3D visualization and interactive image manipulation for surgical planning in robot-assisted surgery.Robot-assisted surgery, or "robotic" surgery, has been developed to address the difficulties with the traditional laparoscopic surgery.The da Vinci (Intuitive Surgical, CA and USA) is one of the FDA-approved surgical robotic system which is widely used in the case of abdominal surgeries like hysterectomy and cholecystectomy.The technology includes a system of master and slave tele-manipulators that enhances manipulation precision.However, inadequate guidelines and lack of a human-machine interface system for planning the ports on the abdomen surface are some of the main issues with robotic surgery.Unreachable target and mid-surgery collisions between robotic arms are the major problems that surgeons complain about in robotic surgery.The objective of this research is to design a new decision-support tool for planning port placement in robotic surgery.The decision-support system will be able to determine the optimal location of the entrance ports on the abdomen surface that is specific to the patient.