :doc:`Action </animation/actions>`, and
+is used by operators that apply an operation to multiple keyframes.
+
+Bake All Keyed Frames
+   When enabled, the operator computes and keyframes its result on every frame that has a key for any of the
+   bones, as opposed to just relevant ones.
+Limit Frame Range
+   When enabled, the operator is limited to a certain frame range.
+
+   Start, End
+      Specify the frame range to process.
+   Get Frame Range
+      Sets the baking frame range from the scene frame range.
+
+Rig Main Properties
+^^^^^^^^^^^^^^^^^^^
+
+This panel shows properties and operators that are relevant to the selected bones.
+
+Rig Layers
+^^^^^^^^^^
+
+This panel contains buttons for toggling visibility of bone collections.
+
+The layout and labels of the buttons are defined in the metarig
+:ref:`Bone Collection UI <bpy.types.BoneCollection.rigify_ui_row>` panel.
+
+
+Common Controls
+---------------
+
+Rigify rigs are built from standardized components called sub-rigs, which are linked together in a parent-child
+hierarchy. Although the precise behavior of each sub-rig is determined by its implementation, there are certain
+conventions that are followed by many of them.
+
+Root Bone
+^^^^^^^^^
+
+Every Rigify rig has a bone called `root`, which serves as a parent for all bones of the rig.
+It is assigned to a bone collection called `Root`. Unless the metarig has a custom bone
+of that name, it is positioned at the origin of the rig object. Its widget looks like
+a circle with four arrow shaped protrusions.
+
+.. figure:: /images/addons_rigging_rigify_rig-features_arm-controls.png
+   :align: right
+   :width: 200px
+
+Limb Master
+^^^^^^^^^^^
+
+Many limb-like sub-rigs have a gear-shaped bone at their base.
+
+This bone can in some cases be used to transform the whole sub-rig as a rigid unit, and is also used as a container
+for its custom properties that are displayed in the *Rig Main Properties* panel. If you are looking in the Graph editor
+for the animated values of the properties, this is most likely the bone to look at.
+
+As an exception, if multiple controls of the sub-rig need their own copy of conceptually the same property,
+it may be placed on those controls directly instead.
+
+Tweak Controls
+^^^^^^^^^^^^^^
+
+These controls look like blue spheres in the default color scheme, and are the final control layer above the
+deformation bones themselves.
+
+Tweaks are subordinate to the general IK or FK limb position but can be moved apart, twisted and scaled freely,
+even reaching virtually impossible limb shapes.
+
+Rubber Tweak
+   .. figure:: /images/addons_rigging_rigify_rig-features_rubber-tweak.png
+      :align: right
+      :width: 200px
+
+   Some sub-rigs provide a slider in their *Rig Main Properties* when tweaks are selected, which controls
+   the smoothness of the Bendy Bone joint at that position. When zero, the joint deforms with a sharp bend,
+   while setting it to 1 makes the transition smooth for a more rubber hose cartoon like appearance.
+
+Custom Pivots
+^^^^^^^^^^^^^
+
+Some bones that can be freely moved in space (like IK controls) can be optionally accompanied by a custom pivot
+control. These controls usually look like a plain axes empty with the axis lines capped with squares or crosses,
+like the one in the image above. The control can be freely moved to change the location of the pivot, and then
+rotated or scaled to transform the target bone around the pivot.
+
+IK and FK Switching
+^^^^^^^^^^^^^^^^^^^
+
+.. figure:: /images/addons_rigging_rigify_rig-features_ik-fk-switch.png
+   :align: right
+   :width: 200px
+
+A number of rig types provides both IK and FK controls (red for IK and green for FK in the image above),
+with an ability to switch and snap between them.
+
+Switching is controlled by a slider in *Rig Main Properties*, usually blending between full IK at 0 and full FK at 1.
+
+Snapping one type of controls to the shape of the other is done via buttons, which form a group of three
+in their complete set:
+
+* The main button will snap on the current frame, and auto-key the result if enabled.
+* The *Action* button will bake the change on multiple keyframes, according to *Rig Bake Settings*.
+* The *Clear* button will delete keyframes on the corresponding controls within the bake interval.
+
+Parent Switching
+^^^^^^^^^^^^^^^^
+
+.. figure:: /images/addons_rigging_rigify_rig-features_parent-switch.png
+   :align: right
+   :width: 200px
+
+Some freely movable controls, e.g. usually the IK controls, can have a mechanism to switch their parent bone
+between a set of choices, including the root bone, or none at all.
+
+This mechanism is exposed in the *Rig Main Properties* panel through a row with three controls:
+
+* A button that presents a dropdown menu, which allows switching the parent on the current frame while
+  preserving the bone position and orientation in the world space.
+* An input field that exposes the raw switch property for keyframing and direct manipulation. Values correspond to
+  positions in the dropdown list.
+* A button to apply the position preserving parent switch over the bake range of keyframes.
+
+.. note::
+   When manually placing a Child Of constraint on the control bone, the built-in parent should be switched to none.
+
 Limbs
 =====
 
-Each limb will have a gear widget at its base. This is the utility bone that
-contains all the sub-rig properties. The rig features will be displayed anyway
-when the affected bone is selected but if you are looking in the Graph editor for
-those properties' animated values, this is most likely the bone to look at.
+Limbs have a master bone and tweaks. Depending on the user defined meta-rig options,
+multiple deform bone segments with tweaks will be created.
 
-Depending on the user defined meta-rig options, multiple deform bone segments will be created.
-Each bone can be controlled by tweak controls placed at the respective bone's head/tail.
-Tweaks are subordinate to the general IK or FK limb position but can be moved apart,
-twisted and scaled freely, even reaching virtually impossible limb shapes.
+The IK control may have an optional custom pivot, as well as additional predefined pivots.
 
 Rigify's limbs have the following controls in the Sidebar panel:
 
 .. figure:: /images/addons_rigging_rigify_rig-features_limb-properties.png
    :align: right
+   :width: 200px
 
 FK Limb Follow :guilabel:`Slider`
    When set to 1 the FK limb will not rotate with the torso and will retain is rotation
@@ -32,11 +174,7 @@ IK-FK :guilabel:`Slider`
    Controls whether the limb follows IK or FK controls, blending between full IK at 0 and full FK at 1.
 
 IK<->FK Snapping :guilabel:`Buttons`
-   To snap one type of controls to another use the appropriate buttons.
-
-   Each snap direction has buttons to update just the current pose, bake the whole animation in the
-   current *Action*, or *Clear* keyframes instead of snapping. The buttons dealing with keyframes
-   use options from an additional panel to control the range of frames to bake.
+   Snaps one type of controls to another.
 
 IK Stretch :guilabel:`Slider`
    Blends between the limb stretching freely at 1, or having its maximum length constrained at 0.
@@ -47,19 +185,205 @@ Toggle Pole :guilabel:`Switch`
    When set to 1 the classic pole vector will be displayed and used to orient the IK limb.
    The arrow will continue to handle the scale and the location of the IK limb base.
 
-   Similar to IK-FK Snapping, the row includes buttons to convert the current pose between types,
+   Similar to *Parent Switching*, the row includes buttons to convert the current pose between types,
    or bake the whole action.
 
 IK Parent :guilabel:`Switch`
-   Switches the effective parent of the main IK control, with different integer values corresponding
-   to choices from a list.
-
-   The row includes buttons that allow converting the current pose via choosing from a menu,
-   or baking the whole action.
+   Switches the effective parent of the main IK control.
 
 Pole Parent :guilabel:`Switch`
    Switches the effective parent of the classic IK Pole control.
 
