Retargeting in 3D animation

01/02/2024

LT;DR Animation Retargeting is a functionality enabling the reuse of animations across characters employing identical Skeleton assets yet displaying varying proportions. This process safeguards animated skeletons from losing their proportional integrity or undergoing unnecessary distortions when employing animations across characters with differing shapes. Additionally, Animation Retargeting facilitates the sharing of animations among characters utilizing distinct Skeleton assets, provided they possess a similar Bone Hierarchy and employ a common asset, known as a Rig, to transfer animation data between Skeletons.

How Does Retargeting Work?

Animations are linked to a Skeleton asset, which essentially comprises a list of bone names and hierarchy data. Moreover, this asset retains the initial proportions derived from the original Skeletal Mesh, storing this information as bone translation data. It’s crucial to highlight that the retargeting system exclusively adjusts the bone’s translation component, while the bone’s rotation always originates from the animation data. Since the initial Skeletal Mesh determines the proportions of the Skeleton asset, any other Skeletal Meshes utilizing that same asset but with differing proportions (such as a mesh significantly shorter than the original) necessitate retargeting for proper functionality. Otherwise, Skeletal Meshes with varied proportions would attempt to utilize the translation data from the original mesh, resulting in errors similar to those encountered at the document’s outset.

Retargeting Animations for Different Skeletons

The procedure for managing Animation Retargeting among characters lacking identical Skeleton assets involves allocating a distinct asset known as a Rig. This specialized asset facilitates the transfer of animation data from one Skeleton to another. The Skeleton assets linked to each character establish communication with the shared Rig asset, enabling the accurate transmission of transformation data from a source to its designated target.

Retargeting in Mootion

The generated animation files in Mootion can be applied to other 3D softwares such as Blender, Unity, Unreal Engine, Maya, iClone, Character Creator etc.

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