3d Car Design

I am working on a program that allows for you to build your own custom car from the ground up. First you select basic things like a chassis and drivetrain and everything else vital for a car. You can select one already premade or design your own with the included 3d cad software. Later versions might be able to do animations with working parts and i hope to be able to do calculations which estimate things like top speed, horsepower, and drag coeff. I think i may know enough to do all this, but i need with the engine itself, opengl. I have just learn to use it and i still dont understand half of it. And i know there is more to it than triangles, squares, chading, lighting and filling in shapes. If you know anything about opengl, like how to do lines, circles, spheres, or anything else that could help me, please reply to this thread or email me at [email protected]. Thankyou