Using a few open source software tools and very little technical knowledge, it's possible to turn a 2D vector drawing into an extruded object for 3D printing. I used this technique to make a bracelet.
- Make an .svg file of the shape you want to extrude
- Convert it to OpenSCAD format using an Inkscape extension
- Use OpenSCAD to render and generate an .stl file
- Print the object