15 March 2009

Tea Vui Huang's Mocap Phone Assist
The Animator In Producing Realistic Animation

Mocap (or motion capture) refers to the recording of human/object movements for applications such as animation, movies and games.

The recorded movement data is then used to animate human and object models in 3D animation.

Tea Vui Huang's Mocap Phone is a mobile application that enables a suitable mobile phone to be a limited 2-axis / 3-axis motion capture device.

New generation of mobile phones appearing in the shops are starting to feature motion sensors as standard features of the phone.

These Wii-mote-like motion sensors are generally utilising a MEMS (Micro-electro mechanical systems) Accelerometer.

It is this built-in Accelerometer (e.g. Analog Devices ADXL340KCPZ) that Mocap Phone uses to detect movements of the phone. A red LED strobe-ring decal is totally optional.

The Accelerometer's pitch, roll & direction is used for 3-axis motion capture. However, some phones do not have sensors for direction and hence only 2-axis motion capture of pitch & roll is available.

These information are subsequently converted into (rx, ry, rz) animation data and / or (tx, ty, tz) position data in the phone. They are then exported to the phone's removable storage (microSD card) in widely-used industry-standard mocap formats such as Vicon C3D, Autodesk FBX and Acclaim AMC & ASF, as well as a direct Maya MEL format.

If a built-in Accelerometer is available for motion capture, you can point, roll & pitch the phone to generate motion data. However, if an Accelerometer is NOT available for motion capture on the phone, you can still use keys 1/3, 4/6, 7/9 to simulate azimuth, roll & pitch.

Note: Selecting Vicon C3D format will result in 2 position data files - a pose & a motion file; Maya MEL usage - Enter the animation script name followed by the object name at the MEL command line, e.g. 'dance nurbsCube1';

You can use Autodesk FbxConverter to convert FBX animation files into 3DS & COLLADA format; Selecting Acclaim format will also result in 2 position data files - a skeleton ASF & a motion AMC file; See the following sections for more information.