The controls permit the total space to be adjusted, the position of the lens within this region, and the len's focal length. The other optical elements, the space and the lens, are primitive components of the slider. Technically, given the slider element these other elements are redundant since a slider element with an infinite focal length could replace a space, and slider with zero total space could replace a lens. They are included convenience and ease of manipulation. Adjusting a component.
Every component offers three different adjustment mechanisms.
Lenses and spaces require only one parameter to be specified. Some components, like the slider and the input beam specifier , have multiple adjustable parameters. In particular, this is how one adjusts the wavelength on the input beam specifier, and how one adjusts the total width of the slider. One can directly enter the parameter value in the number field provided. Beneath this parameter field is a row of four buttons.