The "World Cup" Lithomap

thingiverse

This set of C source tools generates lithophanes, 3D models made from images that reveal an image when lit from behind. The "lithophane" tool creates traditional lithophanes in STL format from ppm-formatted images (convert other formats using ImageMagick). Meanwhile, "lithocup" produces lithophanes mapped on cylindrical surfaces, like the included "World Cup" lithocup which unveils a map of Earth when lit from within. Several updates have been made to these tools, including adding a "margin" option on lithocup for continued cylinder past edges and changing orientation options. Binary STL files are now an option with the "-b" flag, while a new "margin" (-m) option is available on lithophane for creating image borders. The "chamfer" (-c) option on lithophane chamfers corner borders to prevent lifting during print. Another version of lithophane, "lithosphere.c," generates lithophanes from spheres. However, it requires validation with a physical print. Recent updates fixed incorrect image orientation and provided new images in the correct orientation. Instructions for compiling the C file are found at the top, with lithophane and lithocup help lists accessible via command line. Input files must be PPM-formatted, and ImageMagick can convert other formats to PPM. Outputs from both programs are STL files, ready for slicing. Be cautious of large outputs that may overwhelm a slicer, or use the "--factor" argument to downconvert images. The balance between lithophane resolution and file size is crucial. A World Cup lithocup was created using an image file of a cylindrical earth projection and the command: "lithocup -y1.8 -a360 -f2 map_image.ppm world_cup_3.stl." The "-y1.8" scales the cylinder height, "-a360" generates a full cylinder, and "-f2" downconverts the image while reducing file size. The C code is open-source under GPL license.