+Arms
+----
+
+.. figure:: /images/addons_rigging_rigify_rig-features_hand-controls.png
+   :align: right
+   :width: 200px
+
+:ref:`Arms <rigify.rigs.limbs.arm>` have the simplest control structure: the IK controls consist of the main IK
+control, the optional custom pivot control, and the optional wrist control (the bent circle), which pivots around
+the tail rather than the head of the hand bone.
+
+There are no additional controls in the *Rig Main Properties* panel.
+
+Legs
+----
+
+:ref:`Legs <rigify.rigs.limbs.leg>` have a more complicated setup, which has:
+
+.. figure:: /images/addons_rigging_rigify_rig-features_foot-controls.png
+   :align: right
+   :width: 200px
+
+IK & FK Toe :guilabel:`Optional`
+   Two separate IK and FK controls for the toe (this is  on by default and recommended for stable IK<->FK snapping).
+IK Heel
+   A heel control which can be rotated to command forward or backward roll, sideways rock, or yaw of the heel.
+Toe Pivot :guilabel:`Optional`
+   An extra pivot control rotating around the base of the toe.
+Custom Pivot :guilabel:`Optional`
+   A custom pivot control.
+
+The properties panel has two additional features:
+
+.. figure:: /images/addons_rigging_rigify_rig-features_foot-properties.png
+   :align: right
+   :width: 200px
+
+IK->FK Snap With Roll :guilabel:`Buttons`
+   Standard IK to FK snapping resets the transformations of all IK controls other than the main one. This is
+   not convenient to use in an animation that involves the use of the heel control, because roll and rock would
+   be folded into the transformation of the main control.
+
+   This alternative snapping operator tries to deduce the rotation of the heel control so as to keep the main
+   IK control parallel to the ground plane inferred from the *current* orientation of the IK control. The operator
+   has options to specify which rotational axes to use for the heel control rotation.
+
+Roll On Toe :guilabel:`Slider` :guilabel:`Optional`
+   If enabled in the sub-rig settings, this slider can be used to control whether the heel rotation (excluding
+   backward roll) is applied at the base or the tip of the toe.
+
+Fingers & Tentacles
+===================
+
+Simple Tentacle
+---------------
+
+.. figure:: /images/addons_rigging_rigify_rig-features_simple-controls.png
+
+The simplest type of rig for a finger or appendage in general is the
+:ref:`simple tentacle <rigify.rigs.limbs.simple_tentacle>` sub-rig. It has only basic FK controls and tweaks,
+with the only automation being the ability to copy the local rotation of a FK joint to the next one.
+
+Advanced Finger
+---------------
+
+.. figure:: /images/addons_rigging_rigify_rig-features_finger-controls.png
+
+For the case of fingers, there is a dedicated :ref:`finger <rigify.rigs.limbs.super_finger>` sub-rig type,
+which provides:
+
+Master
+   A master control, which can be used to rotate the finger as a whole, as well as to bend it via Y scaling.
+FK Chain
+   FK control chain (green) that can operate as semi-tweaks through allowing translation.
+IK Control :guilabel:`Optional`
+   IK control for the tip.
+
+   .. note::
+      IK in this sub-rig is rudimentary and operates as an adjustment for FK. The intended way of use is to pose
+      the finger in FK, and then use FK->IK snap and enable IK if it is necessary to pin the tip of the finger
+      in place.
+
+The properties panel has the following features:
+
+.. figure:: /images/addons_rigging_rigify_rig-features_finger-properties.png
+   :align: right
+   :width: 200px
+
+Finger IK :guilabel:`Slider` :guilabel:`Optional`
+   Slider controlling the influence of the IK.
+
+FK<->IK Snapping :guilabel:`Buttons` :guilabel:`Optional`
+   Snaps the IK control to the end of the finger, or adjusts the FK controls to the result of the IK correction.
+
+Curvature :guilabel:`Slider`
+   Has the same effect as *Rubber Tweak* on limbs, controlling the rubber hose cartoon effect.
+
+Spline Tentacle
+---------------
+
+.. figure:: /images/addons_rigging_rigify_rig-features_spline-controls.png
+
+   Spline Tentacle (Stretch To Fit, Manual Squash & Stretch)
+
+.. figure:: /images/addons_rigging_rigify_rig-features_spline-controls-tip.png
+
+   Spline Tentacle (Direct Tip Control)
+
+The :ref:`spline tentacle <rigify.rigs.limbs.spline_tentacle>` is an advanced rig for a flexible appendage (tentacle)
+based on the :doc:`Spline IK </animation/constraints/tracking/spline_ik>` constraint. The IK control bones manage
+control points of a Bezier spline curve, which in turn is followed by the IK chain.
+
+The tentacle can be generated in three major modes:
+
+Stretch To Fit
+   In this simplest mode all bones of the sub-rig deform chain follow the curve and squash & stretch to match
+   its length.
+Manual Squash & Stretch
+   This mode is almost the same, but the chain does not automatically scale to match the curve length.
+   Instead, it tries to cover as much as possible of the curve given its manually scaled length.
+   If the curve is too short, the chain will overhang it and straighten out, but this is not fully stable.
+Direct Tip Control
+   This mode is more similar to the behavior of IK limbs: the final bone of the chain is directly controlled by
+   the tip IK control, while the other bones of the chain stretch and follow the curve to bridge the gap.
+
+The tentacle sub-rig has the following control bones:
+
+Master
+   The tentacle has the same gear master control as other limbs (seen as a line in the images).
+IK Start
+   The IK control at the base of the tentacle, which can be used to control the base twist and sideways scale, and
+   is one of the potential switchable parents for other IK controls.
+
+   In the *Manual Squash & Stretch* mode it controls uniform scale of the tentacle.
+IK Start (Extra) :guilabel:`Optional`
+   Extra start controls, optional and hidden by default. Switchable parents default to the *IK Start* control.
+   The scale of the control may optionally affect the thickness of the chain via the radius of the curve point.
+IK Middle
+   Controls for the middle of the curve. The switchable parents default to *Master*, but may be set to
+   *IK Start* or *IK End* controls.
+   The scale of the control may optionally affect the thickness of the chain via the radius of the curve point.
+IK End (Extra) :guilabel:`Optional`
+   Extra end controls, optional and hidden by default. Switchable parents default to the *IK End* control.
+   The scale of the control may optionally affect the thickness of the chain via the radius of the curve point.
+
+   The *Direct Tip Control* mode adds one more extra end control next to the middle ones that cannot be hidden.
+IK End
+   Controls the last control point of the curve, and is one of the potential parents for the other chain controls.
+
+   In the *Direct Tip Control* mode also directly controls the last bone of the chain.
+IK End Twist :guilabel:`Optional`
+   * *Stretch To Fit*: controls the twist of the tip of the tentacle, interpolated to nothing at the base.
+   * *Manual Squash & Stretch*: also controls the scaling of the tip of the tentacle.
+   * *Direct Tip Control*: does not exist.
+FK Chain :guilabel:`Optional`
+   If enabled, the rig has an alternative fully FK control chain.
+
+The properties panel has the following features:
+
+.. figure:: /images/addons_rigging_rigify_rig-features_spline-properties.png
+   :align: right
+   :width: 200px
+
+Start/End Controls :guilabel:`Optional`
+   If extra controls exist, this property controls how many of them are visible and active.
+
+   When a control is disabled, it is snapped to a position extremely close to the corresponding end control point,
+   thus effectively neutralizing its effect. Thus, changing the setting during an animation can cause jumps.
+
+   The plus and minus buttons can help with maintaining a continuous transition in an animation by keyframing the
+   change in the property value with Constant interpolation, and also snapping and keyframing the control itself
+   to its 'hidden' position.
+
+End Twist Estimate :guilabel:`Optional`
+   In the *Direct Tip Control* mode the twist at the end of the tentacle is deduced from the orientation of the
+   tip control. However, for technical reasons, that is only possible within the 180 degrees range of neutral.
+
+   A long tentacle can accept more twist than 180 degrees, so a workaround is necessary. This property allows
+   specifying an approximate estimate of the twist value, and the rig then applies the automatic correction within
+   180 degrees of this value.
+
+IK-FK, IK<->FK Snapping :guilabel:`Optional`
+   If the FK controls are enabled, these provide standard IK-FK switching and snapping.
+
+   However, unlike other limbs, for this rig automatic IK to FK snapping can only be approximate and requires
+   manual tuning. For this reason, buttons for baking the snapping over a range of keyframes are not provided.
+
+Parent Switch
+   Switches the parent of the active IK control.
+
 
