When working with a sequential optical system, we usually work in local coordinates, in which one surface is located a "thickness" in z away from the previous surface. Coordinate break surfaces provide decentrations in x and y, as well as tilts in x, y and z. A set of Tools under the Coordinates menu provide easy access to tools intended to simplify common tasks like adding or removing fold mirrors, or tilting/decentering components and groups of components:



Sometimes, it is more convenient to work in a global coordinate system. A common example is when an optical system has been transferred to a Finite Element Analysis (FEA) package to undertake vibration analysis. This is routinely performed with optical designs ranging from consumer electronics like digital cameras, to space-borne telescopes and satellite imaging lenses. Ultimately, a set of vibration-induced perturbations is produced, and these must be imported into ZEMAX to evaluate the optical impact of the mechanical shifts.

In this case, it is convenient to shift between local and global coordinates in either direction easily and quickly. This article describes how the Global/Local and Local/Global tools in the above menu work.