There are two modes for animation layers that affect how MotionBuilder calculates Rotation animation: Per Layer and Per Channel. See also Setting the animation layer modes.
When you animate an object’s rotation, you set keyframes for three properties; Rotation X, Rotation Y, and Rotation Z. The Layer Accumulation modes let you choose in which order MotionBuilder calculates these properties, as shown in the following table.
| Option | Description |
|---|---|
| Per Layer | The keyframes set for rotation are calculated according to layer first, and property second. MotionBuilder calculates all the keyframes set for these three properties (Rotation XYZ) on the first layer before calculating the next layer, and so on. |
| Per Channel | The keyframes set for rotation are calculated according to property first, and layer second. All keyframes set for Rotation X are calculated first for every layer, then all keyframes set for Rotation Y on all layers are calculated, and finally all keyframes set for Rotation Z on all layers are calculated. |
MotionBuilder and Maya use different Layer Accumulation modes by default. In MotionBuilder, Per Layer (known as Quaternion Rotation Accumulation mode in Maya) is the default. In Maya, Per Channel (known as Euler Rotation Accumulation mode) is the default.
MotionBuilder does not support layers that use the Scale Additive Accumulation mode. A dialog warning appears when you import a scene that uses this type of layer. You can either use Scale Multiply Accumulation mode in Maya and export the file again or you can bake your layers to retain the visual fidelity of your animation.