 Head
 ====

manual/addons/rigging/rigify/rig_types/basic.rst

@@ -13,8 +13,8 @@ This is unlike chain-based rig types that usually consume the whole connected ch
 
 .. _rigify.rigs.basic.copy_chain:
 
-``basic.copy_chain``
-====================
+basic.copy_chain
+================
 
 Copies the bone chain keeping all the parent relations within the chain untouched.
 Useful as a utility rig type for custom rigs.
@@ -29,8 +29,8 @@ Deform (Boolean)
 
 .. _rigify.rigs.basic.pivot:
 
-``basic.pivot``
-===============
+basic.pivot
+===========
 
 Single-bone rig type that creates a 'custom pivot' control for rotating and scaling its child sub-rigs.
 
@@ -74,8 +74,8 @@ Deform Bone
 
 .. _rigify.rigs.basic.raw_copy:
 
-``basic.raw_copy``
-==================
+basic.raw_copy
+==============
 
 Single-bone rig type that copies the bone without the ``ORG-`` name prefix.
 
@@ -106,8 +106,8 @@ Relink Constraints
 
 .. _rigify.rigs.basic.super_copy:
 
-``basic.super_copy``
-====================
+basic.super_copy
+================
 
 Single-bone rig type that simply copies the bone. Useful as utility rig type for
 adding custom features or specific deform bones to your rigs.

manual/addons/rigging/rigify/rig_types/face.rst

@@ -8,21 +8,21 @@ These rig types implement components of a modular face.
 
 .. _rigify.rigs.face.basic_tongue:
 
-``face.basic_tongue``
-=====================
+face.basic_tongue
+=================
 
-Generates a simple tongue, extracted from the original PitchiPoy ``super_face`` rig.
+Generates a simple tongue, extracted from the original PitchiPoy :ref:`super_face <rigify.rigs.faces.super_face>` rig.
 
 B-Bone Segments (integer)
    Defines the number of b-bone segments each tweak control will be split into.
 Primary Control Layers
-   Optionally specifies layers for the main control.
+   Optionally specifies bone collections for the main control.
 
