A virtual point (VP) is an interface used to connect components which allows the engineer to build up, for example, a full vehicle model. The point is “virtual” because typically it cannot be measured directly. By placing sensors around the VP and by assuming the local region behaves rigidly, DIRAC transforms the measured data as if it were measured at the VP.
The Virtual Point includes both translational and rotational degrees of freedom, data which traditionally is impossible to obtain. The transformation also gives valuable insights about the quality of the measured data and the resulting FRF model. Force impacts are transformed in a similar fashion.
See the short video below, explaining how virtual points are used in practice.