Creating Driving Dimensions

This task shows you how to create dimensions that will drive associated constrained geometry.

Go to Tools -> Options -> Mechanical Design -> Drafting -> Dimensionand select Activate analysis display mode. Then, click theTypes and colorsbutton to define the characteristics that will be assigned to constrained geometry.

The Types and colors of dimensions dialog box lets you select the color you want to assign to driving dimensions. Select the color shown below, for example.

Click the Dimensions

icon from the Dimensioning toolbar and create a dimension on the geometry previously selected. In this example, create a length dimension on a line.

1. Double-click the dimension.

2. Modify the dimension via the displayed Dimension Value dialog box. For example, enter 40 millimeter as the new length. This dimension will now drive the geometry.

If the Drive geometry option is selected, the double-clicked dimension becomes a constraint and behaves as a dimension constraint.

The geometry is updated in order to reflect the new driving dimension. Let's call it driven geometry.

In addition, this geometry is assigned the characteristics previously defined in the Types and colors of dimensions dialog box via Tools -> Options. In this particular case, the driving dimension is visualized as follows:

You cannot create driving dimensions in the following cases:

	Between a generated element and an interactive element, horizontal and vertical dimensions are not available. If you double-click on the dimension, the `Drive geometry` option is deactivated.
	Between an interactive element and a generated circle center, no type of dimensions is available. If you double-click on the dimension, `Drive geometry` option is deactivated: To bypass this problem, create a point that is concentric with the center of the circle and create the dimension between this new point and the other element.
	Between two elements (a generative one and an interactive one) that are not parallel, no type of dimensions is available. If you double-click on the dimension, `Drive geometry` option is deactivated: To bypass this problem, create a point that will be coincident with line A and line B at the same time and create the dimension between this new point and the other element.
	Between two semicircles (apart from dimensions between the semicircles centers). If you double-click on the dimension, the `Drive geometry` option is deactivated: