I might have mentioned this back in 2007. Apologise.
I had the good fortune of 40-hours formal training, and many decades of enjoyable drafting / engineering graphics on my crazy projects.
If you're experimenting with and 'drawing' car modifications, and are not acquainted with the french curve, this video is a good introduction.
You may also want to check out 'ship-sweeps,' and 'ellipses.'
CAD, AutoCAD, and CAD-CAM software will have tools which will generate smooth curves between points.
A french curve and the two other tools mentioned can help provide the same function for 'old-school' experimenters.