Simulator operation technique. (A) To operate the simulator, the participant places a reproduction of an ultrasound probe on a mannequin’s chest. (B) User interface. (C) Enlargement of three-dimensional visual guidance indicator. The position and orientation of the acquired image (blue) and anatomically correct image (green) are displayed with the angle error (white arc). (D) Enlargement of numeric report of skill metrics. The angle error is above and the probe placement error is below.