I made a 1/24th scale (aka 1/2" = 1'-0") wooden model first, and then traced photos of it in DataCAD. Then I did orthographic projection from 5 views to make 15 section profiles; separated by 1 foot in Z-height. Then I used the ruled surface tool to connect as much as possible, and then I exported this to SketchUp, using a DWG file. Then, in SketchUp, I built the rest of the surface.
I then revised it several times and simplified the number of polygons, and ended up with a decent looking model, if I say so myself. I've written an entry in my blog, describing the design, and I've included photos of the model, the DataCAD drawing I did, and image captures -- and an animation from SketchUp. Here's my blog entry (updated periodically):
CarBEN Concept EV: An Open Source Project - Vox
And here's the YouTube URL where the animation video is:
My main idea is to have it be as low aerodynamic drag as possible. So, the wheels are fully enclosed, and in order to keep the width of the front as narrow as possible, this will require having the front wheel skirts be articulated -- i.e. when steering sharply, they will move with the steering. At highway speeds though, there will be enough space around the wheels to allow the wheels to move without having to move the skirts. The skirts will not move with the suspension, as this would be too much unsprung weight, and it would create more problems then it solves.
My hope is to do some CFD testing on a computer, but so far, I have not found a way to get the SketchUp model into a CFD program. They require a "solid" type model; as opposed to a surface model that SketchUp creates. My blog entry goes into how I hope to build it (similar to a monocoque airplane,); though composite construction would lend itself well, too, I think.
I'm hoping to eventually use a supercapacitor for regenerative braking (like the Carnegie Mellon "Charge Car" project). And I'm hoping to use regenerative shock absorbers, like the ones that were just announced from a company called Levant Power:
Shocks that can save fuel, charge batteries and propel vehicles down the road? — Autoblog Green
If and when I get the rolling chassis built, I'm sure I'll be looking for lots of input on the battery pack and the drive system. I'd appreciate any and all comments you may have on the overall concept, as well.