While in Add Constraints mode
, you
can constrain the center of a circle to the contour of a spline.
Note: You can also dynamically
modify spline slopes in Select 
mode.
To constrain the endpoint of a line to a spline:
Click the Add
Constraints icon , from the Sketcher
toolbar.
The cursor changes to a black pointer and
cross-hair. 
.
Click on the spline. Dashed lines representing the slopes at either end will appear.
Note: The direction of the slope depends on how the slope was defined; the slope proceeds in the order in which the spline points were picked.
Click the endpoint of the line and click the Coincident
icon 
in the Constraint
toolbar
The endpoint of the line is coincident to the spline and can be moved along the contour of the spline in Select mode accordingly.
