1. A method for providing a visual cue for placing a first geometric entity in a three-dimensional space represented in a computer-implemented graphics program, comprising: (a) displaying a two-dimensional viewport of the three-dimensional space on a display device attached to a computer; (b) selecting a first point in the two-dimensional viewport; (c) based on the first point, displaying a visual cue in the two-dimensional viewport that indicates a coordinate system plane within the three-dimensional space, wherein the coordinate system plane identifies a plane where the first geometric entity is to be placed; (d) using the visual cue, selecting a second point on the coordinate system plane in the two-dimensional viewport; and (e) placing the first geometric entity on the coordinate system plane based on the second point.