A system for determining a feedback on a three-dimensional location of a pointer in a three-dimensional region of image data, the system comprising: - a display unit for computing a view of the three-dimensional region for displaying on a display; - a pointer unit for computing a two-dimensional location of the pointer on the view of the three-dimensional region, based on a pointer location input; - a location unit for computing a three-dimensional location in the three- dimensional region, based on and corresponding to a two-dimensional location on the view of the three-dimensional region; characterised by - a shadow unit for (i) determining a set of two-dimensional candidate locations for displaying a shadow on the view of the three-dimensional region, wherein the set of two- dimensional candidate locations is based on and comprises the two-dimensional location of the pointer, (ii) obtaining, from the location unit, a set of three-dimensional candidate locations based on the set of two-dimensional candidate locations, including a three-dimensional location of the pointer (iii) determining, based on a connectivity definition, a connected set of three-dimensional candidate locations comprising the three-dimensional location of the pointer, (iv) establishing a corresponding set of two-dimensional locations, comprising two-dimensional candidate locations corresponding to the connected set of three- dimensional candidate, wherein the display unit is further arranged for displaying the shadow on the view of the three-dimensional region based on the corresponding set of two-dimensional locations, for providing the feedback on the three-dimensional location of the pointer in the three-dimensional region of the image data. - a display unit for computing a view of the three-dimensional region for displaying on a display; - a pointer unit for computing a two-dimensional location of the pointer on the view of the three-dimensional region, based on a pointer location input; - a location unit for computing a three-dimensional location in the three- dimensional region, based on and corresponding to a two-dimensional location on the view of the three-dimensional region; characterised by - a shadow unit for (i) determining a set of two-dimensional candidate locations for displaying a shadow on the view of the three-dimensional region, wherein the set of two- dimensional candidate locations is based on and comprises the two-dimensional location of the pointer, (ii) obtaining, from the location unit, a set of three-dimensional candidate locations based on the set of two-dimensional candidate locations, including a three-dimensional location of the pointer (iii) determining, based on a connectivity definition, a connected set of three-dimensional candidate locations comprising the three-dimensional location of the pointer, (iv) establishing a corresponding set of two-dimensional locations, comprising two-dimensional candidate locations corresponding to the connected set of three- dimensional candidate, wherein the display unit is further arranged for displaying the shadow on the view of the three-dimensional region based on the corresponding set of two-dimensional locations, for providing the feedback on the three-dimensional location of the pointer in the three-dimensional region of the image data. (i) determining a set of two-dimensional candidate locations for displaying a shadow on the view of the three-dimensional region, wherein the set of two- dimensional candidate locations is based on and comprises the two-dimensional location of the pointer, (ii) obtaining, from the location unit, a set of three-dimensional candidate locations based on the set of two-dimensional candidate locations, including a three-dimensional location of the pointer (iii) determining, based on a connectivity definition, a connected set of three-dimensional candidate locations comprising the three-dimensional location of the pointer, (iv) establishing a corresponding set of two-dimensional locations, comprising two-dimensional candidate locations corresponding to the connected set of three- dimensional candidate, wherein the display unit is further arranged for displaying the shadow on the view of the three-dimensional region based on the corresponding set of two-dimensional locations, for providing the feedback on the three-dimensional location of the pointer in the three-dimensional region of the image data.