Game Development Reference
and some simple electronics it is possible to create a motion capture suit
very cheaply. Then we will look at a particular type of motion capture file,
the Biovision Hierarchy (BVH) file, which is often used as a means of
saving and exchanging motion files. We will look at creating a BVH viewer
and applying some sample BVH files to a single mesh character. Finally,
we will look at how to enhance motion capture files by using both Inverse
Kinematics and secondary animation channels. Mocap is regularly used
in games because it makes the low polygon digital actors seem very
lifelike. The techniques are quite simple and well worth studying.
The principle behind all motion capture methods is essentially the same.
An actor is placed in a suit of some description and then they perform an
action. Throughout the actors' performance, the position of their limbs is
scanned up to 50 times a second and recorded to a file. In order to assess
the effectiveness of the motion, it is often applied in real-time to a low-
resolution version of the target model using a suitable application
program. Filmbox from Kaydara is a popular tool for real-time viewing.
Figure 12.2 Filmbox being used to provide real-time feedback of a mocap session.