Hellraiser Cube Gears

thingiverse

You know, for kids! This is a remix of the Lament Configuration graphics from the XScreenSaver "lament" module (by Jamie Zawinski), processed by the PLA Gear Kit (by whpthomas). The file xscreensaver-5.36/hacks/glx/lament.c contains the following license text: /* xscreensaver, Copyright (c) 1998-2014 Jamie Zawinski * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that * the above copyright notice appear in all copies and that both that * copyright notice and this permission notice appear in supporting * documentation. No representations are made about the suitability of this * software for any purpose. It is provided "as is" without express or * implied warranty. */ How I Designed This Prepare the cube model Collect images for each of the cube faces. I manually divided the lament512.xpm file into six JPEG images, but you can use images from anywhere you like. Make the final images black and white and as sharp as you can. These will be stamped into the side of the cube model. When I did this I prepared the images so that 100% white indicated where the design should be fully carved into the surface, and 100% black indicated where the surface should be left alone, but then I later mistakenly generated the displacement so that the white parts were left alone and the black parts were raised out of the surface. More about this later. I think it worked out okay in the end though. Go into Blender and create a cube. Repeatedly subdivide the edges until all faces have been replaced with a very fine mesh. Select the mesh on each side individually and create a vertex group for each one. You will need the vertex groups to use the Displace modifier. Now add one of your cube face images to your Blender cube as a Displace texture. Go to the Image Sampling panel and bump up the image sampling Filter Size to 5, this seemed to help with the quality of the displacement. Set your Image Mapping Extension to Clip, so that you won't be working with a repeating texture. Add a Displace modifier to your cube, using the vertex group that represents the top of the cube (that is, the face entirely in the +Z space) and the texture you just added. Set the direction to Z. Set the Midlevel value to 1.0 (meaning that a value of all-white should be left alone) and the Strength to -0.050. Since all of the non-white pixels will have a strength lower than 1.0, they will have a negative displacement, but since Strength is also negative, this should result in the darker parts of your image being elevated along the positive Z axis. You could also have inverted your image colors, set a midlevel of 1, and used a positive strength value to carve your design in the negative Z direction, but by the time I realized this I was already done generating the gears, and I didn't really feel like doing it all over again. Make sure to apply the displacement modifier after you are satisfied with how the cube looks. Now rotate your cube 90 degrees to the next face, apply the rotation via the Object menu, and repeat the previous two paragraphs until your entire cube is covered in displacement textures as desired. You may need to rotate or flip your textures to align them correctly, but you can just modify the image file and then hit the texture reload button to make that happen. You should run the 3D Printing->Check All test before exporting your finished STL. You don't want any Non Manifold Edges, Bad Contiguous Edges, or Intersecting Faces. I had a few intersecting faces in my model at this point, which I managed to remove by selecting each group of faces, and merging their vertices to a midpoint. You might also want to decimate your geometry if you think your model is too big, but I didn't bother even though I had 400k vertices by this stage. Your final exported cube should be centered at the origin and scaled to approximately 50mm on each edge. Process the cube with the PLA Gear Kit If you've used the PLA Gear Kit before, you probably know that it is not configured by default to turn a unit cube into something that resembles Emmett's cube gears. The axes of the major gears are aligned in a different orientation. Fortunately you can handle this in OpenSCAD with a simple transform. The cube core has four large faces with pins to support the large gears. One of these large face pins lies on the -Z axis, and another pin lies within the X-Z plane, with the result that the cube needs to be oriented as shown below. You could try to do this manually, but it is probably safer to let OpenSCAD handle it for you. The following image shows some code used to point a simple cube in the right orientation, so you just need to replace the cube with an import statement to load your STL instead. After importing and reorienting your cube in OpenSCAD, you can render it and export the fixed STL as the source file for your PLA Gear Kit job. I recommend disabling the small_plate and full_plate tasks in the pla_gear_kit.scad file, because they take a lot longer to complete a task that you can probably do much quicker by hand. You can disable them by removing the part of the comment that says MAKE_TARGET next to the small_plate and full_plate modules. Running the job took almost 20 hours to complete on my old 1.6 Ghz Linux box, not counting screwups, of which I made plenty. I think I was hitting swap pretty hard though. I'm sure someone who understands Blender will know of a better way to do this, but this is what worked for me. Happy landings!