Hi @yannrl7, The old Tobii Gaze SDK is no longer available and has since been replaced with the Tobii Stream Engine API available @ http://developer.tobii.com/tobii-core-sdk/
However, at the current time neither the Interaction nor Stream Engine API supports multiple monitor setups and as such is not documented.
That being said, the previous advice holds in that the normalised gaze co-ordinates lie within the values between 0 and 1 for the active screen being used. Negative values or those greater than 1 represent captured gaze data that lies out with the active screen but still detectable by the eye tracker which could theoretically be used by your program to map onto another adjacent screen, but I am afraid this is something we do not support for the time being. I hope this clears up your enquiry.