A few weeks ago I designed a Christmas decoration: a small angel with some movable parts. The result was awesome - check out this little movie I made from it [2.4MB Quicktime]. In this short tutorial I'll teach you how to make a similar design yourself. All the necessary files (included the full Christmas angel) are included at the bottom!
The software I used is Inkscape and Blender (both free and open source software), but the steps are similar in other applications.
First create the basic shape as a curve. I drew my original off a photograph that I imported first. Make sure it's perfectly symmetrical - add a few guides if necessary.
Next duplicate the shape and scale it down so that we get a nice outline. Inkscape offers a function called a 'Linked offset' that we can use - it'll create a copy of your curve that you can slim down (which is nicer than just scaling it). Select 'Select Path > Linked offset' from the menu and drag the control point to scale the curve.
Repeat this a few times to get an even number of curves:
Now we'll combine the curves into areas. Select the outer, then the inner shape and select 'Path > Exclusion' from the menu. Use a fill color to check the result,Export the image to a vector file format that you can import into your 3D application.
Import the curves, extrude them and apply a bevel to the curves. Even if you can hardly see it in the printed result, it will have a nicer feel to it.
Add hinges and make sure they're perfectly aligned along the same axis. Here's a screenshot of the hinges that I used, with measurements.
The design is simple; the only thing to tell is that I left a few gaps on the side to make it easier to remove the support material. Please keep in mind that I designed this model for our White Strong & Flexible material; other materials may need a larger air gap inside the hinge.
That's about it. Don't forget to share your results in the gallery or on the forum - we'd love to see what you created!