003 - Capturing Motion

As I suspected would happen, a significant amount of time has passed since my last update. This however doesn't mean that the project has not progressed. Quite the opposite! Things have moved on, grown, evolved and come-into-being etc. So let's not dwell on my time absent from this blog and let's focus on the task at hand and (more importantly) what has been happening in the last month or two.

Today was 'motion capture' day. I got covered in 35 white reflective balls (markers) and acted out a segment of the short film. 16 motion-sensing cameras recorded my movements, calculating them on-screen into a 3D representation of my body. We used the Qualisys Motion Capture System, a very sophisticated piece of kit used mostly for medical applications at the University. The system costs around £100,000.

Three of us were using this kit today. Myself and colleagues Kevin Smith and Sarah Martin took turns operating the software and performing the motion capture. Lecturer Stevie Anderson was also there to lend us a hand. The lab itself belongs to a lecturer named Danny. He was a great help to us today and walked us through the calibration and setup processes.

I wanted to perform my character's interpretive dance piece. I have always had an interest in dance and in my spare time I do Ballet and Street Dance classes. I thought I'd be able to use some of those skills for the short film. Part of me also really wanted to generally experience being the subject for motion capture.

One draw-back that concerned me about today was the fact that we were limited to a height restriction in the space. I couldn't raise my hands above my head or jump whilst performing. I felt very limited in my range of movement which isn't ideal for an expressive piece of dance. This was due to where the cameras were positioned. I feel this could have been rectified by moving most of the cameras further away to the sides of the room but Danny seemed reluctant to stray from their current setup (perhaps due to the fact that the current setup is designed for foot movement, an area this department focuses on). However we made the best of what we had.

So all the movement data has been captured but the files are still not ready for use with character animation. The data we sampled (in .qtm format)  is still not 'clean' as some of the marker positions have broken off from their assigned body part names. Tomorrow I'll go through all the files and reassign any broken positions and hopefully have a data-set that is ready for conversion to C3D, a format compatible with Autodesk Motion Builder.

Even then the work is not complete as I still have to attach the motion data to the actual character via a CAT (Character Animation Toolkit) Rig. So much to do!