Two optical ray trace conventions are addressed. The choice of ray-surface intersection has been based on convention rather than examination of the situation. The problem can be handled automatically by specifying an active side to a surface and then associating a direction to the surface normal based on that active side. The two solutions obtained by solving the equation of the line and surface can then be tested by scalar product with the normal. The reflection algorithm is restructured to eliminate the need for a negative index and the concept of rays traveling in negative space.