Theo's Relief

White PETG - 1400mm x 65mm x 953mm (L x W x H)

SKILLS USED: Solidworks CAD, Adobe Illustrator, PrusaSlicer, FDM 3D printing, Projection

The Idea:
For my next foray into "printing a large thing out of multiple white PETG parts and making it glow" I wanted to try out making Lithopanes. The concept is to convert a 2d grayscale image into different model depths in 3d (so white would be the minimum depth, black would be maximum depth, and with all the levels of gray in between). When this model is printed and lit from behind the different thicknesses recreate a version of that same grayscale image.Taking the concept one step further though, I wanted to exaggerate the depths so the resulting object could stand alone as a low relief sculpture when not lit.

For a subject I picked "Theologue" by Alex Grey. I thought it would be interesting to pick a contemporary artwork that has never existed in 3d.  As I haven't printed the whole thing yet, I'm calling my version "Theo" for short.

The Process:
The first step I took was to upscale the art (sorry Alex).  While this did introduce some artifacts, it created crisper lines and removed the graininess I had trying to make the source image large enough.

Next I cut the image into hexagons and scaled them to both fit the full artwork, while at the same time individually fitting on my print bed. Each hexagon tile was then converted to a lithopane. 

I ran through a few iterations of different minimum and maximum thicknesses until I found what I thought was a great middle ground between a lithopane and relief sculpture. I ended up using a maximum thickness of 8mm.

The resulting model was too large for SolidWorks to handle, so I modeled rest of the the parts separately.

Not only did I create the the physical parts that I was going to print, but I also had to create a "negative volume" that would be subtracted from the lithopane and allow for the tiles to key into the holders.

The hexagon tile holders were pretty straight forward to design, and the final model was locked in quite early.

The hexagon joiners on the other hand went through several revisions. This was partially for the physical joining of the tiles and then more temperamentally, the look of the lighting through the tiles. A crucial part of all of these designs was the fact that they could be printed without supports (although for the integrated thread I had to adapt the layer height for the threaded portions of the model). 

In the end (for the moment at least) I printed 45 tiles - this width covers the 4ft length of pegboard I used as a backing mount and exhausts the lengths of led strip lights I used.

The first part of lighting the finished project is to show off the backlit lithopane aspect. Overall I'm very pleased with the consistent lighting I was able to achieve with the edge on led strip. Also the bezel (for lack of a better word) around each tile is unobtrusive and overall does not catch the eye - I was afraid that there would be a pattern of harsh dark shadows covering the piece.

The next thing I did was use the source image for all my printed tiles and project that back onto the piece. Surprisingly (or perhaps not that surprisingly) it was quite difficult to get all of the grid lines of the projected image to line up with the physical model - the optics of the projector lense and its physical location in space only allowed me to get quite close but not perfect. Ultimately I would be interested in diving into some simple animations and loops to bring aspects of Alex's art to life: pulsing grid lines, pumping circulatory system, flickering flames, and rotating halo all come to mind for example.

The final experiment I tried was a mix of both of the above: projected image onto a backlit surface. The fun thing here was watching as the complementing and contrasting colors of the artwork dance between being more subtle to very pronounced as the backlight cycled through the spectrum. The two examples below show off that dynamic, with blue on the left being more subtle and green on the right being a more exaggerated color scheme.