1. A method for generating a three-dimensional (3D) model of a grading transition, comprising: receiving grading transition data specifying a footprint, an initial grading distance, and an ending grading distance, wherein the footprint includes a first segment and a second segment connected at a bend point; determining a grading distance transition rate using the initial grading distance and the ending grading distance; generating daylight lines having smooth transitions above and below the bend point by sweeping a circle along the footprint, wherein the radius of the circle increases according to the grading distance transition rate, and wherein the circle is centered on the footprint; assigning elevation values to stations along the daylight lines; and storing the elevation values and the daylight lines in a memory as part of a computer aided design (CAD) drawing that models real-world objects.