Wonderful to find rail sweep as a SketchUp forum topic. I am a flying scale modeler desiring to utilize SketchUp to generate 3D image files with which to CNC mill components which would otherwise be too difficult to create via hot wiring Dow Highload 60 Styrofoam.
While I am no stranger to either CAD or utilization of foam with respect to creating an accurate scale model for competitive flying use, I desire to reduce my dependency on the use of another person to do what I consider baseline lofting...yet continually turns into more than a challenge to get someone else to complete in a timely fashion. Key word, timely 
I have been creating scale aircraft from photographic and line art renderings for 40+ years. This has me creating cross or half-cross sections of an aircraft's fuselage or other airframe component and aligning these along the length of the airframe from nose to tail, and left to right across the beam.
A series of datum lines provide alignment guides fore to aft and each cross section has a vertical constraint of the perimeter of a line drawing along which the cross or half cross section is positioned...following aircraft manufacturer's bulkhead/former station index. These indexes typically begin ahead of the airframe at 000.0000 and end beyond the rear most point of the airframe to enable a grid across which an airframe evolves...aka grows in length and width.
An example of my master for railing appears below: There are two desired railings in this master drawing workup. (1) The frontend from just ahead of the wing intersect with the fuselage, (2) The rearend from ahead of the intersect with the vertical fin and fuselage to the rear of the plane. The airframe is divided into milled and hotwired sections. The fuselage has the two (2) milled sections described above.
As you can see we strive to be as accurate as possible. Unfortunately, with this aircraft there are only two surviving engineered drawings. All other drawings are artist renderings. Most people don't realize manufacturers rarely create a composite drawing to scale. They create marketing composites but almost never draw a composite with actual scale proportions.
Typical aircraft drawings often referenced as threeviews/3VUs/three-views, multiple view drawings are not accurate enough to create a model from. A common problem is lengths and widths of each drawing perspective does not match others shown in the same drawing 
I know that may shock many of you...its not often I find people who bother to compare one dim from perspective to perspective...
Ultimately, I desire to loft to a solid which can be "edited" in SolidWorks 3D as that is the typical tool used in an industrial environment where CNC milling occurs.
Can someone take a moment to reply as to how this can be achieved with SketchUp, either the freebee or Pro with a "minimum" of manipulation... Key word, minimum.
Literally, I would like to go from a 2D compilation into a another editor to render it a transparent .tif...or other format, then place each half for full cross section along rails at an explicit location left to right with the side view of the airframe component laying beneath the rails for alignment purposes...(fore~aft and a from above or below view (when necessary). "Then" let SketchUp loft/rail/render/extrude...which ever term you wish to call it.....yield a multiple dim 3D solid image.
Thanking you in advance for your valuable time... 
As a point of reference I provide a dims index for the two B-47's I am constructing. I hope this tends to put some meat on my inquiry so you guys don't think this is BS.
Please, instead of plopping down an app or workaround name...please explain how they can achieve what I desire to achieve. Remember this is to occur "all" within SketchUp as a best practices solution...
There are 2 airframes to portray 3 Boeing B-47's... Think about that for a moment...
The 1000th #1 below, and #3 are to be the same base airframe with exchangable components permitting two completely different BuNo aircraft to be represented with a single model.
This is being done to permit me to expand upon the flight plans of the "typical" mission flown by the B-47 to include the two most unique maneuvers flown with these aircraft. The B-47 was the United States' first jet bomber and the first production swept wing bomber.
The L.A.B.S. maneuver is the Low Altitude Bombing System
