Genioplasty;Does a chin forward movement create a visually longer chin even though the actual chin length is the same as before?

For a recession chin, does a chin forward movement create a visually longer chin even though the actual chin length is the same as before ? If that is true, will it be necessary to design an angled cut in the operation to make the chin actually shorter but visually the same as before ? If that is the case, is there a correlation or calculation between the forward movement and the cut angle ? Thank you so much, Doctors.