Lithophanes and Tinkercad
People have been making lithophanes for hundreds of years out of ivory, porcelain, and wood. They are formed by intricately carving a single-color piece of material, then backlighting it so that subtle differences in light and dark are created by the depth of the material. This page explores the process I use for 3D printing lithophanes, including adding to them with standard Tinkercad and Codeblocks.
The lithophane here is of Shirley Chisholm (1924-2005), the first black woman to be elected to congress, and the first woman to participate in a presidential debate. She served for seven terms in congress where she worked on food security, labor rights, and child welfare, among other issues.
The original image is from the Library of Congress. The lithophane ranges from .2mm to 2.9mm in thickness. The background design was coded with Codeblocks and is meant to reflect the pattern on Chisholm's blouse.
Nina Simone, jazz artist and activist.
Toni Morrison, Nobel-winning author.
The directions here assume a basic level of comfort with standard Tinkercad. If you run into points of confusion, Tinkercad has good learning resources, and feel free to reach out to me. I'd also love suggestions about how these directions can be improved.
1) Import a photo to the Image to Lithophane tool at http://3dp.rocks/lithophane/ by clicking on Images, then Import. This is a great resource, and I support it with a monthly Patreon donation. There are different form factors that you can choose from. I'll be working with a flat design.
2) Under Settings, go to Model Settings. Here you can specify the size of the longest dimension. For thickness, I have tried from 2.5 to 3.5 mm. The lighter the filament color you plan to print in, the thicker your print can be. The Border slider lets you create a frame around the lithophane if you wish. If you plan to print directly, then you can select a frame width if you want. If you plan to import to Tinkercad, I recommend leaving it at zero border. I also set the thinnest layer to .2 to .4 mm. Finally, the base / stand depth slider lets you add a base to the front or back if you wish. If you use that, I’d recommend a base in front so you can print the lithophane on its back and get better quality.
3) Also under Settings is Image settings. The only one I use here is the positive / negative image slider. I make sure it is on “positive image.”
4) Back on the Model tab, be sure to hit the refresh button so that your changes are visible. You can then download the stl file, put that in your slicer program and get ready to print the lithophane as is. Be sure to use a high quality setting to print, which means a small layer height, like .1 mm. Also be sure to use 100% infill.
In this print, I forgot to use 100% infill. The dark shirt is the thickest part of the print, so the slicer used 20% fill there, and you can see the cross-hatching. Luckily, it looks like a shirt design.
The thickness of the print impacts the image. The print of Toni Morrison on the left is 2mm thick while the one on right is 2.9. In the left print you can begin to see a bit of the detail of her sweater, but it looks solid in the right print. However, the tones seem a bit richer with the greater range that the extra .9mm gave the right print.
5) To work on the lithophane in Tinkercad, open up a new project in Tinkercad, click Import, and navigate to the lithophane file you downloaded. It will take a good 10-30 seconds to download because there is so much going on in the lithophane file.
Tinkercad often has trouble with lithophane imports to one degree or another, and they differ on each import. I usually find that at the very least, the edges of the lithophane are a little flawed, and sometimes it's pretty dramatic. It's important to inspect all edges from the sides and underneath to see if there are errors that will cause the print to fail or look bad. The easiest fix is often just to drag on a hole to trim off the flawed parts of the lithophane's edges (fourth image below). You can sometimes also fill in missing elements. If the flaws are a real problem, try importing again to see if they disappear (/ are swapped for other flaws).
6) If you'd like to use a Codeblocks design, keep reading. If you'd like to only use standard Tinkercad, you can add elements to make a frame around the image or incorporate it in some other design. Remember that when you export to print, it will take some time to process your creation.
Following, we'll look at how to incorporate a Codeblocks design into your lithophane. See my page on Codeblocks for ideas on how to create designs.
Once you have a design, click Export, then click Part. You'll be asked to name the part.
7) Back in your standard Tinkercad lithophane design page, go to the drop-down arrow on the right hand menu and navigate from Basic Shapes down to Part Collection. There you will find your Codeblocks design. It's now available as a shape that can be treated like any other; it can be resized, turned into a hole, etc. Remember that holding down the shift key when you resize lets you scale the entire object up or down in proportion.
8) For this print, I knew I wanted just half the Codeblocks design, so I grouped it with a rectangular hole to cut it in half.
9) Get the Codeblocks design ready for integration with the lithophane. A design with a flat bottom has the best chance of printing reliably. Many shapes will have flat bottoms. However, if you are using a torus, consider the image below. The orange and green tori are identical, except the green has 6 steps rather than 16. That means it retains some interesting facets, and it makes it much more likely to print successfully. To make either shape even more likely to succeed, I would raise the height up to 40, then drag on a hole box with a height of 20. Expand the hole to be greater than the Codeblocks design, then group the two. You've now cut the torus in half and given it the widest and flatest possible base to print on. Lower the trimmed design back to the workplane. (If your print still fails because it's too narrow, try increasing the "tube" component of the code to make it thicker. )
10) Now you're ready to align your trimmed / cleaned up lithophane with your Codeblocks design. Use the align tool to help you get everything where it needs to be. Adjust the height of the Codeblocks design as well. I decided to make it the same as the max height of the print, which was 2.9 mm.
11) Even if your Codeblocks design is very thin, it's still thicker than the thinnest part of the lithophane, so it would stick out (maybe a cool effect?!). Here, I want the Codeblocks to not be visible but to overlap a little to ensure that there is a good connection when I go to print. What I do is use a hole to cut out a shape in the Codeblocks design that is just barely smaller than the lithophane. To do that, drag on a box / hole and size it to just less than the lithophane. You can click on a corner of the lithophane and get its dimensions, then make a box / hole that's a tiny bit smaller, or you can eyeball it. Remember that you can adjust your increments of sizing change from the normal 1 mm down to .1 for real fine-tuning.
12) Click on the Codeblocks design, then shift-click on the hole and group them together. It should cut a hole that is a tiny bit smaller than the lithophane, as pictured.
13) For some designs, you might be ready to export for 3D printing at this point. If you want to add a base for the lithophane to stand on though, now is the time to do it. Below, I added a round roof shape, rotated it, cut it in half with a box / hole, lowered to the workplane, then resized it. Other shapes would work as well.
14) Another idea is to design your own base that's separate from the lithophane. This can be a good challenge for students, and because a small base prints pretty quickly, it's easy to iterate and improve on a design.