 
 .. _rigify.rigs.face.skin_eye:
 
-``face.skin_eye``
-=================
+face.skin_eye
+=============
 
 Implements a skin system :ref:`parent controller <rigify.rigs.skin.skin_parents>` that manages
 two skin chains for the top and bottom eyelids in addition to generating the eye rotation mechanism.
@@ -49,8 +49,8 @@ Eyelids Follow Default
 
 .. _rigify.rigs.face.skin_jaw:
 
-``face.skin_jaw``
-=================
+face.skin_jaw
+=============
 
 Implements a skin system :ref:`parent controller <rigify.rigs.skin.skin_parents>` that manages
 one or more loops of mouth skin chains in response to the movement of jaw and mouth controls.

manual/addons/rigging/rigify/rig_types/faces.rst

@@ -3,8 +3,10 @@
 Faces
 *****
 
-``faces.super_face``
-====================
+.. _rigify.rigs.faces.super_face:
+
+faces.super_face
+================
 
 Will create a face system based on the bones child to the parent that has the property set on it.
 

manual/addons/rigging/rigify/rig_types/index.rst

@@ -1,6 +1,3 @@
-.. _bpy.types.PoseBone.rigify_type:
-.. _bpy.types.RigifyParameters:
-
 #############
   Rig Types
 #############

manual/addons/rigging/rigify/rig_types/limbs.rst

@@ -6,26 +6,32 @@ Limbs
 These rig types handle generation of different kind of limbs and their features, like fingers.
 
 
-``limbs.simple_tentacle``
-=========================
+.. _rigify.rigs.limbs.simple_tentacle:
 
-Will create a bendy and stretchy b-bones tentacle chain or automatic bendy and stretchy finger controls.
+limbs.simple_tentacle
+=====================
+
+Will create a simple bendy and stretchy b-bones tentacle chain, which can optionally replicate local rotation
+from preceeding bones to the subsequent ones for use in cases like fingers.
 
 Requirement: A chain of at least two connected bones.
 
 Automation Axis (X, Y, Z, None)
    Enables the automation on the selected axis. Multiple axis or none can be selected holding :kbd:`Shift-LMB`.
-   When enabled the controls of the last bones will copy the rotations from the previous ones.
+   When enabled the subsequent control bones will copy the local rotations from the previous ones.
    The option is accessible in the controls of the final rig as a Copy Rotation constraint and
    can be disabled even after rig is generated, or at animation time.
 Assign Tweak Layers
-   If enabled, allows placing the Tweak controls on different layers from the main controls.
+   If enabled, allows placing the Tweak controls in different bone collections from the main controls.
 
 
-``limbs.super_finger``
-======================
+.. _rigify.rigs.limbs.super_finger:
 
-Will create a bendy and stretchy chain or automatic bendy and stretchy finger depending on a master control bone.
+limbs.super_finger
+==================
+
+Will create a bendy and stretchy finger chain with a master control bone that controls the rotation of
+all joints through its scale.
 
 Requirement: A chain of at least two connected bones.
 
@@ -39,27 +45,40 @@ IK Control
    IK starts its work with the shape of the finger defined by FK controls and adjusts it
    to make the fingertip touch the IK control. It is designed as a tool to temporarily keep
    the fingertip locked to a surface it touches, rather than a fully featured posing system.
+
+   To improve performance, the switchable parent for the IK control contains only one option beside None.
+   Thus it is advised to add a 'held object' control using the :ref:`basic.raw_copy <rigify.rigs.basic.pivot>`
+   rig to act as the common parent for the fingers with a fully functional parent switch.
+IK Local Location
+   Specifies the value of the Local Location option for IK controls, which decides if the location
+   channels are aligned to the local control orientation or world.
 Assign Tweak Layers
-   If enabled, allows placing the Tweak controls on different layers from the main controls.
+   If enabled, allows placing the Tweak controls in different bone collections from the main controls.
+Assign Extra IK Layers
+   If enabled, allows placing the extra IK control in different bone collections from the main controls.
 
 .. note::
 
-   Rotation Axis (Bend Rotation Axis in the case of ``limbs.super_finger``)
+   Rotation Axis (Bend Rotation Axis in the case of `limbs.super_finger`_)
    affects the :doc:`roll </animation/armatures/bones/editing/bone_roll>` of the generated bones.
    Automatic mode recalculates the generated bones roll while
    any of the Manual modes copy the roll of the meta-rig bones.
 
 
-``limbs.super_limb``
-====================
+.. _rigify.rigs.limbs.super_limb:
 
-A backwards compatibility wrapper around ``limbs.arm``, ``limbs.leg`` and ``limbs.paw``.
+limbs.super_limb
+================
+
+A backwards compatibility wrapper around `limbs.arm`_, `limbs.leg`_ and `limbs.paw`_.
 
