"Have you ever been sitting around bored and found yourself trying to get some random household object — a battery, a pen, whatever — to spin around like a top? Disney has taken that idea to a pretty grand extreme. Combining the power of 3D printing and some damned clever physics work, they’ve worked out a way to make just about any shape spin for ages. The idea: if you have near-perfect control of an object’s distribution of mass, you can also control its center of gravity. Disney just passes in the 3D model and plugs in their spinning axis of choice, and their algorithms figure out what sections of the model’s internals need to be made hollow (or, in some cases, use a heavier printing material) for optimal balance. The bad news: this project was built by Disney’s Swiss research team for the SIGGRAPH 2014 conference, but it doesn’t look like they’re releasing any of the tools they built for others to tinker with. You can read their pdf on the project."
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