Hi,
Thanks for questions. Greenlaw's comments actually contain good comments about clothing.
Our software is designed to work with clothing models that can be seen at the "Actor" tab. Clothing should be solid-color, and best choice is black short-sleeve T-shirt over bright (red or green) long-sleeve shirt, with blue jeans and black shoes.
Dark (ideally, black) color for torso is important because it helps to minimize the effect of shadows. Current generation of our technology is not very good at handling shadows.
It certainly helps having good contrast between hands and torso. So gloves can be a useful option for dark-skinned person. For light-skinned person, there is not much sense in wearing gloves.
Having high-contrast solid-color background like a greenscreen helps, but our software can work with cluttered background, as you can see from tutorial video.
Things like special yellow patches on knees would not really improve tracking.
An example of ideal clothing/background setup is presented in the video kindly published by our user Txesmi:
http://www.youtube.com/watch?v=G5b-NQEErfA(captured animation for the above video:
http://www.youtube.com/watch?v=rXR5tpk1SXc)
Current version of our software cannot do matchmoving so SythEyes and similar recommendations are not applicable here. Background tracking markers are not useful because the point of motion capture is capturing actor motion in 3D, while discarding original background. You can add any kind of background later when rendering motion in 3D. Binding your 3D coordinate system to real-world objects (ground plain, etc.) can be done during multi-camera calibration step, as explained in our calibration video tutorial.
As a practical advice, GAP (
http://www.gap.com/browse/category.do?cid=5225) sells inexpensive clothes ideally suited for iPi Mocap, like simple solid-color shirts and straight fit jeans.