Trapped Outside (hollow)

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Trapped Outside (hollow) 3d printed triple intersection point
triple intersection point
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  • White

    White nylon plastic with a matte finish and slight grainy feel.

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This is a model of Boy's Surface, a one-sided surface with no edges and no pinch points.

This is a modified version of Trapped Outside, without the cut-away track or internal ball. This version has a tiny hole at the three-way intersection point so that Shapeways recognizes the internal space as empty and doesn't charge for it. The hole is so small it will not be printed, and the interior will be filled with support material.

Other versions:

The original design is here:

Without the ball:


Remember to give this model five stars if you like it!

© 2011, Matt Chisholm. All rights reserved.


IN: 0.973 w x 1.515 d x 1.417 h
CM: 2.472 w x 3.848 d x 3.6 h


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@hamishtodd1 Cool, thanks. I re-did the place where the pipes join several times before coming to this version, so I'm glad to hear someone else likes it. :) I'll think about doing a bigger version.
June 28, 2013, 8:01 am
One thing I'll say: I was previously worried about the fact that the "pipes" seem to coalesce in a rather rough way, unlike the wikipedia "boy's surface" article picture where they blend into a triangle. But actually, it's good this way. It gives some suggestion that the "rings" are separate - they aren't, but it's helpful to get your head around the structure by first imagining that they are and then seeing where their surface goes.
June 26, 2013, 2:06 pm
This is great, though would be nice if it was a little bigger
June 26, 2013, 1:49 pm


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