Parametric dimensions are a type of constraint in the sketch environment. Parametric dimensions control the size and position of geometry. Dimensions are created automatically when you enter values in the input boxes during geometry creation or manually using the General Dimension command.
Edit a dimension to change the size of the associated geometry. Dimension values can be expressed as numeric constants, as variables in an equation, or in parameter files.
You can edit sketch dimensions before or after a sketch becomes part of a feature. If a sketch has not been consumed by a feature, its dimensions are visible and can be edited. After a sketch is consumed by a feature, select the feature in the browser and activate the sketch for editing.
The number of dimensions required to fully constrain your sketch is displayed in the lower right of the interface. Use dimensions or constraints to continue to define your sketch. If a dimension overconstrains the sketch, you can accept or cancel the dimension. If you accept the dimension, the dimension is saved as a reference parameter. Its value is enclosed in parentheses and updates in response to changes in normal dimensions.
You can change the display style of dimensions. Select the display style from the status bar at the bottom of the interface. Choose from Value, Name, Expression, Tolerance, or Precise Value. Dimensions calculated by equations (where, for example, d5=d2) are displayed with a prefix of "fx."