Solidoodle doesn't love angles of more than 45 degrees, although it can be done with a fan and slow speeds. Think about how it prints, how it slices and how the material will be laid down from the bottom up as you're designing. If you have something that starts halfway up the part (hands on this model for example) and there's nothing below them, solidoodle will try to lay down filament there, but the filament will just droop down to the bed and most likely ruin your print.
What you can do in your skeinforge or slic3r software is enable support material. This will allow you to print whatever but you'll have to remove the support material when you're done, it will work but won't look as good.