Switch layer interpolation with mesh warp image layers

[Greenlaw]

Coincidentally, last week I was asked to create lips sync animations using Interpolate Sub-layers, and I used a Mesh Warp for a happy/sad Smart Bone Dial that could change the character's emotion during the dialog. The result looked surprisingly good!

The trick with the Mesh Warp was to add a reference copy of the mesh layer in every mouth shape group inside the Switch layer, and to give each reference layer a unique name related to its group. For example, the mesh for the 'A-I' mouth shape was called 'REF mesh (A-I)', and so on. This makes it clear to Moho that you want the mouth shape artwork layers in a group to use that specific mesh layer inside its group. (Moho can get confused if you don't do this.) When this is set up correctly, you should see only a single mesh reference layer in the Smart Warp Layer selection list.

The 'master' or original mesh layer can reside outside of the Switch layer, and this is the layer you should edit for global changes to all of the mouth shapes in the Switch. You can animate this layer using a Smart Bone Dial.

One cool thing about using the Mesh Warp in my project was that it could be set to affect only the mouth outline and cheek lines and not affect the teeth or tongue layers. Not only did I not want these layers to be warped, they needed to be able to slide independently for a parallax effect whenever the character turned its head.

One limitation I found with using Interpolate Sub-layers is that Moho does not allow you to use Bezier handles to adjust the timing curves between the keyframes for the mouth shapes. When using Interpolate Sub-layers, the only options we have in the timeline are Smooth or Linear, and to duplicate a keyframe to hold it. That's it.

I think this is because a Switch layer is normally meant to Step between drawings and interpolation isn't used for that, and the Graph Editor probably hasn't been updated yet to recognize the Interpolate Sub-layers mode.

Luckily, I was able to complete my work with this limitation just fine, but it would be good to be able to adjust the timing curves between interpolating shapes more precisely in a future release of Moho.

[chucky]

Yes, reference layer makes it work.
It's a good hack.