Animating hands are hard, and a long process with at least 30 joints to animate without motion capture can be tiresome work, and cleaning hand data can be even more challenging. I wanted to setup active hand tracking using the already setup Motion Capture stage at the Filmstorm Studio that is utilising OptiTrack hardware.
OptiTrack offer Active Tracking units which work different from standard motion capture markers that retroflect back to the cameras. Active Tracking instead uses an on-board chip, battery and up to 5 markers that report back to an Active Base Station hooked into the camera ethernet chain.
The chips are connect to tiny black IR lights which illuminate a 3D printed hollowed out markerset which helps by creating even light distribution throughout the marker.
The Prime cameras have two modes that they can track from, Passive and Active tracking. Passive tracking is for standard retroflective markers. Active tracking are for markers which are powered seperately via micro usb batteries and synced via the Active Base Station. These Active markers are great as they don't get affected back standard marker swapping which occurs as the cameras can read each marker as it's own frequency. This makes it easy to perform finger tracking as the markers don't swap between each other and maintain constant finger recognition.
For my initial prototype I built the hand gloves to be lightweight and versatile- I used boxing glove inserts, thin, bit sweat resistant and nice and stretchy for easy movement. It would be very helpful if we couldn't perform with the gloves on.
Once the markerset has been captured into Motive:Body minimal cleaning is needed to fix anything as my testing so far revealed the markers stay in good curves with no (minimal) swapping or gaps.
From Motive:Body it's as simple as exporting to your DCC which in our case is Motionbuilder using FBX Skeleton - I have a bunch of different presets made already in Motionbuilder, that handles either hands with no fingers and hands with fingers, these are pre-configured to a character in Motionbuilder that makes retargeting super simple and fast. For asset store creations the rigs for Unreal Mannequin and a Custom Unity Skeleton are setup as well, with custom root bone constraints that handle relation alignment, rotations and more. All these things are part of a workflow which makes working much faster and performing less repetitive tasks every day.
I will publish the test results in an upcoming post and members will be able to download the test animations from the Asset Area.