Menus > Number Menu > New Parameter

This Number menu command creates a new parameter in your sketch. A parameter is a number that can easily be changed. It’s convenient to use parameters in places where you need to have a number but want to be able to change that number easily.

The keyboard shortcut for New Parameter is Shift+Ctrl+P (Windows) or Shift-P (Mac).

Use parameters in calculations, in functions, and as values by which to transform objects. For example, you might create two parameters, named m and b, and use them in plotting the function y = mx + b. Or you might create a parameter that varies from 0° to 360° and use it as a marked angle to rotate a polygon.

When you type the initial value, the number of decimal places you type determines both the precision and the keyboard adjustment, as shown in these examples:

Initial Value	Decimal Places	Displayed Precision	Keyboard Adjustment
5	0	units	1
5.0	1	tenths	0.1
5.00	2	hundredths	0.01

The keyboard adjustment is the value by which the parameter changes when you select it and press the + or – key.

To change an existing parameter's keyboard adjustment, choose Edit | Properties | Parameter.

To show or hide an existing parameter's edit box, or to change its displayed precision, choose Edit | Properties | Value.

When you choose New Parameter, a dialog box appears.

Name: Type a new name for the parameter. If you want the name to include a subscript, enter the subscript within square brackets. For example, the default name t[1] appears as t1 in the sketch.

To change the value of a parameter, you can double-click it with the Arrow tool, use the Display | Animate or Edit | Edit Parameter commands, or create an Animation action button.

Value: Set the initial value of the parameter by typing a value in this field.

Units: Choose whether the parameter’s value uses no units, uses the current angle unit, or uses the current distance unit.

Parameters and Sliders

To create an easily modified numeric value, use either a parameter or a slider. A parameter is easier to create, and you can adjust it more precisely and easily animate it over a specific numeric range. A slider is harder to create, but you can manipulate it easily (by dragging the point at the tip) and control it in a continuous and satisfying way.