[WIP] 5-Color Topographical Earth in High Def

prusaprinters

<blockquote><p><strong>This model is untested!</strong> I don't have a multimaterial printer yet :-)</p></blockquote><p>To celebrate the upcoming Prusa XL, this is a 5-color 32cm-diameter globe in high definition, which should be just perfect for that kind of printer.</p><p>It's provided in two versions: one with 3.6 million triangles per hemisphere, which should probably be enough for everyone, and one with 14.6 million triangles in case you have some freak printer from the future.</p><p>The hemispheres have receptacles for connectors that ensure that they align perfectly when glued together.</p><p><i>Have patience:</i> this is slow to load in the slicer, slow to slice, and extremely slow to print - especially in the 14.6 million triangle version.</p><h3>Instructions</h3><h4>Color choices</h4><p>For reference, the original colors of the image used for this model are:</p><ul><li>Water: #0127FF (RGB 1, 39, 255)</li><li>Green: #434329 (RGB 67, 67, 41)</li><li>Dark brown: #8B7455 (RGB 139, 116, 85)</li><li>Light brown: #AE9370 (RGB 174, 147, 112)</li><li>Snow: #E6E6E6 (RGB 230, 230, 230)</li></ul><p>Recommendations:</p><ul><li>First print a small section of the hemispheres, to make sure the colors look good and print well.</li><li>Avoid colors that are too dark, as it would be hard to see the details.</li><li>Likewise, choosing matte colors will probably results in more easily discernable details.</li><li>Don't make the shell too thin, especially if you use light colors, since it can make the infill become visible when the globe is under direct light.</li></ul><h4>Printing instructions</h4><p>The model is detailed enough that using a smaller layer height and/or a smaller nozzle would yield great results, if you can stomach the increase in printing time.</p><p>Supports are not needed. The inner top of the model would look bad, but it's internal anyway.</p><p><strong>I high recommended</strong> first printing a test print to ensure the colors look good and work well. This can be done by changing the model to have zero infill and zero top, bottom and side shells, then adding a box modifier that restores these settings and placing that modifier just on what you want to print.</p><p>Now print both hemispheres, and print four copies of the connectors. The connectors are there for alignment, not structural integrity, so don't worry too much about their print orientation.</p><h4>Assembly instructions</h4><ol><li>Put the southern hemisphere on something stable. I recommend <a href="https://www.printables.com/model/151247-stand-for-a-spherical-object.">https://www.printables.com/model/151247-stand-for-a-spherical-object.</a></li><li>Ensure that both hemispheres fit well with the connectors. If they don't, reprint the connectors, playing around with their scaling until they fit.<ul><li>The connectors are designed to have a tight fit in X and Y, but not in Z.</li></ul></li><li>Apply glue to the bottom of the connectors and place them in the receptacles of the southern hemisphere - this is done to prevent the connectors from rattling, as they are intentionally not tight on Z.</li><li>Apply glue to the base of the southern hemisphere (which is currently its top) and place the other hemisphere on top of it.</li></ol><h3>Generation details</h3><p>Topography data: <a href="https://visibleearth.nasa.gov/images/73934/topography,">https://visibleearth.nasa.gov/images/73934/topography,</a> normalized so that the distance between the highest mountain and sea level is 7mm. Furthermore, any land got a 0.5mm boost over the surrounding shallow waters, to help better differentiate them from each other.</p><p>Bathymetry data: <a href="https://visibleearth.nasa.gov/images/73963/bathymetry,">https://visibleearth.nasa.gov/images/73963/bathymetry,</a> normalized so that the distance between the deepest trench and sea level is 5 mm. The exaggeration is intentionally less than the land elevation data because otherwise a lot of oceanic volcanic mountains become weird spikes.</p><p>Color data is from a NASA composite capture of earth as it was in June 2004: <a href="https://visibleearth.nasa.gov/images/76487/june-blue-marble-next-generation/76492,">https://visibleearth.nasa.gov/images/76487/june-blue-marble-next-generation/76492,</a> quantized to 5 colors and blurred so that there are no tiny regions per color. Blurring can create strange artifacts sometimes (like how India is now connected to Sri Lanka), but it also makes the print less noisy.</p><p>All of the above ignores sea ice, and so does the model.</p><p>Model generation was done via a custom script, and includes color information in both 3MF's Material extension and in slic3r's format, which is also used by PrusaSlicer.</p>