Assuming that I capture fixations, would I be able to reconstruct a heat map out of these data and if yes, how?
Yes, I see no reason this wouldn’t be possible. As for implementing this, I would take a look at the source code for other projects such as heatmap.js.
To my understanding, one needs to attach the GazeAware script in every single game object, in order to make sure that this object is being looked at. Instead, I was wondering if the following approach is better: retrieve the screen space position of the gazing point and raycast from the camera forward. If I have misinterpreted the way this works, please correct me.
Yes, you could do like this. However, GazeAware uses interactors under the hood that has other advantages. You can read more about interactors here: http://developer.tobii.com/an-introduction-to-the-tobii-eyex-sdk/
What if I want to create a screen region on the UI part (I am not using the Legacy GUI), in order to exclude data from being registered within that region? Is it possible to actually draw and visualize such a region in the editor?
Yes, if you use interactors as mentioned before, you could put an occluder around the area that should exclude data from being registered within that region. See the GazeAware3DScene example in the UnitySDK for more information.
Does this development kit work with Tobii T120? Does the computer have to have Windows 7+?
The EyeX SDK is not officially supported on the Tobii T120 so I would have to say no.
If I attach FixationDataComponent and GazeAware scripts on one GameObject, will I be able to retrieve the data, even if this game object is not viewed by the camera?
Yes. This is correct.
Should I, in every data capturing script, use the IsUserPresent() line? The user is not going to be given a chin rest – how clean data will I receive?
You should not have to check
IsUserPresent(). All data has some kind of
Invalid state. It’s also not sure that the data you receive will be “clean” just because the user is present since you can receive user presence even if you don’t receive gaze.