The NLA Editor was originally designed only to work with armatures. In recent versions of Blender, we now have the option to add shape key actions (like the lip sync action) to the NLA Editor, but it's not as straightforward as with armatures.
Note that down in the NLA Editor, the Plane (the name of the character mesh, since that's what it started as and we never renamed it) has a row. I've kept the name "Plane" to remind us of how far we've come! (If you want to rename it, use the OB: text box in the Link and Materials panel, under the Edit buttons, or, the Object and Links panel under the Object buttons).
Press C to create a strip from the lip sync action.
A strip is created, but it's only a placeholder for now. It's a single frame long and it's actually BEFORE frame 1. We have to change some settings to let the NLA Editor know we want this lip sync action to be a strip.
Note that there are no keys in the Lip sync channel right now.
Change a window to the IPO Curve Editor. I changed the Action window into an IPO Curve editor.
In the IPO Curve Editor, change the IPO Type to shape.
The "Plane", or the character mesh, now has a row in the NLA.
Converted the lip sync action to a strip . . .
Switch to the IPO Curve Editor.
In the IPO window, change the IPO type to
Shape
Several curves appear. These curves are another way of
visualizing the keys we added for the lip sync. The X-axis of the IPO window is time, or frames. The Y-axis of the IPO window reflects the slider setting, or how strong the shape is activated.
Each curve is for a different shape, and they are color-coded. The dots on the curves are the actual keys.
If you compared the IPO window with the Action Editor, you'd find that the frame number of each dot in the IPO curves matches the frame number of each key in the Action Editor. Both views are useful.
You can fine-tune the animation through the IPO curves. RMB to select a curve, and TAB to enter the curve's edit mode, where you can adjust the shape of the curves. This is where you have the finest control of the keyframes in the animation, and is often the place to go for really fine-tuning an animation.
For now, we're going to leave the IPO curves alone, but before we leave the IPO window:
Click the button next to the IPO Type menu (I'm actually not positive what the tool tip actually means, but I know this is what needs to be done for everything to work).
Note that there are now keys visible in the NLA Editor for the Lip sync action, and the NLA strip returned to its true length.
NLA Strips for shape keys: In summary, in order to add shape key actions to the NLA Editor, you have to:
Select the Action in the Action Editor 1.
Open an IPO Window 2.
Switch to the Shape IPO type from the menu 3.
Click the button next to the IPO Type menu to allow the IPO curves to be used in the NLA
4.
Important: Go back to the NLA Window and make sure NLA mode is activated for both Armature and Plane.
Important: Select the armature and turn off Rest Position
Press Alt A in the 3D Window to view the animation. The character walks AND talks!
Now what happens if we want to adjust where in the walkcycle he says the words? We can easily slide the Lip sync strip where we want it, but the sound won't follow. The sound strip is not in the NLA, it's in the Sequence Editor. Slightly confusing, and future versions of Blender may change this. For now, we have to do things by the numbers.
The IPO window, with shape curves.
Click the button as shown to include the IPO in the Action.
Note the Lip sync channel in the NLA now has keys visible.
Select the Lip sync strip in the NLA Editor and press N to bring up the Strip Properties panel (if it's not already visible).
Take note of how long the strip is: Action Start is 1, and Action End is 22, so the strip is 21 frames long. Strip Start and Strip End are currently the same, but we're about to change that.
We need the frame to start on an integer, because a limitation of the
Sequence Editor is that we can only start the sound clip on an integer frame.
One way to do this is to move the NLA strip for the Lip sync with G , and then round the Strip Start: and Strip End: number boxes down. I moved the strip to 50.42 (and it went to 71.42) then I typed in the Strip Properties the Strip Start: 50 and Strip End: 71.
Switch to the Sequence Editor.
Select the sound clip with RMB and move it with G .
Move the sound clip so it starts on the same frame as you typed in for the Strip Start in the previous step (I moved it to frame 50).
Play the animation - the sound and lip sync should now occur at frame 50.