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 # Example 11: Basic Sequential

 Last update: 09.03.2026 

Ex 11: A new sequential file is created and saved. The system aperture value (entrance pupil diameter) and apodization type are changed. Thickness, radii, and material are changed and a rectangular aperture is placed on surface 1. The Scale Lens tool is used to change the system units to inches. A quick focus is performed and then a universal plot is created. The settings for the universal plot are changed to display the RMS spot size as a function of the thickness on the last surface.

```
Input:		None

Output:		API\e11_basic_seq.zos
            Zemax\Configs\UNI.CFG

```

[C#](example_11_cs.md)

[C++](example_11_cpp.md)

[Matlab](example_11_m.md)

[Python](example_11_py.md)