From the 3rd Dorkmension

Because I’m a giant nerd, I wanted to use my computer to see how close I was with yesterday’s shadow. Using Photoshop’s 3D function (which I’d never actually touched before), I placed a cutout of my character in a 3D scene and put up a light in roughly the same location I’d envisioned yesterday.

So I think I wasn’t too far off, but I was probably silly to try to show any curves in the long shadow; as this example shows, a shadow like that is just sort of compressed into straight lines.