Since you are talking about UCS (User Coordinate System) I’m guessing you are looking at samples in the Gaze SDK. It is possible to do what you want with the Gaze SDK, but quite cumbersome.
It would be easier to use the EyeX SDK to access these values through the EyeX Engine API:
– The 3D coordinate system of the eye position data stream is centered on the center of the screen and aligned with the screen plane (that is the screen the eye tracker has been set up on and calibrated for using the EyeX Engine).
– The screen size is available in millimeters and pixels
You would have to average the eye positions of the individual eyes to a single point, for example centered between them, and take into account that some data points in the eye position stream may only have data for one of the eyes.
The cyclope’s eye position can be used in combination with the screen size to calculate an off-axis perspective projection matrix to create the ‘window’ effect you want.