Do you know, that… ?

Drawing the different elements by means of splines,, sooner or later it will appear on the contact of the two splines at the connection point.

How can this affect, spline which remains unchanged, and which to adjust to the specified? In the example below there are three segments spline.

I want to be tangent, but in such a way, to the upper spline adapted to the spline on the left and at the same time that he has adapted to the lower spline.

If I add relationship tangentially at the upper, it still remains a top spline and change the left side.

If the order by adding condos tangentially the bottom, changes spline bottom and not in the shape of an arch.

So to achieve the goal of doing so. I grab for handle spline upper left him and I add relationship Constant. Do the same with a long handle lower spline. Then I add 2x relationship tangentially and at the end of the relationship absenting Constant. Of course, after removing the contact does not change.