We will now model the reflected path using multiple configurations.

Open the Multi-Configuration Editor (Editors > Multi-Configuration) and insert a configuration (Ctrl+Shift+Ins)

Insert a PRAM operand in the Multi-Configuration Editor and specify the X tilt parameter (Param #3) of coordinate break surface #5.



Place a pick-up solve on the second configuration of -1 factor.





We need to change the material type of surface 4 from N-BK7 to Mirror. Insert a GLSS operand for surface 4 and specify Mirror for configuration 2.

Switch Lens Data Editor to configuration 2 (Ctr-A). The Lens Data Editor should display “Config 2/2” in the title bar.

Enter the following settings for the 3D layout to display all configurations.

Update the layout

Notice how the reflected rays (in green) propagate in the wrong direction (upward). This is due to improper thickness sign convention after the mirror in configuration 2, causing "virtual" ray propagation. Thicknesses corresponding to real propagation (see section “Real propagation” in chapter 3 of the manual) always change sign after a mirror. After an even number of mirrors (including zero mirrors), thickness are positive for real propagations and negative for virtual propagations (see section “Virtual propagation” in chapter 3 of the manual). After an odd number of mirrors, thicknesses are negative for real propagations and positive for virtual propagations. This sign convention is independent of the number of mirrors, or the presence of coordinate breaks. This fundamental convention cannot be circumvented through the use of coordinate rotations of 180 degrees. Therefore, we need to change the thicknesses of surface 5 and 6 to -20 mm in configuration 2.

Insert THIC operand for surfaces 5 and 6 and place -1 pick-up solves for the second configuration.

Update the 3D layout