Click the arrow under the Dimension tool and select Dimension.
Click the Select bodies tool guide on the right side of
the Design window.
Select the solid body or bodies you want to dimension:
If you select a single body, then the maximum horizontal or vertical
dimension is created, as shown below.
If you select more than one body, then the dimension is created for
both solids and is anchored on the side closest to where you click the
solid. You must click the Select bodies tool
guide before you select each solid, so you click the tool guide and
select the first part, then click the tool guide again and select the
second part.
In both of the examples below, the upper part was selected near its
top. The lower part was selected near its top in the example on the
left and near its bottom in the example on the right. The mouse
arrows indicate where the lower part was selected. You will see a
preview of the dimension when you click the tool guide and hover
over the second part.
If you create the dimension in a section view of a drawing sheet, then
the dimension is created on the extents of the body that is visible in
the section plane, as shown below.