 
-``limbs.arm``
-=============
+.. _rigify.rigs.limbs.arm:
 
-Will create a full featured bendy and stretchy arm depending on the user-defined options.
+limbs.arm
+=========
+
+Will create a fully featured bendy and stretchy arm depending on the user-defined options.
 
 Requirement: A chain of three connected bones (upper_arm, forearm, hand).
 
@@ -79,15 +98,17 @@ B-Bone Segments (integer)
 Custom IK Pivot
    Generates an extra control for the end of the IK limb that allows rotating it around an arbitrarily placed pivot.
 Assign FK Layers
-   If enabled, allows placing the FK chain on different layers from the IK bones.
+   If enabled, allows placing the FK chain in different bone collections from the IK bones.
 Assign Tweak Layers
-   If enabled, allows placing the Tweak controls on different layers from the IK bones.
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.
 
 
-``limbs.leg``
-=============
+.. _rigify.rigs.limbs.leg:
 
-Will create a full featured bendy and stretchy leg depending on the user-defined options.
+limbs.leg
+=========
+
+Will create a fully featured bendy and stretchy leg depending on the user-defined options.
 
 Requirement: A chain of four connected bones (thigh, shin, foot, toe) with one unconnected
 child of the foot to be used as the heel pivot.
@@ -104,6 +125,10 @@ Separate IK Toe
    Specifies that two separate toe controls should be generated for IK and FK instead of sharing one bone.
    This is necessary to get fully correct IK-FK snapping in all possible poses.
 
+Toe Tip Roll
+   Generates a slider to switch the heel control to pivot on the tip rather than the base of the toe
+   (for roll this obviously only applies on forward roll).
+
 Rotation Axis (Automatic, X, Z)
    Defines the bend axis for the IK chain. FK chains will have a totally free degree of rotation on all axes.
 Limb Segments (integer)
@@ -113,15 +138,17 @@ B-Bone Segments (integer)
 Custom IK Pivot
    Generates an extra control for the end of the IK limb that allows rotating it around an arbitrarily placed pivot.
 Assign FK Layers
-   If enabled, allows placing the FK chain on different layers from the IK bones.
+   If enabled, allows placing the FK chain in different bone collections from the IK bones.
 Assign Tweak Layers
-   If enabled, allows placing the Tweak controls on different layers from the IK bones.
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.
 
 
-``limbs.paw``
-=============
+.. _rigify.rigs.limbs.paw:
 
-Will create a full featured bendy and stretchy paw depending on the user-defined options.
+limbs.paw
+=========
+
+Will create a fully featured bendy and stretchy paw depending on the user-defined options.
 
 Requirement: A chain of four or five connected bones (thigh, shin, paw, *optional* digit, toe).
 
@@ -138,15 +165,17 @@ B-Bone Segments (integer)
 Custom IK Pivot
    Generates an extra control for the end of the IK limb that allows rotating it around an arbitrarily placed pivot.
 Assign FK Layers
-   If enabled, allows placing the FK chain on different layers from the IK bones.
+   If enabled, allows placing the FK chain in different bone collections from the IK bones.
 Assign Tweak Layers
-   If enabled, allows placing the Tweak controls on different layers from the IK bones.
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.
 
 
-``limbs.front_paw``
-===================
+.. _rigify.rigs.limbs.front_paw:
 
-Derivative of ``limbs.paw`` with extended IK suitable for use in front paws.
+limbs.front_paw
+===============
+
+Derivative of `limbs.paw`_ with extended IK suitable for use in front paws.
 The additional IK limits the degree of change in the angle between shin and
 paw bones (2nd and 3rd) as the main IK control moves and rotates.
 
@@ -158,18 +187,22 @@ Heel IK Influence
    not affect the rotation of the paw bone, while lower values provide some blending.
 
 
-``limbs.rear_paw``
-==================
+.. _rigify.rigs.limbs.rear_paw:
 
-Derivative of ``limbs.paw`` with extended IK suitable for use in rear paws.
+limbs.rear_paw
+==============
+
+Derivative of `limbs.paw`_ with extended IK suitable for use in rear paws.
 The additional IK tries to maintain thigh and paw bones (1st and 3rd) in a nearly parallel orientation
 as the main IK control moves and rotates.
 
 For best results, thigh and paw bones should start nearly parallel in the rest pose.
 
 
-``limbs.super_palm``
-====================
+.. _rigify.rigs.limbs.super_palm:
+
+limbs.super_palm
+================
 
 Will create a palm system based on the distance between palm bones.
 
