The SPI accepts encoder and other format data from moving axes.  Using data from the high precision encoders attached directly to the moving parts of the head, lens or crane, the SPI updates precisely the exact location of every axis and communicates this in a high speed serial data stream to the VR graphics system. The powerful processing electronics at the core of the SPI ensure that data is produced accurately and fast enough to be synchronised with every frame of video, ensuring smooth movement of the real and virtual worlds. 

For PTZF systems the SPI only needs to move through the centre points of pan and tilt, and reach the end-points of zoom and focus to be completely referenced - making the process extremely quick and simple.  For systems including a VR pedestals where a reference point in 3-dimensional space is required there is a simple reference procedure using a floor tile in the corner of the studio, or by simply carrying out a 2-point triangulation procedure without any reference tile required.