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Nevermarklast Thursday at 4:50 AM2 repliesview on HN

That isn't true.

Look at the pictures. It has the same outer shape, that is all that is required for the geometry.

And for center of mass, you set the positions for the bars, any variations in their thickness, then size and place the flat facet, in order to achieve the same center of mass as for a filled uniform density object of the same geometry.

As the article says:

> carefully calibrated center of mass

Unless an object has internal interactions, for purposes of center of mass you can achieve the uniform-density-equivalent any way you want. It won't change the behavior.


Replies

gus_massalast Thursday at 2:34 PM

> Unless an object has internal interactions, for purposes of center of mass you can achieve the uniform-density-equivalent any way you want. It won't change the behavior.

That is true, but they are using a very heavy material for a small part and very light material for the other. So in this case the center of mass is almost on one of the faces of the polyhedron.

Dylan16807yesterday at 2:44 AM

I'm looking at the pictures. It has voids. The voids (or ultra low density sections) are critical to getting the center of mass where it is.