1. A method comprising: constructing a bounding box containing a three-dimensional (3-D) object in a 3-D coordinate system, the bounding box having at least a bounding plane; projecting a ray from a grid point on the bounding plane to the object with a pre-defined direction, the ray intersecting a surface of the object at an intersection point; and computing a parameterization value of the intersection point associated with the grid point, the parameterization value corresponding to a distance from the grid point to the intersection point.