If anyone knows an easier way of doing this - please add in below.
Software needed
- Inkscape - An open source vector graphics editor, with capabilities similar to Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format.
- OpenSCAD -The programmers solid 3D CAD modeller
Steps
- Get a 2D image and open it in Inkscape (or draw it in Inkscape)
- Convert it to a path (if it worked you should see a bunch of grey squares)
- If it is a found image go to Path --> Trace bitmap - shift+Alt+B
- (if you drew it Path--> Object to path or click Shift+Ctrl+C)
- Select every node -- go to Edit --> Select all or Ctrl+A
- If you want a high resolution (curved lines) then click the far left button "insert new nodes into selected segments" (do this as many times as you like 2 or 3 times gets pretty smooth curves on most images
- Then click the "Make selected segments lines" button - see screenshot (if you can not see the buttons click F2.)
- File -->Save as a dxf file
- Either save the file into your OpenSCAD directory or move it after you save it
- Start OpenSCAD
- Use the import command in the directory you saved it in. If not on your own computer (e.g. Principia computer use:
import(file="\\\\principia.edu\\home\\My Pictures\\filename.dxf", convexity=3);
- then you can use linear_extrude () ;
- Compile and Render it (F6)
- Save as STL for printing: Click Design --> Save as STL (this could take some time depending on how complex your object is)
- Open in your favorite 3D printing software and have a go at printing it
If you want to import an stl into OpenSCAD:
import("name-of-file.stl",convexity=3);
Alternatives
For a real-world item such as a photograph, an alternative is to use a group of images/photographs taken at a slightly different angle and with varying points of focus.
Using the open source software VisualFSM you can convert the collection of images into a 3d cloud of point data - which can then be edited on Meshlab before printing. See here a tutorial on how to do it.
Free cost but not open source: http://www.selva3d.com. Upload your file and it is converted to STL following 3 steps, without the need to download any software.
Another free cost, but not open source alternative is http://web.archive.org/web/20170401174609/http://www.123dapp.com/catch.