Autodesk is my favorite software company when it comes to 3D Design. Autodesk Shapeshifter is a website where you can quickly design a model to be printed with a patter about it. The process is easier than you think, and yet there is still a lot of control that you can choose for the shape of the model (don't skip the advanced controls on the right hand side). I have used this site to make gift napkin rings to just a general shaft on a lamp. I highly recommend it.