STL file, horizontal diamond: http://www.geekhaus.com/makerhome/day180_borr_dia_piece12.stl
STL file, vertical diamond: http://www.geekhaus.com/makerhome/day180_borr_dia_piece3.stl
STL file, all together: http://www.geekhaus.com/makerhome/day180_borr_dia_together.stl
Thingiverse link: http://www.thingiverse.com/make:67201
Settings: MakerWare .3mm/low with no raft or support for the first two pieces, and both raft and support for the vertical piece. The vertical piece is oriented in such a way to need to support on its interior, while forcing support in a small area at its base for stability.
Technical notes: Using the ellipse function and tubify module from Day 179, uncomment the code below to get the type of model you want (single diamonds or all together).
////////////////////////////////////////////////////////////
// Borromean diamonds - all together
////////////////////////////////////////////////////////////
/*
// set faces
$fn=4;
// make the three rings
rotate([0,0,0]) rotate([56.6,56.6,0])
color("red") tubify(r=3,step=90,end=360);
rotate([0,0,120]) rotate([56.6,56.6,0])
color("yellow") tubify(r=3,step=90,end=360);
rotate([0,0,240]) rotate([56.6,56.6,0])
color("blue") tubify(r=3,step=90,end=360);
*/
////////////////////////////////////////////////////////////
// Borromean diamonds - do one at a time and then assemble
////////////////////////////////////////////////////////////
// set faces
$fn=4;
// diamond ring
// print two of these
scale(1.3) tubify(r=3.5,step=90,end=360);
// diamond ring
// print two of these
// scale(1.3) rotate([35,0,0]) rotate([0,90,0]) tubify(r=3.5,step=90,end=360);