The questionnaire contained 22 questions including 20 limited response choice questions and 2 space limited free-text questions. These questions cover the management of the device (questions Q1–Q4), the user’s opinion of the device (questions Q5–Q9), the application utilities (questions Q10–Q17) and the tool assessment (questions Q18–Q20). The questionnaire ended with two open questions comparing 2D and 3D view modes (questions Q21–Q22).