01 March 2021
When we think of motion capture performances, what comes to mind is actors rolling around in front of a green screen, in a lycra suit, covered in small tennis balls.
Which is not wrong. But there’s more to capturing motion than just a lycra suit.
We’ve already looked at the acting skills needed for a successful mocap performance, so let’s dive deeper into the technical side of things, and better understand every piece of mocap tech needed to make a performance work.
1.The motion capture suit
What many people refer to as a “motion capture suit”, is really just a lycra outfit to hold the markers tight to the actor’s skin while they can move around without being inhibited. But the markers attached to these suits are the real star of the show.
These retro-reflective 3D tracking dots are small spheres positioned strategically on the performer to record their real-life movements. Picture the markers as computerised puppet strings – pulling the skeleton of the character through frames that then creates animated motion.
Although traditional markers need to be attached to a suit or directly to skin, our revolutionary BaSix system only uses six active marker rigs which are attached to a person’s body using gloves, footstraps, a visor, and a belt, over everyday clothes. No suit needed!
The retro-reflective markers are then tracked by motion capture cameras. The more cameras used to do the tracking, the more complete, detailed and accurate the outcome will be.
If you’re picturing a classic SLR camera that someone would use on a photoshoot, think again. Motion Analysis’s cameras, such as the Kestrel, are used to produce marker coordinate data rather than an image. They detect only infrared or near-infrared light and are able to pass information at a much higher frame rate than a typical television camera could.
The Kestrel 4200 is one of the best pieces of hardware out there when it comes to mocap tech, and is an excellent investment for large and complex mocap systems. But if you’re working on a limited budget then the Kestrel 300 will still deliver a high quality motion capture.
An animation studio, game maker or filmmaker will use professional 3D animation software – Autodesk’s Maya is one of the more popular ones – which provides all the modeling, rendering, simulation, texturing, and animation tools that need to be added once motion is captured.
Before tracking movement for animation, animators need to have a basic skeleton mapped out for the character they are creating. This skeleton will help them to determine how many markers they need to use, and what levels of movement they need to track. For example, an acrobatic dancer who is going to be doing backflips will require more markers than a rigid limbed robot who stomps around.
The cameras and markers capture the motion and the data driving the character’s skeleton-rig is sent back to the animation program where it’s transformed with fur, clothing, or skin.
Our Cortex system is capable of solving the skeletons of any structure with any number of segments, including bipeds, quadrupeds, props, facial animation and more.
Because most humanoid characters have similar skeletons and move in similar ways, it’s possible to develop marker sets which can be used on a number of skeletons.
Our Basix Go software has a built-in, constrained and tracked human skeleton at its core, which works for almost all humanoid characters. The six active markers strapped to the performer’s waist, feet, hands and head, are enough to track a human’s motion very accurately and precisely. Then within our software, (or in the receiving package), this rig can be mapped to the creator’s humanoid skeleton.
Having this built in solver-skeleton that’s ready to be tracked, means our BaSix system setup time is minimal compared to other traditional mocap systems.You simply need to walk into the studio once cameras are set up, strap on your six markers, stand in a “T” pose, press “reset skeleton” in the software, and voila – you’re tracking movement and data is being streamed live into your animation package in real-time, ready to be recorded.
Interested in finding out more about our mocap tech? Find out more about our systems and book a demo today.