The Many Layers of Animation - Using Animation Layers to Enhance Your Work
There are moments in animation when the direction of the story must change, which often can affect something as minor as a pose, or on a larger scale, an entire sequence of animation. Since this is common, animation layers were introduced in software like Maya, 3ds Max, MotionBuilder and CINEMA 4D, to provide animators with a way of changing their work on the fly in order to create a variety of alternative options for their characters' performances.
Also known as takes, according to the direction they've been given by their higher-ups, until the best option for the story was chosen. This robust and innovation system was known as animation layers. In this article, you'll get a close look into animation layers and learn not only what they are, but, more importantly, you'll understand how useful they can be in an animation pipeline.
Typically, there are two forms of animation layers: relative and absolute (also know in other software as additive and override). They both are similar in that they allow you to change an animation in a non-destructive way, meaning your original animation would be unharmed by changes made to either layer, yet they also have vast differences that are worth noting. Let's first have a look into what relative animation layers are.
Animation without a Relative Layer
Animation with a Relative Layer
(The shake was added with an Expression that was connected to the Relative Layer)
Relative or Additive, Animation Layers allow animators to build on top of what they have already animated. Essentially, they allow you to exaggerate the result of your original animation. An example as to when a Relative Layer could be used is if your character needed to jump a little higher, or if its pose needed to be pushed further for a stronger and more appealing silhouette. Changes like these can be made without worry, because your original work is stored in what is known as the Base Layer, which stores all of your original keyframes.
What this means is that if, for any reason, you or your team lead decides that the changes to the performance or takes aren't quite working out, all you would need to do is simply trash the layer or layers in which those extra keys are stored and you'll be back where you left off. This type of non-linear workflow is ideal because it gives you the opportunity to work very flexibly.
Animators can experiment with various styles or outcomes of their work, and if the changes work they can choose to either keep those changes in their layers, or to bake the changes into the original animation, which might be required if the animation must later be exported for use in either a game engine or to another software for cross-platform pipelines.
Animation without an Absolute Layer
Animation with an Absolute Layer
(In this example, the arms were changed)
Unlike Relative Layers that allow you to add on top of animation, Absolute, or Override Layers are used when an entire idea must change. Absolute layers block incoming keyframes from the Base Layer, allowing animators to create takes that have absolutely nothing to do with their original animation.
When can this come in handy? Well, take the example of a space ranger battling a dangerous force of alien mechs. Let's say the original animation involved the space ranger fending off the aliens, which are probably three or four times his size, with a spork (that's a spoon and fork combo).
Though sporks are awesome, it'd be safe to assume they probably wouldn't be much help against an alien invasion. So, at this moment, the decision could be made to create an entirely new take with an Override layer that swaps the rangers awesome spork with an even MORE awesome plasma cannon.
See the possibilities now? And just like Relative Layers, this Absolute Layer can then remain in its own layer, in case the decision is made to revert back to the original performance, or baked into the original animation, which in this case, would change all keyframes. Either way, both types of layers allow you to work in non-destructive and non-linear ways, so that you can work as flexibly as possible.
To conclude, Animation Layers allow animators to make changes to their work without having to interfere with their original keyframes, thus making the system truly invaluable, especially in pipelines that call for changes to be made constantly.
Whether you desire to exaggerate your original performance with a Relative Layer or change your idea entirely with an Override Layer, you can still find comfort in the fact that you can "take it or leave it" with Animation Layers without ever having to worry about damaging the hard work you put into your character's original performance.
You also have the option of implementing a hybrid layering workflow that uses both types, so you can push your creativity beyond its limits without restraint. So make sure to familiarize yourself with your software's Animation Layering system if you haven't already. One day, it might save you from having to defend yourself against an alien invasion with just a spork. To learn more about the power of animation layers be sure to check out the Animation Layers in Maya tutorial.