Hello,
I can not find documentation for pi studio. Link "User Guide" from site
http://docs.ipisoft.com/iPi_Mocap_Studio shows nothing.

Hello
Thank you for pointing out on meaningless links. We'll correct them.

Actually, our documentation is more task- than product-oriented. So please start your exploring from the main page depending on your task.
There are comprehensive user guides for specific camera configurations: multiple color cameras, single or multiple depth sensors.
Also, there are shorter articles on specific topics like distributed recording, using motion controllers and so on.