- Phrasing improvements.
- Add screenshots.

@@ -5,70 +5,111 @@
 Actions
 *******

@@ -7,3 +7,2 @@
 
-When animating objects and properties in Blender, Actions record and contain the data.
-As everything else in Blender, Actions are data-blocks.
+*Actions* are Blender's container for animation data.  For example, when you animate the location of an object, that animation is stored in an action rather than directly on the object itself.  The object then uses the action to get animated, much the same way that a mesh uses a material to get shaded.  All animatable data-blocks (objects, meshes, materials, etc.) are animated this way: they don't store their own animation data, but instead use an action that stores the animation data for them.

@@ -14,3 +14,2 @@
 
-So when you animate an object by changing its location with keyframes,
-the animation is saved to the Action.
+The animation data inside an action is further organized into *Slots*.  Each action has a set of slots and different animation data for each of those slots.  An animated data-block then specifies both which action it uses and also which slot within that action it uses, and that determines which animation data the data-block is animated by.

@@ -10,3 +9,3 @@
 
-.. figure:: /images/animation_actions_data3.png
+The benefit of this approach is that animation data can be flexibly organized and reused.  For example, if you're building a library of animations (run cycles, jumps, idling, etc.), each animation can go into its own action, which can then be linked or imported into other files to be reused as needed.
 

@@ -22,0 +43,4 @@
+Slot Names and Associated Types
+-------------------------------
+
+Each slot in an action has a name.  You can set these names however you like, but by default slots are named after the data-block they were initially created for.

@@ -22,0 +47,4 @@
+
+In addition to having a name, each slot also has an associated data-block type that it is intended for (for example, "material", "object", etc.).  This is set automatically when a slot is first assigned to animate a data-block.
+
+In the action editor's channel list you can see the associated type of each slot displayed as an icon next to its name.

@@ -22,0 +53,4 @@
+
+   Slots displayed in the :doc:`Action Editor's </editors/dope_sheet/modes/action>` channel list, with their associated type as an icon.
+
+A slot must have a unique combination of name + associated type within its action.  For example, you can have two slots named "Cube" in an action as long as one of them is for objects and the other is for materials, but not if they are both for objects.

@@ -42,2 +75,3 @@
+   The :doc:`Dopesheet Editor's </editors/dope_sheet/introduction>` channel list, with the animated channels of various bones grouped under their bone names.
 
-.. _actions-workflow:
+Channels also support a limited form of organization called "channel groups".  For example, by default Blender creates a channel group for the channels of each bone.  These groups are purely for your convenience and have no impact on how Blender interprets the channels.

@@ -50,2 +83,3 @@
 
-   The Action data-block menu.
+.. note::
+   The full heuristics Blender uses to find an appropriate action are beyond the scope of this manual, but can be summarized as: look for actions on closely related attached data-blocks.  For example, if a camera object is already animated and you're now inserting keys for its fov (which lives on the camera data, *not* the camera object), the action the object is using will be reused for the camera data as well.  For more details on these heuristics, see **TODO**.

@@ -56,3 +90,1 @@
-*Actions* can be managed with the *Action data-block menu*
-in the Dope Sheet :doc:`Action Editor </editors/dope_sheet/modes/action>` header,
-or the Sidebar region of the :doc:`NLA Editor </editors/nla/sidebar>`.
+Rather than letting Blender automatically choose an action and slot for a data-block, you can also manually assign them.

@@ -60,3 +92,1 @@
-If you are making multiple actions for the same object,
-press the shield button for each action.
-This will give the actions a *Fake User* and will make Blender save the unlinked actions.
+In the properties of each data-block there is an Animation panel with action and slot selectors.  You can use these to assign actions and slots to a data-block.

@@ -61,3 +92,2 @@
-press the shield button for each action.
-This will give the actions a *Fake User* and will make Blender save the unlinked actions.
+In the properties of each data-block there is an Animation panel with action and slot selectors.  You can use these to assign actions and slots to a data-block.
 

@@ -67,0 +105,4 @@
+
+   When selecting a slot for a data-block, you won't necessarily see all the slots of an action listed in the dropdown.  This is because Blender limits that dropdown to the slots with an associated type that matches the data-block.
+
+When you select an action to animate a data-block, for convenience Blender will also attempt to automatically select an appropriate slot for you based on name and associated type.  If no appropriate slot is found, the slot selector will remain empty.