Yes, I'm using Fragmotion to create sprites of the 3d model, they are rendnered from a distance so they already have the right size:The feet look odd, since they're drawn at foot level rather than at camera level (they should look more like this, only for the front and diagonal front frames though). The spikes also could use some smoothing or something to make them look less jagged, on the side frame. Aside from that, this is by far the best Modern Sonic I've ever seen in SRB2, and I wish you the best of luck!
...I have to ask, though, did you use a 3D model as a guide? This looks incredible.
after that, I color the sprite in different colors(it's different colors so that I don't miss a pixel of the original color) and then add the shading and everything.