@@ -182,3 +215,51 @@ Both Sides
 
 Primary Rotation Axis (X, Z)
    Defines the automatic rotation axis to be used on the palm bones.
+
+
+.. _rigify.rigs.limbs.spline_tentacle:
+
+limbs.spline_tentacle
+=====================
+
+This rig type implements a flexible tentacle with an IK system using the Spline IK constraint. The control bones
+define control points of a Bezier curve, and the bone chain follows the curve.
+
+The curve control points are sorted into three groups: start, middle and end. The middle controls are always
+visible and active, while the other two types can be shown and hidden dynamically using properties; when enabled
+they appear next to the corresponding permanent start/end control and can be moved from there.
+
+Extra Start Controls
+   Specifies the number of optional start controls to generate.
+Middle Controls
+   Specifies the number of middle controls to generate.
+Extra End Controls
+   Specifies the number of optional end controls to generate.
+Tip Control:
+   Specifies how the curve stretching and the final control bone work:
+
+   Stretch To Fit
+      Stretches the whole bone chain to fit the length of the curve defined by the controls.
+
+      An end twist control is generated to control the twist along the chain.
+   Direct Tip Control
+      Generates an IK end control, which directly controls the final bone of the chain similar to how
+      regular IK works for limbs, as well as controlling the end of the bezier curve. The middle bones of
+      the chain stretch to follow the curve and cover the gap.
+
+      The rig automatically deduces twist of up to 180 degrees based on the orientation of the end control.
+      Higher amounts of twist have to be dialled in through an End Twist Estimate slider to avoid flipping.
+   Manual Squash & Stretch
+      This mode allows full manual control over the chain scaling, while the chain covers as much of the curve
+      as it can given its current length.
+
+      The start control of the chain manages its uniform squash & stretch scale, while the end twist control
+      manages both the twist of the chain, as well as its scale at the tip (blended gradually along the length).
+Radius Scaling
+   Allows scaling the controls to control the thickness of the chain through the curve.
+Maximum Radius
+   Specifies the maximum scale allowed by the Radius Scaling feature.
+FK Controls
+   Generates an FK control chain and IK-FK snapping.
+Assign FK Layers
+   If enabled, allows placing the FK chain in different bone collections from the IK bones.

manual/addons/rigging/rigify/rig_types/skin.rst

@@ -65,8 +65,8 @@ Custom Rigging
 
 .. _rigify.rigs.skin.basic_chain:
 
-``skin.basic_chain``
-====================
+skin.basic_chain
+================
 
 This is the basic chain rig, which bridges controls with B-Bones but does not add
 any automation to the controls themselves.
@@ -107,8 +107,8 @@ Chain Priority
 
 .. _rigify.rigs.skin.stretchy_chain:
 
-``skin.stretchy_chain``
-=======================
+skin.stretchy_chain
+===================
 
 This rig extends the basic chain with automation that propagates movement of the start and end,
 and an optional middle control, to other controls. This results in stretching the whole chain
@@ -134,9 +134,9 @@ Propagate to Controls
    Allows other chains to see propagated twist and scale via *Merge Parent Rotation and Scale* when their
    controls are merged into this chain, instead of it being completely local to this chain.
 Primary Control Layers
-   Optionally specifies layers for the end controls.
+   Optionally specifies bone collections for the end controls.
 Secondary Control Layers
-   Optionally specifies layers for the middle control, falling back to *Primary Control Layers* if not set.
+   Optionally specifies bone collections for the middle control, falling back to *Primary Control Layers* if not set.
 
 The main controls with active falloff have the effect of *Merge Parent Rotation and Scale*
 automatically enabled just for them.
@@ -144,8 +144,8 @@ automatically enabled just for them.
 
 .. _rigify.rigs.skin.anchor:
 
-``skin.anchor``
-===============
+skin.anchor
+===========
 
 This rig effectively acts as a zero-length chain with highest priority,
 ensuring that it becomes the owner when merging controls with other chains.
@@ -168,10 +168,10 @@ Orientation
 
 .. _rigify.rigs.skin.glue:
 
-``skin.glue``
-=============
+skin.glue
+=========
 
-This rig is in concept similar to ``skin.anchor``, but instead of overriding controls,
+This rig is in concept similar to `skin.anchor`_, but instead of overriding controls,
 it is used to read or adjust the state of controls generated by other rigs.
 The head of the bone must overlap a control of another skin rig.
 
@@ -210,8 +210,8 @@ Add Constraint
 
 .. _rigify.rigs.skin.transform.basic:
 
-``skin.transform.basic``
-========================
+skin.transform.basic
+====================
 
 This rig provides a simplistic :ref:`parent controller <rigify.rigs.skin.skin_parents>`, which uses regular
 translation, rotation, or scale to modify locations but not orientations or scale of its child chain controls.

manual/addons/rigging/rigify/rig_types/spines.rst

@@ -6,12 +6,17 @@ Spines
 These rigs are used to generate spine structures, including the head and tail.
 
