Posted by: Leslie White | March 6, 2011

Motion Capture

This past Friday, I had my first experience using  Motion Capture technology – something I have wanted to do since I saw a behind-the-scenes feature on how Gollum (from Lord of the Rings) was animated.

My model in the MoCap suit.

I used the Vicom “MoCap” system at the UIC Bat Cave (everything relating to motion capture technology has a fantastic name :p) to capture a walk and run cycle. Before the actual motion capture can begin, the stage and all 8 cameras must be calibrated. The human model must wear a close-fitting suit covered in strategically placed infrared markers. He/she must also perform a Range of Motion (ROM) to process the marker calibration. This setup process can take up to 1 hour.

Each complete movement must start and end in the “T-pose”, which is demonstrated in this post’s photograph. The MoCap system does have its limitations, however. Some positions, such as crouching down, block some of the markers so that they are not picked up by the cameras. When markers are occluded like this, the computer essentially looses communication with those markers and cannot record the movement of the the occluded marker(s). For motions such as walk cycles, however, none of the markers are lost, and the system can pick up very finite movements that would take hours to reproduce in keyframe animation.

Now that I have captured the motions I need, there is a still post-processing work to be done. I will be using Motion Builder to link up the MoCap movement with the skeleton from my research project. Soon enough, I will have my 9,500 year old skeleton walking around again!

Special thanks to Hiromi for assisting me with this process, and to my model David for coming all the way down to the city and for wearing the funny little MoCap hat!

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Responses

  1. Hey there!
    This brings me back to my first mocap shoot 14 years ago. You never forget your first time in the suit. 🙂
    Optical systems are cool but if you want to capture those crouches, check-out the revolutionary system from Xsens! http://www.xsens.com
    No cameras, no occlusion and the resuts speak for themselves with clients like ILM, Sony, EA, Lockheed Martin, 20th Century Fox, Universal and many more… we’ve captured skydivers, snowboarders and I’ve actually been underwater in the suit! Cool tech.
    Check it out!
    Dan


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