A system for generating a patient specific instrument for use as a surgical guide for installing a selected implant, the system comprising: a processor; and a computer readable medium storing machine readable instructions comprising: a region modeling component configured to provide a three-dimensional model of a region of interest within a body from at least one imaging scan of the region of interest; a surgical planning component configured to display a model of the selected implant and the three-dimensional model of the region of interest to a first user and allow the first user to position the model of the selected implant within the three-dimensional model of the region of interest, the model of the selected implant having at least one hidden attribute, wherein a hidden attribute is a portion of the model of the selected implant that does not directly correspond to a portion of the selected implant and is not visible to the first user; and a PSI design component configured to provide a patient specific instrument model from a generic PSI model according to the position of the model of the selected implant within the three-dimensional model of the region of interest and the at least one hidden attribute, wherein the at least one hidden attribute comprises an extension of the model of the selected implant representing at least one guide structure in the patient specific instrument model for maintaining one of the selected implant and an instrument associated with the selected implant in a desired orientation relative to the region of interest. a processor; and a computer readable medium storing machine readable instructions comprising: a region modeling component configured to provide a three-dimensional model of a region of interest within a body from at least one imaging scan of the region of interest; a surgical planning component configured to display a model of the selected implant and the three-dimensional model of the region of interest to a first user and allow the first user to position the model of the selected implant within the three-dimensional model of the region of interest, the model of the selected implant having at least one hidden attribute, wherein a hidden attribute is a portion of the model of the selected implant that does not directly correspond to a portion of the selected implant and is not visible to the first user; and a PSI design component configured to provide a patient specific instrument model from a generic PSI model according to the position of the model of the selected implant within the three-dimensional model of the region of interest and the at least one hidden attribute, wherein the at least one hidden attribute comprises an extension of the model of the selected implant representing at least one guide structure in the patient specific instrument model for maintaining one of the selected implant and an instrument associated with the selected implant in a desired orientation relative to the region of interest. a region modeling component configured to provide a three-dimensional model of a region of interest within a body from at least one imaging scan of the region of interest; a surgical planning component configured to display a model of the selected implant and the three-dimensional model of the region of interest to a first user and allow the first user to position the model of the selected implant within the three-dimensional model of the region of interest, the model of the selected implant having at least one hidden attribute, wherein a hidden attribute is a portion of the model of the selected implant that does not directly correspond to a portion of the selected implant and is not visible to the first user; and a PSI design component configured to provide a patient specific instrument model from a generic PSI model according to the position of the model of the selected implant within the three-dimensional model of the region of interest and the at least one hidden attribute, wherein the at least one hidden attribute comprises an extension of the model of the selected implant representing at least one guide structure in the patient specific instrument model for maintaining one of the selected implant and an instrument associated with the selected implant in a desired orientation relative to the region of interest.