This step is often overlooked. It is important to test that the tolerances have been set up correctly. To do this, we will build some Monte-Carlo files and examine what it is doing.

Click on Tools...Tolerancing...Tolerancing to open the Tolerancing dialog box. Click the 'Reset' button to restore the default settings of this dialog, and then set it as follows (only changed settings are highlighted:






This means that ZEMAX will only build Monte-Carlo files. The files will have the name test prepended to MC_Txxxx, where xxxx is the file number. If you run the tolerancer open one of the M-C files, you will see something similar (actual numbers will vary as they are random) to this:



See what ZEMAX has done. Element tolerances (TE** operands) have been converted to coordinate breaks to implement element tilts and decenters. The (previously) STANDARD surface types have been converted  to IRREGULAR surface types so that surface tilts and irregularity can be accounted for. Various lens data (like thicknesses, radii, glass type etc.) have been perturbed from their nominal value. Note that the thickness of the interlens separation has become a variable, and that a merit function has been defined:



The Monte Carlo files should be carefully inspected at this stage so that you are sure you understand and agree with all the changes that have been made.