Here is how I make sprites in Strata3D:
1)Create your ship.
2)Use the animation tools to define that your "movie" is going to run at 36 fps - read the manual section on animation if you don't know what I mean.
3)Define your movie as 1 second long (36 frames).
4)Rotate your ship 10 degrees each frame, so that if you loop the animation, it appears to rotate continuously.
5)Render all the frames at whatever size you want the final ship to be, and save them as a series of pict files.
6)Use a sprite making program to stitch the picts together.
To create the mask:
1)Bump the ambient light up as high as it will go, and fiddle around with your texturing and such until your picture is a white outline of the ship on a black background.
2)Turn antialiasing OFF.
3)Follow steps 5 and 6 above.
Hope this helps. This is how I create sprites, but do it however feels best. Satisfaction not guaranteed, your mileage may vary.
------------------
What the BBC has to say regarding Pikachu:
"That's the one that looks like a mouse on steroids with a lightning bolt up its bottom".