A depiction system for generating a real time correlated depiction of movements of a surgical tool in a minimally invasive surgery cavity, the system comprising • a computer system (1, 11, 101, 111, 141, 151, 161) configured for being in data communication with a display unit (4, 14a, 14b, 50, 60, 103, 104, 105, 113, 133, 163), • 3D surface data generation means for providing the computer system with three-dimensional data representing at least one surface section in 3D space of the minimally invasive surgery cavity, wherein said surface section comprises a target area and wherein said 3D surface data comprises real time measured data, and • position data generation means (3, 12) for obtaining real time spatial position data of at least a part of the surgical tool (24, 107, 117, 137, 157, 167) and for transmitting said obtained spatial position data to said computer system (1, 11, 101, 111, 141, 151, 161), wherein at least one of said 3D surface data generation means (2, 12) and said position data generation means comprises surface position data generation means (3,12) for providing surface position data of at least said target area, said computer system (1, 11, 101, 111, 141, 151, 161) being programmed for • consecutively determining a 3D surface contour of at least a part of said target area of said at least one surface section of said minimally invasive surgery cavity using said 3D surface 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 (40, 41, 42, 43, 61, 71, 91, 92) of movements of said surgical tool, wherein the depiction comprises an encoded, non-image-accurate depiction of the surgical tool comprising a dynamic scaling of colours representation, wherein the dynamic scaling of colours representation comprises a visual coloured representation of the determined real time spatially position(s) of the surgical tool relative to the determined 3D surface contour, wherein the colouring is dynamically modified in correlation to changes of the spatial position and optional orientation caused by the movements of the surgical tool relative to the determined 3D surface contour. • a computer system (1, 11, 101, 111, 141, 151, 161) configured for being in data communication with a display unit (4, 14a, 14b, 50, 60, 103, 104, 105, 113, 133, 163), • 3D surface data generation means for providing the computer system with three-dimensional data representing at least one surface section in 3D space of the minimally invasive surgery cavity, wherein said surface section comprises a target area and wherein said 3D surface data comprises real time measured data, and • position data generation means (3, 12) for obtaining real time spatial position data of at least a part of the surgical tool (24, 107, 117, 137, 157, 167) and for transmitting said obtained spatial position data to said computer system (1, 11, 101, 111, 141, 151, 161), • consecutively determining a 3D surface contour of at least a part of said target area of said at least one surface section of said minimally invasive surgery cavity using said 3D surface 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 (40, 41, 42, 43, 61, 71, 91, 92) of movements of said surgical tool,