If you had a specific design in mind, it might actually be more satisfying to generate the STL triangles directly. You can fit your parabola in 2D (by, say, com

If you had a specific design in mind, it might actually be more satisfying to generate the STL triangles directly. You can fit your parabola in 2D (by, say, computing reflection angle to a fixed focal point), then just rotate and dump out STL. The wiki has a nice intro to the subject: https://en.wikipedia.org/wiki/Parabolic_reflector https://en.wikipedia.org/wiki/Parabolic_reflector