If you’ve seen the Lord of the Rings series, Avatar, or have played videogames recently, then you have likely experienced watching some motion capture performances.
### What is MoCap?
Motion capture, or “MoCap”, is when the movements of an actor or performer are tracked by a computer program and then applied to a digital asset or rigged model. It’s a complex process and requires not only a sophisticated camera setup and robust machines, but generally also needs a team of technicians to make sure everything goes smoothly.
Once applied to a computer generated (or CG) asset, the movements of the performance are all there, cutting down animation time significantly. This also allows for certain unique actor or character performances to be captured with a bit more detail.
For example, in the movie Avengers: Age of Ultron, it’s pretty clear that you’re looking at actor James Spader when the robot Ultron is talking, especially in the party crashing scene. Spader has a particularly distinct way of moving and presenting himself, and using his mocapped performance, the animators were able to keep and accentuate that physical presence perfectly.
### How It’s Done
MoCap studios are usually big warehouse or studio-type areas, where a large empty spaces can be turned into what’s called a “volume”. The volume is surrounded by a large number of light-sensitive cameras in as many directions as possible, from top to bottom of the space and in every corner.
The performers wear special black suits which are outfitted with tiny reflective balls that are strategically placed all over the body. These are the motion trackers, which are captured by the cameras and translated into the computer software. It’s important that the volume is kept clear of objects that are reflective, which is why the performer is basically stripped down to a skintight black suit, and any person or object within the active volume needs to also be as dark as possible.
Much like a movie set, shots and multiple takes are scheduled and recorded over a period of time, and the director can even mix and match parts of takes to get the best performance possible.
Once all the data is recorded and organized, it’s cleaned up and sent to animation. Animators then can merge, alter, accentuate, and embellish the performance – adding smoothness or detail to parts of the character which can’t be captured or that don’t fit exactly into the scene for whatever reason.
Animators will also look at witness cams as they work – a witness camera is actual video of the performer on the mocap stage doing the shot and take that the animator is working with. They can use this as reference for if something seems off, or if they need more detail, say in the facial expressions of the character.
The final product is a hybrid of real life performance and animation, and can result in some of the most realistic movement in digital media if done well.
### Technology and the Future
Over the last decade, mocap technology has become more and more complex. What used to be 10 or 20 tracking points along basic joints in the body has bursted to sometimes into the thousands along multiple muscle groups – some of which are subtle, such as on the face.
As of right now, motion capture still needs the help of animators to add those final touches and flourishes to give the movements a natural feel in production, but soon computers may be able to track enough detail and reality in real time that the process will be almost instantaneous. It’s mind blowing, no?