Oblate Spheroid

Yesterday, I was talking with ChatGPT v4 about certain basic shapes, like cubes, pyramids, and if it could generate STL files for them. It did. It created working STL code for a cube, a pyramid, and a skewed pyramid. So cool!

Today, I was talking with it about how to respond to people who believe the Earth is flat, and we got into a discussion about the actual shape of the Earth, which is an “oblate spheroid.” I asked it how that was defined, and eventually I popped the question: can you make an STL file for me so I can see what an oblate spheroid looks like?

It said it could not. Whomp whoooommmp.

But it did know I use Fusion 360, and gave me directions on how to create one of these oblate spheroids in that program, which I ignored, because then it gave me Python code for creating an STL file based on specific a/b settings, including the correct/approximate settings for creating a model of the Earth.

So I ran the Python code that it generated, and it spat out an STL file.

Now, as I human, I know that we generally can't go printing spheres without rafts using the FDM printing process, but that didn't stop me from trying. Got a nice spaghetti failure. But hey, it's my filament and machine, right?

So I re-printed the model using a 1-layer raft, and that one took! One hour later, I now hold the world in my hands. (Shown.)

If you download this STL, you will have the shape of the Earth (approximately), with none of the messy geometry, land or water. But you'll also know that it's not a sphere…it's an oblate spheroid, and it was generated almost entirely by computer.

As mentioned earlier, you're going to absolutely want to use some bottom support on this. It's possible that if you have an awesome printer with fantastic bed adhesion, you might (might!) be able to print this without supports or a raft or whatever. If you are going to attempt printing this support-free, please monitor the print. There's a very good chance it will fail.

The world is now mine. It can be yours, too.