Autodesk Inventor iDoor Tutorial
Page 2 - Constraining the Sketch and adding parameters.
| Tip; if you have a different color scheme than mine (you almost defiantly do) and want a white background so things look the same, download this background file and use the short Background Image tutorial to apply it. |
Once you have the rectangle drawn, you will need to center it relative
to the origin point. The easiest way to do this is by using Horizontal 
and
Vertical 
constraints located near the center of the ribbon on the Constrain panel as
shown below.
Select the Vertical Constraint
from the Constrain Panel 
of the ribbon and hover your cursor over the
Center Point 
until it turns red, then click. Then move to the center area of the
topmost horizontal line in the rectangle until you get a little green ball
that indicates you have found the center, and click there as well to
complete the vertical constraint. Depending on how far off from being
centered your rectangle was, it may jump sideways quite a bit to center
itself.
When complete there will be a
little dot on the line at the center of the line 
showing that there is a coincident constraint to the line. Now add a Horizontal Constraint
from the Center Point to the right vertical member of the
rectangle to constrain it as well. The rectangle will now remain centered on
the part's origin, which is good modeling practice in general, but is needed
later in the tutorial.