The Pipeline

Motion Capture Pipeline

To fully understand the process of motion capture, this page outlines a very brief overview of the pipeline from start to finish.

Pre-Production

Storyboard development & Shot analysis

It is important to work out exactly what action is needed at this stage, plus any restrictions which may impede the actor. There are several factors which need to be addressed:
- Does the actors size correspond to that of the character.
- Should the actor have any props, or costume (for example having the actor where horns for your demon character in your mocap session, will prevent the arms going through the horns at the implementing stage) The spatial surrounding should be a factor.
- Will the motion need to be blended (e.g. A running motion, as the motion capture studio will only capture a fragment of the run).

Character Rigging

Develop a character rig, which involves the following:

- Matching the actor's size as much as possible.
- Constraining the joints.
- Problems may include exporting out of your animation package into the correct format (e.g. .xsi into fbx) Several different export formats should be tested to realize which suites best with the character rig (e.g .bvh, .fbx, etc).

Actual Motion Captured

-This can be viewed on a rig in real time. There are several different forms of Motion Capture devices. The most commonly used are:
Mechanical, Optical, and Electromagnetic (magnetic)


A recent MoCap session at Bournemouth University

Cleaning Data

- This involves several data manipulators being applied to the motion capture data. In optical motion capture systems, for example, after you capture the movements of your actors, the data is stored as raw 2D data. ‘Reconstruction’ process will convert it into continuous 3D trajectories. ‘Label’ process will label all the trajectories and so on. Additional processing may be needed when there are data gaps , jitters and other data-noises.

Implementing data

- This is simply the process of applying your data to your skeleton rig provided at the initial stages. There can be several problems at this stage depending on the formats and animation package chosen. For example there is issues with UVs, materials, scaling etc. It is suggested you follow each package pipeline to minimize these issues.


Motion builder, one of the applications used to blend, clean and apply MoCap data.

Origins Marey Muybridge Fleischer Rob Bredow Q & A Debate Siggraph Panel CG Animation Pipeline Future Squash and Stretch Splines Experiment Summary Further Reading

(c) Shane Aherne 2005

Contact:  shane@shaneaherne.com