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Using the sliders window

Sliders let you vary parameters like surface thickness or curvature by dragging a slider control, with any open diagnostic windows (spot diagrams, etc.) updating dynamically. To make a parameter adjustable by sliders, you need to use the Surfaces window (which can be summoned from the System menu). In the table on this window, use the pop-up button beside the parameter to set its pick-up type to "Variable". Once you have done this the parameter will appear in the sliders window.

The Sliders window (summoned from the Tools menu) looks like this:

sliders window

The Sliders window contains a table with several columns. The "variable" column gives the so-called "key path" of the variable in the lens. In the example above, we have the rx rotation of surface 1 (which is a coordinate break surface) and the thickness of surface 3. The "nominal value" column is the value originally specified for the variable in the surface editor. The "delta" column can be changed to increase or decrease the size of the change that is made when you move the slider to full scale. The "present value" column is the value of the parameter taking into account the slider position. The final column is the slider control itself. Just hold the mouse button down on the slider control and drag left or right to decrease or increase the parameter. With the slider full left the value of the parameter will be the nominal value minus delta and with the slider full right the value of the parameter will be the nominal value plus delta.

The window can be resized to expose all sliders, if you have made too many to be seen at once with the window at its default size. Also, if you make the window wider the sliders will be longer, which can be convenient.

Beneath the sliders is a Restore values to nominal button. Pressing this button sets the sliders back to their neutral position and all of the controlled parameters back to their nominal values. It is a good idea to press this button before closing the sliders window, unless you really mean to leave the parameters at the values you have selected using the sliders.

Pressing the Set values as nominal button makes the present values the nominal ones and sets the sliders back to their neutral position. This is useful when you want to slide further than you can, but you do not want to change the delta parameter.

The Include focus checkbox will add the thickness of the focus surface in the list of variables, if it is not already.

At the bottom of the sliders window are buttons to enable and disable "slider-friendly" plotting. Pressing the Enable button requests any open diagnostic windows to enter a mode where their plotting scale only expands. Once you have done this the scales will expand to accomodate the largest range of data encountered. In a spot diagram, for example, the scale will adapt to the largest spot size encountered during manipulation of the slider, letting you scan through focus and view the smaller spots on the same scale to give a better visual impression of how much the spot size is changing. Pressing the Disable button requests all open diagnostic windows back to the default autoscaling mode.

For best response have only as many windows open as you need. In particular the Surfaces editor window is best closed before using sliders becuase a lot of horsepower is expended to keep the user interface up to date.