In part 1, I described a workflow that you can use to retarget a pre-made animation onto another character using HumanIK. Now, I will discuss how you can modify the animation using animation layers. Previously, I mentioned there are some differences in the workflow between Maya and Maya LT. I will explain those differences as we move forward.
By now, you have your original animation applied to your character. However, maybe the animation doesn’t exactly fit your needs, and you would like to change it a little. At this point, you end up using animation layers a lot. For example, if your resulting animation features a character that is “floating” above the Y=0 plane, and/or is not centered, you can fix the issue by using an animation layer to move the character back into position.
This is where the first difference between Maya and Maya LT come into play. In Maya, you can “reference” a scene, meaning you can “reference” your scene with your pre-made character instead of actually importing it. This also results in cleaner scenes since you are not adding any kind of extra data to your final character’s scene (no extra HIK nodes, no left overs, etc.). This is a really cool feature missing in Maya LT, and it forces you to import the pre-made animation.
If you think you need to modify the animation because it’s not exactly what you want, you can also use animation layers to modify it. The animations I get from are rarely 100% what I am looking for, so I end up modifying them all the time (sometimes I only make small adjustments, but sometimes I make heavy modifications). This is not to say Mixamo’s animations are not good. They are definitely good, but sometimes they may not 100% fit what I need. For example, the following video shows an animation I got from Mixamo.
And this is the resulting animation.
The reason I got that animation instead of creating an animation from scratch is simple: using a pre-made animation gave me the mechanics of locomotion right from the start, making it easier to create a believable animation.
Depending on your workflow and how much you may need to modify an animation, you may end up creating a lot of animation layers. If you were using Maya, not Maya LT, this wouldn’t be an issue. While I am not sure how many animation layers you can create in Maya, I’ve created up to 10 for a single character. However, in Maya LT you can only create two (a base layer + two extra layers for your modifications). This is definitely something that may make things a lot harder for you in some situations, and I have to say I am not a fan of this limitation.
To circumvent that, I have end up doing two things. First, I try to cram as many adjustments and modifications per layer as possible. For example, I won’t create a layer just for “offset adjustment” (re-centering a character) as I described above, but rather, I will add other things too, like general posture changes, movement adjustments (for example, fixing a position a hand reaches). That way, when I need the second layer, I can use it for final adjustments.
Just like before, when everything is ready, I bake the animation to the bones, delete the unneeded nodes (as explained before), and then export into Unity.
Using pre-made animations to drive your characters in Maya (and ultimately Unity) is very easy in Maya LT. You just need to keep in mind a few things when you are doing it, to avoid problems with the final product.