A depiction system for generating a real time correlated depiction of movements of a surgical tool for uses in minimally invasive surgery is described. In an embodiment the system comprises computer system, 3D surface data generation means and position data generation means for obtaining real time spatial position data of at least a part of the surgical tool. At least one of said 3D surface data generation means and said position data generation means comprises surface position data generation means for providing surface position data of at least said target area. The computer system being programmed for determining a 3D surface contour of at least a part of said target area of said surface section of said minimally invasive surgery cavity using said 3D data, determining real time spatially position(s) of said surgical tool relative to at least a part of said target area of said at least one surface section using said spatial position data and said surface position data, calculating depiction data representing a depiction of said real time relative spatial position(s) of said surgical tool onto at least a portion of said surface contour of said surface section of said minimally invasive surgery cavity, and for transmitting said depiction data to said display unit for real time correlated depiction of movements of said surgical tool.
