Doc:2.6/Manual/Animation/Techs/Armatures/Mocap

Page status (reviewing guidelines) Partial page Images needs Proposed fixes: none

Animating armatures with Motion Capture

Motion capture (Mo-cap for short) is the process of recording the movement of objects or people. It is used in military, entertainment, sports, medical applications, and for validation of computer vision and robotics. In filmmaking and video game development, it refers to recording actions of human actors or movements other objects, and using that information to animate digital character models or objects in 2D or 3D computer animation.

In Blender motion capture data is used with motion tracking technique and Motion Capture Tools addon.

With the motion capture process is tracked:

• movements of one or more actors or of other objects;
• real camera movements;
• some camera or object motion path.

This motion capture data may be received in real-time or from already captured footage.

Then, this data is mapped either to:

• 3D model (character or others) or
• virtual 3D-camera,

so that the model (virtual camera) performs the same actions or moves as the actor or real camera.

This process may be contrasted to the older technique of rotoscope.

Blender also oneself supports importing mocap data in the BVH (Biovision Hierarchy) and MHX (Makehuman Exchange) format. Importing is accomplished through a script: File > Import > Motion Capture (.bvh). When you select a BVH file, the script automatically generates an Armature object (bone rig) with the bone names and hierarchical relationships in the BVH file. The animation is stored independently as an Action (block of animation keyframe data) that is automatically assigned to the rig. In order for retargeting to work well, the new target rig should have the same relationships as in the BVH rig.

The motion tracking system is working on a base of 2D footage and solving captured motion data in 3D. Then, this data with Camera Solver, Object Solver and Follow Track constraints mapped on need a camera, object or character in order to follow this captured motion data.

The using external motion capture data in Blender is performs by Motion Capture Tools addon. At the heart of its system, is the retargeting tool, which allows artists to transfer animations from the imported mocap armature to their own rig.

See also

Motion Capture Tools

Motion tracking