A computer-implemented medical visualization method, comprising: identifying a three-dimensional model (112; 206) of an anatomical item of a particular mammal, the anatomical item comprising an interior open space; automatically identifying, with a computer-implemented visualization system (100; 200; 600) and according to identified boundaries of the interior open space, a path through the interior open space of the anatomical item; identifying a smooth curve defined by a plurality of points along the path; for each particular point (506A, 506B) of the plurality of points (506A, 506B) of the smooth curve, automatically performing operations comprising: generating a plurality of rays around the particular point in a common plane (508A, 508B) perpendicular to a tangent of the smooth curve at the particular point (506A, 506B); and determining lengths of each of the plurality of rays from the particular point (506A, 506B) to the boundaries; centering the smooth curve in the interior open space by repositioning the plurality of points that define the smooth curve at positions that are indicated by the lengths of the plurality of rays as being centred in the interior open space; and displaying the three-dimensional model of the anatomical item superimposed with the smooth curve to a user with the computer-implemented visualization system (100; 200; 600); characterized in that the method further comprises a step of displaying a visual representation of an item configured to be moved along the smooth curve superimposed with the anatomical item and the smooth curve to the user with the computer-implemented visualization system (100; 200; 600), wherein the item represents a three-dimensional medical device. identifying a three-dimensional model (112; 206) of an anatomical item of a particular mammal, the anatomical item comprising an interior open space; automatically identifying, with a computer-implemented visualization system (100; 200; 600) and according to identified boundaries of the interior open space, a path through the interior open space of the anatomical item; identifying a smooth curve defined by a plurality of points along the path; for each particular point (506A, 506B) of the plurality of points (506A, 506B) of the smooth curve, automatically performing operations comprising: generating a plurality of rays around the particular point in a common plane (508A, 508B) perpendicular to a tangent of the smooth curve at the particular point (506A, 506B); and determining lengths of each of the plurality of rays from the particular point (506A, 506B) to the boundaries; centering the smooth curve in the interior open space by repositioning the plurality of points that define the smooth curve at positions that are indicated by the lengths of the plurality of rays as being centred in the interior open space; and displaying the three-dimensional model of the anatomical item superimposed with the smooth curve to a user with the computer-implemented visualization system (100; 200; 600); characterized in that the method further comprises a step of displaying a visual representation of an item configured to be moved along the smooth curve superimposed with the anatomical item and the smooth curve to the user with the computer-implemented visualization system (100; 200; 600), wherein the item represents a three-dimensional medical device. generating a plurality of rays around the particular point in a common plane (508A, 508B) perpendicular to a tangent of the smooth curve at the particular point (506A, 506B); and determining lengths of each of the plurality of rays from the particular point (506A, 506B) to the boundaries; centering the smooth curve in the interior open space by repositioning the plurality of points that define the smooth curve at positions that are indicated by the lengths of the plurality of rays as being centred in the interior open space; and displaying the three-dimensional model of the anatomical item superimposed with the smooth curve to a user with the computer-implemented visualization system (100; 200; 600); characterized in that the method further comprises a step of displaying a visual representation of an item configured to be moved along the smooth curve superimposed with the anatomical item and the smooth curve to the user with the computer-implemented visualization system (100; 200; 600), wherein the item represents a three-dimensional medical device.