Creative Chronicles: Motion Capture
24 August 2018
Creative Chronicles brings together key insights, information and statistics from the experts at Creative Assembly. We hope this will inspire students and those considering a career in game development.
This edition of Creative Chronicles focuses on Motion Capture.
Motion capture, or Mo-cap, has the ability to add realism of movement to your game characters, picking up detailed nuances that wouldn’t otherwise be possible in the animation process.
THE UK’S MOST PROMISING DIGITAL SKILL
There is no direct career path into motion capture, but it is intrinsically linked to animation in game development. In fact, careers in animation are increasingly looking for understanding or experience of the motion capture process.
A recent study identified animation as the most promising digital skill for the future UK workforce. Between 2004 and 2012 the UK saw a 53% increase in the number of animation professionals, with over 4,600 people currently working in animation.
HOW DOES MOTION CAPTURE WORK?
Mo-cap is the process of capturing real movement and mapping it on to a 3D model. It originates from the animation technique rotoscoping, which was first developed in 1915.
The process referred to here is one type of motion capture; Optical-Passive technology. This is the most accurate and common form of mo-cap. Reflective markers are placed around the body, especially in areas of mobility such as the joints. These markers are attached to a special motion capture suit which is worn by the actor.
Infrared lights from cameras placed around the environment reflect off the markers on the body. As the actor moves the infrared lights send data back to the computer via specialised cameras, calculating where these joints are in space. The specialist team interpret this by linking the data together, as a 3D model of the actor.
Then it's a case of building the character over the top of this skeleton or layering in an existing character model – such as an Orc from Total War: WARHAMMER. This has huge application in the games industry, both in-game and in cinematics such as marketing materials.
Mo-cap gives immediate and real time results, reducing the overall cost of key frame-based animation. This real time benefit allows trialing different styles, different movements, different weighted objects or props. The amount of animation data that can be produced within a given time is very large when compared to traditional animation techniques – reducing both cost and meeting production deadlines.
From a cinematic perspective: pre-vis, and the ability to shoot trailers in live action helps to establish camera narrative, continuity, and building the appeal of the characters performance.
A quality mo-cap result for your animators relies a lot on the direction of the shoot. You need to get the right actor to put on a good performance, and this may well be one of your enthusiastic animators with no previous acting experience.
An animator may also be directing the shoot and they need to go in knowing what they want out of it, how they want the actor to behave and the specific motions that are required.
This director has a crucial role in understanding, relaying and getting everyone on set to work to the overall vision – all within resource and budget.
Working out scales, scene compositions and prop interactions are all part of the preparation process to ensure the performance matches the artistic requirements. The director must know the story and history of the main characters’ goals and motives to ensure the character personality and appeal are accurate. This is especially important when the character is historical or comes with a complex lore that fans know before seeing it in-game or watching the cut-scene, trailer or movie.
Mo-cap is only as good as the performance, it needs to be convincing and appealing on the character in-game. But it also needs to be logical and fit with the timeline, the era, the lore and the wider context of the game. To create this emotive and immersive performance, often multiple takes are required to get the complex character interactions right – with speed of motion and strength of motion consistent across all these shots to avoid continuity errors.