Gaze Point data values from Tobii Pro SDK (Matlab)

[Roberto Manduchi]

According to the SDK documentation, “The coordinates for the gaze point are given as a 3D point in the User Coordinate System”. However, if I look at the data (GazePoint.InUserCoordinateSystem), the third (z) coordinate is always constant (e.g. 9.10 mm). This looks odd for two reasons:
– The front face of the tracker (placed at the bottom of the screen) makes an angle with respect to the screen, hence the gaze points on the screen cannot have constant z
– Even if the tracker were parallel to the screen, I would expect to read a negative value for z (the Z axis of the tracker points away from the screen, and the tracker is placed in front of the screen)

So my question is: What exactly do the 3D gaze point in the User Coordinate System represent (since they apparently do not represent the location of a point on the screen)?

Thanks!

[I am using the Matlab version of the Tobii Pro SDK on a MacBook Pro. The tracker (Tobii Nano) was calibrated successfully.]

[Grant [Tobii]]

Hi @manduchi and thanks for your query. The Tobii Pro SDK is part of the Tobii Pro business department.

This forum is intended for support with the Tobii Tech Consumer-level eye trackers (ET5, 4C, etc) and their associated SDK’s.

Please get in touch with Tobii Pro Support team directly @ http://www.tobiipro.com/contact/contact-support/ for an
answer to your query.

Apologies for the inconvenience and thanks for your understanding. Best Wishes.

[Author]

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