The present invention is directed to a computer system and methods for designing a tunnel in accordance with tunnel design parameters. The computer system and methods load a tunnel design as a visual model of a respective tunnel on a user interface. The computer system and methods enable a user to select a point on the user interface, such that the point defines one or more objects of the visual model. The computer system and methods further enable the user, using a pointing device, to move the point toward a desired location on the user interface, such that the pointing device traverses a plurality of locations on the user interface. As the pointing device traverses each of the plurality of locations, the computer system and methods provide a real-time preview of the respective placement of the selected point and the one or more defined objects on the user interface. If the computer system or methods determine that the respective placement fails to conform to specified tunnel design parameters, the computer system and methods may: prevent the preview from updating to the respective location, automatically fix the respective placement in the preview to conform to the specific tunnel design parameters, or visually indicate in the preview the one or more defined objects that fail to conform.