Back in 2013 I prepared a blog post on 3D printing a moon model using Maya and Mudbox.
A friend of mine named Alex used the same process described in that blog post to create a plastic 3D printed physical model of the moon with exaggerated surface relief for the museum he worked at. This 3D printed lunar model was created as a learning tool for a summer astronomy program in Hong Kong called the “Stargaze Camp for All“. This plastic moon model was used to help visually impaired youth get an understanding of the moon’s surface and to allow them to feel the impact craters and other lunar surface relief details with their hands.
Since this model was designed for use by the visually impaired it was important to add some markings to the mesh so they would be able to easily figure out the earth facing side of the moon and the “upward” orientation for the model. This was achieved with the addition of a dividing line on the model’s surface along with two raised printed letters that were added to the spherical mesh to mark the top and bottom parts of the moon.
During the moon model’s creation stage, Maya’s extrude tool was used to add thickness to the Mudbox generated lunar mesh geometry “shell”. Several alignment pegs were also added in Maya so the two parts would clip together for added strength. The polygon mesh was then exported from Maya as an OBJ format mesh. To make better use of the 3D printer’s capabilities, the physical model was designed so it would be fabricated in two halves so they could be positioned side by side on the printer’s wide aspect ratio shaped platen tray.
Having the lunar surface printed as a hollow two part model also saved resources as less plastic resin was used compared to creating the model as a fully solid object.
The moon model was printed in a special high resolution 3D printer that works by curing an ABS plastic like liquid resin called EnvisionTec Perfactory LS600. The 3D printer machine has two main components that make it work: A high output UV light source that is provided by a DLP video projector like system that is located at the top of the 3D printer, and a liquid resin holding tank with a movable platen tray that is located at the bottom of the printer. As the UV light is projected onto the top layer of the liquid resin it slowly turns the material into a solid plastic.
In order for the 3D printer to create the physical plastic version of the lunar model, the polygon geometry of the moon was broken down into very thin slices that were then sent to the printer as a series of hundreds of greyscale images that were projected as a UV light pattern by the 3D printer onto the UV sensitive liquid resin. As each layer of the design was exposed using high intensity UV light, the plastic resin at the top of the tank cured and the model slowly took shape over many hours. Then the platen tray was lowered down into the tank by a fraction of a millimeter and the next layer of the design was printed in the liquid resin bath.
Once the completed lunar model was taken out of the 3D printer the temporary support structures that the printer added to the model needed to be cleaned up. Finally, the last stage of the model building task was for the two part model to be glued together with an ABS plastic safe adhesive glue.
Fabricating a 3D Printed Moon Model
Here is a quick photo tour of the process of creating the plastic moon model using a 3D printer.
3D Printing the Chang’e 3 Lunar Landing Site
A few weeks later my friend Alex was tasked with 3D printing a model representation of the Chinese Chang’e 3 lunar landing site for an exhibit at the museum. He used a similar approach in Maya to create this model as was used for the previous spherical moon model. I think the final spray painted lunar surface from this project looks amazing!