Parameters are dimensions or numerical constants that have been given a variable name and are used to create parametric equations between pieces of geometry. While dimensions always have a numerical value, parameters may have a numerical value or a value resulting from a mathematical expression. For example, you can parameterize the radius dimension of a circle so it will always be half the size of another dimension in the sketch, but you must first associate both dimensions with parameters to create the expression. You can use the sketch options to control whether ABAQUS/CAE displays the names or values of parameters in a sketch (for more information, see “Customizing the format and use of dimensions in the Sketcher,” Section 19.9.7).

Parameters must be defined within a single sketch—you cannot define parameters in one sketch and use them to create expressions in another sketch. Defining a parameter adds it to the Parameter Manager for the sketch. The order of parameters in the manager indicates the order in which they can be used in expressions. Figure 19–7 shows two parameters; the length parameter is used to define the width parameter. If you instead wanted to define the length in terms of the width, the width parameter would need to appear first in the manager. You can use the buttons on the right side of the dialog box to create parameters by selecting dimensions from the viewport or to insert, move, or delete parameters from the manager. For detailed instructions, see “Adding and editing parameters,” Section 19.12.5.