Optical design of backlights for LCDs makes many challenging demands on the backlight designer. To meet the rapidly evolving needs of the LCD market, Computer-Aided Engineering (CAE) tools must be used to analyze and modify the design to achieve optimum performance. We describe features in the LightTools(superscript ®) illumination design and analysis software that address the requirements for modeling backlight structures and analyzing their performance via Monte Carlo ray tracing.