General

A parameter is a specific element. It contains an integer or decimal value and can be referenced by the associative elements. A center radius circle, for example, is an associative element that makes reference to a point element driving its center and to a parameter element driving its radius. A modification made to the value of a parameter causes the updating of the radius-center circle.

A parameter can be referenced by several elements, in the case we say that it is shared. If several radius-center circles share the same parameter, a modification made to the latter causes updating of all the circles that reference it.

All integers or decimal values that play a part in the definition of elements are not all parameters. The basic elements contain the values required for their computation (a basic circle contains a radius and an angle) but these are not parameters. These values cannot be shared with other elements.

Type and units

A parameter has a type and units. The type indicates which kind of physical measurement it represents: a length, an angle, a speed, a temperature, etc. The units indicate in which units the value is expressed when it is presented to the user: a length parameter can be displayed in meters, in millimeters, in inches, etc.

You can create a parameter using the Tools - Parameters function. The different functions ask to name the parameter. This action is necessary. If you do not specify the units for the parameter, the current units corresponding to the type will be the units for the parameter. You can however specify the units explicitly:

Create a length parameter with a value of 13, if the current units for length is mm, then the parameter's value is 13mm.

Under the same conditions, you can specify 13in to create a parameter of 13 inches or 13 m to create a parameter of 13 meters.

It is also possible to create parameters during the use of a function. Either in the graphic label, or by clicking on the button in the entry field for the value of the function and choose the parameter to create.

You can name directly a parameter (R=10): a parameter is created and named.

You can also enter an expression (a+10): an expression type parameter is thus created.

Lastly, you can use a parameter that already exists, either by entering its name, or by designating an element or part of an element directly linked to a parameter that you are seeking: you can also show a face resulting from a fillet in order to recover the value of a fillet (a link is thus created), you can designate a polar point in order recuperate one of the two parameters for length or angle.

The current units linked to the principal dimensions are modifiable at any time thanks to the File | Properties function. These default units are stored in the memory, document by document.

Parameter without units

You can create particular parameters without units. These parameters are used to represent numbers of occurrences and coefficients. These parameters can be used as number of repeated elements.

Otherwise, you can't use a parameter with a dimension to represent a number.

Parameterized system properties (description, part number, ....)

The description or another system property can display a parameter value (for example the length of the part) and change if the length changes.

For example, the description of a part must be like "Axis Ø20 x 100" where 100 is the length of the axis (its parameter is for example L).

In the entities tree, unroll the Parameters folder, then the System parameters. Richt click on the Description property, select the Others > Parameterized and enter the description: Axis Ø 20 x [L]