Under insert; annotations; centerline, or by picking the centerline icon on the annotation toolbar. You can create centerlines by picking two parallel lines. This will put a centerline between the two lines you pick. When the centerline is there you can select it and drag the ends as far as you would like.
On the side view of the drawing you must select the 2 lines the make up the circle, the on the annotations tool bar select the centerline icon and it will place the center line between the 2 lines you selected.
Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats.
--Howard Aiken, IBM engineer
There is no centerline icon/button on Annotations toolbar, though there is Centermark. Is this feature only available in recent versions? I am using 01+
In your 2D drawing add a layer called Centre with line type set to Centre and a designated colour (similar approach to AutoCAD). Make this layer active. Draw a line using the sketch line icon tool (or Tools/sketch entities/line).
I recall doing this when I used SW2001+. My drawing templates are set up this way and I have successfully used this approach ever since, including SW2005, when I require centrelines.
![[pc2]](/data/assets/smilies/pc2.gif "[pc2] [pc2]")
