Hi @tungtwister, thanks for your query. Head tracking is one of several streams available via the Tobii Core SDK. I assume you are using the Interaction API?
That being the case, we have available a substantial number of sample programs included that demonstrate capturing the data received from the eye tracker, including head position information. You can download the samples freely @ https://github.com/Tobii/CoreSDK
And within the samples folder, you will find the ‘streams’ applications that should hopefully give you exactly what you need to get up and running. Please kindly try this out and don’t hesitate to let us know if you require any further assistance. Thanks.