Variable Eye Position Data along z-axis

[Prachi]

I am using the Tobii Eye Tracker 4C. I have obtained the following readings:

timestamp_eye hasLeftEye eye_left_z hasRightEye eye_right_z
71233114.3 FALSE 0 FALSE 0
71233178.5 TRUE 7.560640324 TRUE 455.8907307
71233187.37 TRUE 453.4397346 TRUE 457.2775471
71233198.16 TRUE 454.3499146 TRUE 7.560640324
71233211.46 TRUE 7.560640324 TRUE 458.3187457
So here, the values of distance between the point (0,0,0) on the screen and the left and the right eyes along the z-axis comes out to be drastically different (the difference is about 45 cm though it should have been the same) from each other even though I was facing the screen and sitting straight. Sp, Is there something wrong with the values calculated or my interpretation of Z-axis and the point (0,0,0) of the co-ordinate axis is wrong?
Also, can you tell the difference between the EngineTimestamp and the Timestamp obtained through EyePositionData object?

[Grant [Tobii]]

Hi @prachi, could you kindly clarify exactly what SDK you are using please? Generally with the Tobii Tech range of SDK’s we do not expose individual eye positions, so perhaps this variable you have called is not correct.

We would recommend you use the Tobii Interaction Library @ https://developer.tobii.com/consumer-eye-trackers-interaction-library/ as the Core SDK will be discontinued in the future.

[Prachi]

Hi
I am using the Core SDK. And to obtain the above data, I have used the EyePositionStream. The following piece of code would help clarify the air better:
.
.
.
var eyePoseStream = host.Streams.CreateEyePositionStream();
eyePoseStream.Next += (o,eyeData) => {
Console.WriteLine(“{0} {1} {2} {3} {4}”, eyeData.Data.EngineTimestamp, eyeData.Data.HasLeftEyePosition, eyeData.Data.LeftEye.Z, eyeData.Data.HasRightEyePosition, eyeData.Data.LeftEye.Z);
};
.
.
.

Can you please confirm when will the Core SDK be discontinued (just a tentative timeline)?

[Grant [Tobii]]

HI @prachi, I am afraid we have been unable to reproduce this issue in house, but as the development team can no longer prioritise potential issues with the Core SDK, I would suggest you try to perform this project in the interaction library and let us know if the issue persists. Thank you.

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