 
-``spines.super_spine``
-======================
+.. _rigify.rigs.spines.super_spine:
+
+spines.super_spine
+==================
 
 Will create a complete bendy and stretchy b-bones spine system based on bone numbers of
 your bone chain and user defined options.
 
+This is a composite wrapper of `spines.basic_spine`_, `spines.super_head`_ and `spines.basic_tail`_.
+Note that for the tail, the direction of the bones is reversed compared to the separate rig.
+
 Requirement: A chain of at least three connected bones (base system).
 
 .. figure:: /images/addons_rigging_rigify_rig-types_spines-required.png
@@ -31,7 +36,10 @@ Tail (Boolean)
 
    Tail Position (integer)
       Defines the bone where the tail system starts. The next bone will always be the hips system.
-
+X, Y, Z (Boolean)
+   When generating a tail, specifies which local axis rotations should be replicated along the chain.
+Assign Tweak Layers
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.
 
 .. figure:: /images/addons_rigging_rigify_rig-types_spines-default.png
 
@@ -40,3 +48,45 @@ Tail (Boolean)
 .. figure:: /images/addons_rigging_rigify_rig-types_spines-example.png
 
    Spine with tail bones.
+
+
+.. _rigify.rigs.spines.basic_spine:
+
+spines.basic_spine
+==================
+
+Defines a bendy and stretchy b-bones spine.
+
+Pivot Position (integer)
+   Defines the pivot position for torso and hips.
+Assign Tweak Layers
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.
+FK Controls
+   Specifies whether to generate an FK control chain.
+Assign FK Layers
+   If enabled, allows placing the FK chain in different bone collections from the IK bones.
+
+
+.. _rigify.rigs.spines.basic_tail:
+
+spines.basic_tail
+=================
+
+Defines a bendy and stretchy b-bones tail.
+
+X, Y, Z (Boolean)
+   Specifies which local axis rotations should be replicated along the chain from each control
+   bone to the following one.
+Assign Tweak Layers
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.
+
+
+.. _rigify.rigs.spines.super_head:
+
+spines.super_head
+=================
+
+Defines a head rig with follow torso controls.
+
+Assign Tweak Layers
+   If enabled, allows placing the Tweak controls in different bone collections from the IK bones.

manual/editors/nla/editing.rst

@@ -63,6 +63,7 @@ Duplicate
 .. reference::
 
    :Menu:      :menuselection:`Edit --> Duplicate`
+   :Shortcut:  :kbd:`Alt-D`
 
 Creates a new instance of the selected strips with a copy of the action.
 
@@ -75,15 +76,14 @@ Linked Duplicate
 .. reference::
 
    :Menu:      :menuselection:`Edit --> Linked Duplicate`
-   :Shortcut:  :kbd:`Alt-D`
+   :Shortcut:  :kbd:`Shift-D`
 
 The contents of one Action strip can be instanced multiple times. To instance another strip,
 select a strip, go to :menuselection:`Edit --> Linked Duplicate`.
 It will uses the same action as the selected strips.
 
 Now, when any strip is tweaked, the others will change too.
-If a strip other than the original is tweaked,
-the original will turn to red.
+If a strip other than the original is tweaked, the original will turn to red.
 
 .. figure:: /images/editors_nla_editing_linked-strip-edit.png
 

manual/modeling/geometry_nodes/inspection.rst

@@ -116,3 +116,12 @@ to make detecting that situation easy.
 
 The same data is also available in the :ref:`geometry-nodes-internal-dependencies` panel
 in the modifier's UI.
+
+Geometry Randomization
+======================
+
+Many nodes don't guarantee the order of elements in which they output things. For example, the order of edges coming out of the `Triangulate` node is deterministic but not well defined. The order may change between Blender versions. Therefor, if node setups depend on a specific order, they may break when the Blender implementation changes. Changing the order can often be necessary in order to fix bugs or improve performance.
+
+"Geometry randomization" can be temporarily enabled to see if a .blend file depends on the indices in unstable ways. When enabled, various internal algorithms shuffle the result geometry elements so that any dependence on it would not work anymore. When building setups that are supposed to last a long time, it is recommended to check if they still work with randomization enabled.
+
+To enable it, first enable `Developer Extras` in the :doc:`preferences </editors/preferences/interface>`. Then :doc:`search </interface/controls/templates/operator_search>` for `Set Geometry Randomization`. The popup allows enabling and disabling the randomization.