The online Knowledge Base resource was created by Zemax Development Corp. to help customers optimize their use of the Zemax optical system design software. The Web site provides application notes, a section of frequently asked questions and tutorials in such areas as stray light, fiber coupling, and sequential and nonsequential ray tracing. Besides sections on program basics and installation and troubleshooting, the portal offers articles on classical lens design, laser beam propagation, creating complex 3-D geometries, how to model LEDs and other complex sources, and how to select a computer to run with the program. A collection of customer-written articles is included.