Global Definitions
Load the global parameters for the Double Gauss lens from a text file. The detailed lens prescription will be added when the geometry sequence is inserted.
1
In the Home toolbar, Click Parameters and select Parameters 1. Alternatively, click the Parameters 1  node in the Model Builder window.
Note: On Linux and Mac, the Home toolbar refers to the specific set of controls near the top of the Desktop.
2
In the Parameters 1  settings window, type Parameters 1: Lens Prescription in the Label text field. The lens prescription will be added when the geometry sequence is inserted.
3
In the Home toolbar, Click Parameters and choose Parameters under the Add submenu. This will add a second node where parameters may be entered.
4
In the Parameters 2  settings window, type Parameters 2: General in the Label text field.
5
Click Load from File , which is in the Parameters section below the table.
6
Browse to the model’s Application Libraries folder and double-click the file double_gauss_lens_parameters.txt. The location of the files used in this exercise varies based on your installation. For example, if the installation is on your hard drive, the file path might be similar to C:\Program Files\COMSOL\COMSOL64\Multiphysics\applications\. Then the folder for this example is Ray_Optics_Module\Lenses_Cameras_and_Telescopes.
The parameter list should look like the following:
The expressions in red indicate that there are missing parameters and hence the expression cannot yet be evaluated. These missing parameters are mostly geometry dimensions, which will be automatically added to the Parameters 1: Lens Prescription  node when the geometry sequence is inserted in the following steps.