One variation of a method includes: accessing a virtual patient model defining a target resected contour of a hard tissue of interest； after resection of the hard tissue of interest during a surgical operation, accessing an optical scan recorded by an optical sensor facing a surgical field occupied by a patient, detecting a set of features representing the patient in the optical scan, registering the virtual patient model to the hard tissue of interest in the surgical field based on the set of features, and detecting an actual resected contour of the hard tissue of interest in the optical scan； and calculating a spatial difference between the actual resected contour of the hard tissue of interest and the target resected contour of the hard tissue of interest represented in the virtual patient model registered to the hard tissue of interest in the surgical field.
