After optimizing, analyzing and tolerancing a sequential optical system, it is often required to convert it to a non-sequential system, typically when needing to look at detailed, opto-mechanical stray light problems.

There is a convenient tool in sequential ZEMAX, under Tool>Miscellaneous>Convert to NSC Group, that automatically converts a range of surfaces to the equivalent non-sequential objects. This tool converts most commonly used surface types, surface apertures and coordinate breaks into non-sequential component group. However, some sequential surfaces do not have a non-sequential equivalent and cannot be converted. Also, there are configurations that cannot be converted or not yet supported.Carefully check the converted lenses when using this tool.

Once the lens has been successfully converted, it is easy to add objects modelled in CAD packages to represent mounts, baffles, iris apertures etc and look in detail at the interatction between the optical and mechanical components of the system.

The conversion tool capabilities are constantly being updated to support more surface types. For more detailed information about the currently supported surface types, please refer to chapter 8, section Miscellaneous>Convert to NSC Group, in the most current version of ZEMAX manual.

We will go though an example on how to do this conversion . We will use the Cooke Triplet sample file located in {ZEMAX root}/Samples/Sequentia/lObjectives/Cooke 40 degree field.zmx.