What are animation layers? Animation layers allow you build animation on top of existing animation without changing or altering the original animation or keys. Animation layers are conceptually similar to layers in Photoshop. In Photoshop, when constructing or editing an image you create layers, on each layer you add a new detail or aspect. The combination of layers creates the final image. The main difference is with Maya, rather than working with a single still image, animators are working with moving sequences, so the level of complexity is greater.
How Do Animation Layers Work?
Animation layers can be used to create and blend new animation on top of existing animation or they can be used to organize your animation by placing animation of separate objects, controllers or actions on their own layer.
Each animation layer you create holds animation for the entire scene. Each layer has its own keys in the time slider and curves in the graph editor, independent of the other layers.
For example: Let's say I take the scene I've been animating to my supervisor or feedback and approval. After meeting with my supervision I need to make changes to my animation. Rather than remove or delete keys that I have already set (which could get messy very quickly) I could use animation layers to animate on top of what I already have animated. This allows me to preserve my original animation and make my alterations on a separate layer on top of it. The power of animation layers is that it will blend the two together.
Where to Find Animation Layer in Maya
To access animation layers click on the Anim tab next to the Display layer tab.
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Display Layer Tab | Animation Layers Tab |
Button Breakdown
 | Create Layer from Selected- Select the object or controllers you want to create an animation layer for and click this button. This will create an empty animation layer with these objects already added to the layer (there will be no keys on the the timeline and layer in the graph editor for holding new animation curves). A layer called base animation will also be created, this layer will contain an existing animation you have created so far. By default when a layer is create it will be names AnimLayer#, to rename the layer, simply double click and type in a new name. |
 | Create Empty Layer - the will create an empty animation layer that does not contain any objects or controls. To add objects or controllers you want to animation, right click on the layer and select add selected objects. |
 | Move Selection Up in the List, Move Selection Down in the List- the buttons are used to move layers up or down in the list. |
 | Mute Layer- If you want to see the difference between the changes on the animation layer and the original (or other layers) you can mute the layer and the animation contained on the layer will be turned off. |
 | Lock Layer- locks the layer, you cannot make alterations to the layer when it is locked (I tend to lock my Base Animation Layer so I don't accidentally animate on it). |
 | Zero Key- The zero key is for when you want a pose on an Animation Layer to match the Base Animation. Select the control(s) and click this button it will match the exact position from the base layer. |
Layer Weights
We can control how much weight each layer has. The default weight is 1 (100%) how much weight each layer has determines how much of its animation plays in the scene. Use the slide bar at the bottom of animation layers menu to adjust the amount of weight for the entire layer. As an added benefit you can also key the weight to vary how strongly the animation on the layer appears. To key the weight click the K button.
(note: the easiest way to delete the keys on the weight for a layer keys is in the graph editor).
 | Zero Weight and Key Layer- will key the weight on the layer at 0. |
 | Set Weight to One and Key Layer- will key the weight on the layer at 1. |
Layer Types
There are two types of animation layers: additive and override.
To change the layer type. Right Click on a layer > Layer Mode
Additive-adds and blends the keyed attributes with the layer below it. (1+1=2). By default all layers will be in additive mode.
Override- overrides the keyed attributes of any layer below it.
When you set the layer to override mode, you also have an additional option called "passthrough" that you can turn on or off. If passthrough is off then an override layer prevents any animation from layers below it getting through for the object/controls on the layer. If passthrough then animation from layers below is can get through you can control how much animation from the layer below gets through by controlling the layer's weight.
If you want to preserve part of the base layer animation you can key the override layers weight to 0 and set the weight 1 when you want to wipe out (override) a section of animation and animate it a new. You can also use the Zero Key to match poses for particular frames.
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