Hello, I am trying to find tangent curves to surfaces (pipes) in order to place the correct position of a roof; you can get the idea taking a look to the images 01,2,03.

I explain my method of work:

- Extend some reference line. I intersect them with the pipes to find some sections. After that I draw a line connecting the center of the circular sections and finally i make a perpendicular line to the circle in order to find the point of tancengy. However I am not sure if this way of finding this points of tangency is correct. (you can check image 04)

- I create a line connecting 2 points of tancency and i create a plane. (image 5)

- I intersect the plane with the pipe in order to find the tangent curve to the pipe. (image 6)

What do you think about the process? Do you know some other way more precise or just the correct way to find this tangent curve?

Thanks in advance.