On being Motion Captured

Among all the experiences during the internship at Gibson / Martelli Studio, the most relevant so far was being motion captured. Before going to the phenomenological aspect as a mover, it feels right to give a very brief technical explanation.

What is motion capture and how does it work?

There are different methods to capture motion, the one I am referring to is optical motion tracking with reflective markers. A set of cameras are placed at different angles around the tracking area, all looking towards the centre. The number of cameras is variable and it determines how clean the tracks will be – the more, the better. The mover(s) to be motion captured, will be wearing a set of markers on specific points of the body – mainly articulations, end of limbs and centre of long bones. Simultaneously, all the cameras will send infrared signals that will bounce on markers and come back, revealing to the cameras where all the markers are at that specific instant. This operation, repeated several times per second, gives a fairly precise digital version of the actual movement. A big role is played also by the software that measures the proportions of the real mover, creates a virtual version of it, collects motion data in real time and transforms them in a moving avatar. Amazing, isn’t it?

Now back to the experience, how does it feel to be motion captured?

Initially, I have to confess I was a bit worried that my usual motion range would be reduced due to the suit/markers or just my mind state. Actually, suit and markers were very light and accommodating and the idea that instead of a video, the outcome would be a bunch of 3D green bones, spiced up my curiosity and determination to be really creative with the movement. An interesting bias was the placement of cameras. I was very aware that all of them were pointing at the centre and that beyond the marking space, the signal would be lost and the capturing corrupted. This influenced the spatiality of my improvisation that spiralled towards the centre almost all the time. I needed to make a conscious choice to convince myself to fully cross the space, embracing the risk to exit the capturing area from time to time. It required several attempts to feel okay. Another interesting aspect of motion capture is that there is no determined front like in traditional theatre performances, but rather a circular arena, not far from b-boying circles. If each different front offers new prompts for movement generation, their combination does not help with the spiralling mentioned above – not surprisingly b-boys do amazing tricks on the spot, but rarely cross the space. Before being motion captured, I learned how to clean motion capture tracks and how long does it take to reconstruct the movement of markers gone missing. Of course, rolling on the floor is one of the major causes of obstructed markers and for this reason I agreed with myself I would not go on to that way. The other reason is the 3D spherical shape of the markers which, I was worried, would be disruptive for the rolling itself. However, towards the end of the capturing session, I realised that an empirical experience was required to confirm my assumption and, with my great surprise, the rolling felt very safe and comfortable and also the tracks did not require all the cleaning I feared. The fact the I moved really slowly was determining, but definitely left room for improvement.

In conclusion, the experience of being motion captured exceeded my expectation as well as debunked most of my preconceptions. It turned to be a really fun and liberating activity and it reconnected me with a kinesthetic memory I thought I had lost many years ago. Looking back at the captured tracks, I very much enjoyed the green avatar reproducing my moves and I could easily associate them with my original ones. I actually liked it far more than looking back at videos of me dancing and it made me reflect:

How much the way we judge our physical aspects influences the way we judge our own dancing?

How many filters need to be eliminated before we are able to appreciate a pure form of movement? And is that necessary at all?

How much of the human sensations I was exploring during my motion capture sessions comes across through a combination of moving green lines and orange dots (such as the default avatar)?

Probably, more than what I expected…

Photo credit Gibson / Martelli studio