As I think this purpose can be for a general interest, I open a special thread into this Tutorial Section to explain my way to achieve this.
Didier Bur [Plugin] Projections version 2 UPDATED 03.07.09
Matt666_Selection manager
Jim_Selection Memory
tmtm_Selection Toys (1.4.0)
Weld by Rick Wilson
Fredo_BezierSpline
Native FollowMe tool is overpassed with this kind of 3D curve job. It makes the shape rotating along the path.
Some other solutions exists.
I have tried: wikii_FollowMe and keep But in our case, the result does not suit..
We can also use Kirill _ 2 Faces + Path following this kind of method: Copy Array Along Path tool...have a look.
but this exercise is hard for it too.
The last solution to make our shape follow our curves resides in Extrude along a path from 1001bit tools.
This one also need to be tamed. For example it absolutely doesn't like to initiate on a vertical line..
(29$ seems to be a reasonable price..)(traduction française par notre frenchy Pilou
)1001bit.com - Architectural Tools for Sketchup
Once this new ExtrudeAlongPath along these prolonged curves is done, we put the shapes in coincidence two by two for IntersectWithModel and cleaning unwanted. Then the three curves and center references are put together to produce a clean basic roof element component.
clf_Shape Bender
The dome previously drawn with FollowMe tool is painted in glass material and put in place easily with the centered construction point..
My first serie with Kerkythea
simon 
completely mad...
simon
)
simon