What is "openni"

OpenNI or Open Natural Interaction is an industry-led non-profit organization and open source software project focused on certifying and improving interoperability of natural user interfaces and organic user interfaces for Natural Interaction (NI) devices, applications that use those devices and middleware that facilitates access and use of such devices.

PrimeSense, who was founding member of OpenNI, shutdown the original OpenNI project when it was acquired by Apple on November 24, 2013, since then Occipital and other former partners of PrimeSense are still keeping a forked version of OpenNI 2 (OpenNI version 2) active as an open source software, primary for their own Structure SDK ( Software Development Kit) which is used by their Structure Product.