Hi @hydrlysis, glad to hear this is what you are looking for! As you may have read on the Tobii Stream Engine API landing page, there is little documentation or support provided for this advanced SDK. However, if you are looking for a more generic guide with regard to co-ordinates systems and eye tracking concepts in general, then you may find the documentation from the other SDK’s we offer of use.
For simple information using the Core SDK @ https://tobii.github.io/CoreSDK/articles/intro.html
and for more detailed information, you can view the Tobii Pro SDK documentation @
http://developer.tobiipro.com/commonconcepts/gaze.html
http://developer.tobiipro.com/commonconcepts/coordinatesystems.html
Please do let us know if we can provide you any further information. Best Wishes.