Shading is a lot easier with pencil and paper. I mean seriously, this would have taken maybe 30 minutes to an hour for me to do this by hand, (just the shading) but took 4 or 5 hours in vector. And I hate clips, they hate cooperating with me.
Anyway, I think this turned out pretty good for my first time shading a vector. I had originally tried using gradient meshes from ponyscape, but I couldn't get those to work well between body parts. I did make some pretty awesome legs though before I changed to just using gaussian blurs and clips to make them. I mostly added shadows, but the front wing, hoof, and hair have some lightening as well.
I think that they light is coming somewhere lined up with the middle of twilight in the air somewhere, but I didn't really do a good job at keeping the shadows in the right places for it to be in any one place. Oh well, that really just means I need more practice.
And that is a big file...nearly 3 times the size of the next largest pony vector I have. (That would be this cupcake
at 3.58 MB)
Unshaded version: fav.me/d6lsx6p
You can download the svg file here
I don't own MLP:FiM or Twilight Sparkle.