Aside from hiring a 3D modeler to make your designs so that they can then be 3D printed by Shapeways, you can, if you're adventurous, become a 3D modeler. The easiest software to learn that has the most modern advancements and is steadily becoming the most robust as well is SpaceClaim. There is a reduced function version of it you can use for free
found here. Once installed you simply click on File >> New and your ready to start. You make 3D designs most of the time by drawing them first in 2D. When you start a new design it automatically starts out in the 2D mode. Just draw the profile of your design in 2D using the 2D drawing tools you see above. Then to make the profile into 3D you simply click on the Pull Tool in the top center. That makes your 2D profile turn into a 2D face and if you click on the face you can then pull it into 3D. That's it! Around 80% of 3D modeling is repeating those simple steps and then connecting the 3D parts together to make the final object!
EDIT: Typo
Last edited: Apr 30, 2016