Summary

This is a key fob based on Tux, the Linux mascot.
It is part of a book on how to design objects for 3D priniting using FFF/FDM machines.
The book will be available soon from Sylvania Books and Amazon.

Instructions

This example generates a simple object from a 2D artwork. The following tricks also work with text.

In this case the objective is to create an artistic key fob using the freely available image of Tux, the Linux mascot. Tux was created by Larry Ewing in 1996. This image was downloaded from the internet under a creative commons licence allowing unrestricted use. As can be seen, the image is not continuous around the edges and the lines are very thin in places. This means that we will need to modify the image slightly. This is easily done using almost any image editor. Do this before continuing.

Our key fob design will be circular and the dark areas of Tux will be raised up. The overall size should be a fob of about 50mm diameter with a small hole for a ring. At this stage it is not clear exactly how big the graphic will appear but we would like it to make up the majority of the fob area.

Instructions

• Start off by specifying the size of the page in Inkscape to be just 100mm x 100mm. Click on File -> Document Properties... and then enter the appropriate dimensions for width and height.

• It is a good idea to then zoom to see the whole page. This method allows you to get a feel for the overall size of the design even though it is not really an accurate way of designing things.

• The next stage is to import the revised graphic into Inkscape. You may need to select the 'embed' option. Click on File -> Import and select your favourite Tux image. Or simply drag the file onto the page.

• The image will almost certainly not fit. Resize it as needed. Drag the resized image into the centre of the page. Guess roughly the size needed to make it about 50mm square and try to maintain the original aspect ratio.

• Use the 'select' tool to select the image of Tux in Inkscape

• Click on Path -> Trace Bitmap to convert the image to a vector graphic. My original file was in a *.gif format and this method worked for me. Remember to remove the original graphic which will be underneath the traced one.

• Select suitable thresholds. The default values work well for monochrome graphics. Some experimentation may be needed for other designs.

• Click on Path -> Object to Path. (Inkscape doesn't confirm this operation).

• Click on Extensions -> Generate from Path -> Paths to OpenSCAD.

• Select a suitable output file name and save the generated OpenSCAD file.

• Close the dialogue window.

• Open the output file in OpenSCAD and view the result so far.

You should now have an OpenSCAD file containing a lot of coordinates which represent a 3D extruded version of our image. Of course although you could go ahead and try to print this it would be nice to mount on a suitable base and maybe add a few embellishments.

The simplest thing to do is to continue with OpenSCAD and add a circular base and small hole for the key ring. See the section on how to use OpenSCAD. Simple additions could be a hanging loop and a circular base as shown in the OpenSCAD code.

// ADD THIS CODE TO THE END OF THE
// FILE GENERATED BY THE INKSCAPE
// “PATHS-TO-OPENCAD” SCRIPT

difference()
{
union()
{
// Generates Tux Logo 5mm thick
output(5);
// Adds base plate, 3mm thick
cylinder(r1=25,r2=25,h=3);
// Adds hanging tab, 3mm thick
translate([0,-25,0])
cylinder(r1=5,r2=5,h=3);
}
// Adds hole in hanging tab plate
translate([0,-25,0])
cylinder(r1=2,r2=2,h=3);
}

You can now compile the OpenSCAD file using F6 and then export the STL file to your favourite slicing engine to generate the G-Codes for printing.

Tux Logo Key Fob