This paper presents a novel method for assisting surgeons in automatically computing an optimal surgical plan by directly specifying the desired correction to a facial outline. First

the desired facial appearance is designed using a 3D sculpturing tool

while the cut regions of the skull are defined based on facial anatomy. Then

the deformation of the face meshes is performed using an improved biomechanical model in which virtual external forces are driven by the displacements corresponding to the differences of node coordinates between the original and specified face meshes

and free nodes and fixed nodes are defined in terms of the contact surfaces between the soft tissues and the bones within the cut regions. Finally

the shape of the contact surfaces is updated following the deformation of the soft tissues. After registering the deformable contact surfaces and the cut surfaces

the final positions of the cut bones are estimated. Evaluation of preliminary experimental results quantitatively shows the effectiveness of the proposed approach.