Two treasure chests – 3D printing adventure

3D printing turned out to be a lot of fun, because it involves a challenge of figuring out how to build a model that will print well. This includes very different considerations than creation of game models that have to fit within a budget of polygons and texture resolution. So while I am in this beginner learning phase of 3D printing, I welcomed requests from my kids, who loved the cat and dog models that came ready to print on a memory card. My son requested a treasure chest, so I gave it a shot.

The goal with this first model was to make a working hinge. The treasure chest featured above was created in Maya, then taken to zBrush for detailing. At this point, I still have not used any supports, and have designed this chest to not really need them, although looking at how it came out, some supports for the bridge of the lid would have been helpful. The trunk and the lid were two separate models printed individually, and I made sure to not have the lid side of hinges dip below the rim of the lid so that the lid could be printed sitting flat on the glass plate. It all went well, and I was able to insert top part of hinges into bottom without breaking them, however the lid will not completely close, which may be resolved with some sanding.

In retrospect, I spent way too much time in zBrush detailing the chest, since most of these details were too small to show up distinctly. On the other hand, if I were to paint it with dark color first and then lightly brush on a brighter color, maybe some of these details would start showing better, especially wood grain and phillips-head screws. Here is what the zBrush model looks like:

treasure chest in zBrush

The model of this chest along with low poly version that can be detailed in your favorite sculpting app is available for download at Thingiverse.

My girl loved this chest so much, so she adopted it, and my son said that he actually wants a different chest, the one out of Roblox:

Now that would be some work to clean up and get ready to print. To begin, I launched Roblox Studio, inserted the model of the chest into the scene, then exported the model to .obj. Subsequently, I imported the .obj into Maya and removed the extra edges to turn it into quad based model that will subdivide nicely. Then I replaced the square chain links with the ones I made out of a torus. I also removed the coins and hollowed out the trunk and lid, as well as replaced the hinges with functional ones. This model was to be printed together as one, because of the chain that went all the way to the bottom of the model and around.

I was fiddling quite a bit with the model at this stage, going back and forth between Maya and slicer. It was first time for me to use Cura slicer, because it didn’t have the profile for my printer, and so I copied the specs for my CR6-SE from New Creality Slicer (which turns out to be just an older version of Cura). I decided to give automatic support generation a go, and at that point I had to adjust the inside surface of the lid so that the slicer wouldn’t completely fill the inside of the chest with supports. I also increased the angle for support to 60, and picked a rainbow filament that asked for slightly higher nozzle temperature (200-220F, so I went with 210F). Here’s a short time-lapse of the printing process (click/tap to play):

Printing process with extruder’s LED on

Finally, here is what the rainbow chest looked like when it came out of print and I broke off the support in the rear, and with it a part of the chain and bottom of the hinges >.<:


At this point, I got the chain completely off at request of my son, but I managed to remove the supports between chain links and have a clean 3D printed chain. If I had to print this again, I would print the chain laying flat on the plate and connected to the hoop at the bottom of the chest, seen in middle picture above. That way I could print the lid separately and adjust the design of the hinges to need no support, as I’ve done with the first chest. This rainbow treasure chest, now without chains, is a good piece for me to figure out how to get it to look smooth, which wouldn’t work if I put in all kinds of details as in the first one. So far it was sanded with 400 and 500 grit sandpaper, looking dull and needing much more sanding to get back to slick, shiny surface. I’ll also give acetone a go, and if I end up with anything worth showing, I’ll add a picture here, but that’s all for now.

Edit 02/23/2021 – The first treasure chest is uploaded to Thingiverse and link added to this post, and here’s what this second chest looks like after adding the tiny metal hinges and green foam sheet as a padding:

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