So, What's a Kaleidocycle?!

I should be sleeping, but I couldn't resist waiting for this final version print to finish - and it works!  It's aliiiiiive!  Well, not quite, but you'll have to excuse me if I'm super excited about this one - it's been a long road and for most of it I wasn't sure I'd get to a workable end.

So, what is this thing?

Well, it's kind of a ring you can turn inside-out continuously, despite the fact that it merely has a bunch of regular hinges between the parts.  They're traditionally made from paper, where the underlying structure is more evident - a series of tetrahedra (six, in this case), which join via hinges.

In fact, that's how I started - I just modelled a set of six tetrahedra without hinges, sitting with their edges together.  And that started breaking my brain.

Okay, so to some degree the brain breaking was self-inflicted, because there was an easy way out of this all along: make the thing an assembly of individual parts.  And I might still do that!  But no, I wanted to make this thing print-in-place, and that had a few significant issues:

First and foremost, this thing will never lay flat.  The planes of the tetrahedra will never sit on the same plane.  All you can do is get them close, which sounds hopeful until you realise that in 3D printing that just means you're making insane overhang angles!  You see, we can twist and turn the components and decide what configuration to use, but there is no configuration that isn't horrible for printing - make one surface printable and you move another into disaster area.

Second, the hinges.  We have vertical-ish hinges (but not quite) and horizontal-ish hinges floating in mid-air.  The angles of those hinges are tied intimately to the angles of those planes we're trying to keep printable.

Third, the components need to fold into their adjacent component quite tightly, which has significant consequences for hinge design! 

But enough of my doom and gloom!  It works! :D

I've tried to make this as printable as it possibly can be for something that is difficult to make printable at all, but you'll want to make sure that: 

a) your bed adhesion is solid, because it's all balanced from three small points (and the forms never quite touch during printing, so they don't support each other) 

b) your overhangs print okay.  These are still within the realms of normal printing, but there's scope for messiness if things aren't relatively well calibrated.

So, hopefully you're as inspired by this shape as I was, and hopefully you can get it printed without too much trouble!  I'm putting a video up on Instagram shortly if you want to see the thing moving.  

Creative Printer supporters, you'll find the files under Print in Place Kaleidocycle on dropbox.  Oh, and the dropbox URL has been updated, so make sure to grab the new one! :D

Have fun! 

xoxo