This shape demonstrates another application of a double-toroidal loop
-- this time producing a self-intersecting structure.
The shape is equivalent to sweeping a cross-shaped cross-sectional
profile around the toroid and giving it three qurters of a twist before
joining the ends.
This design and fabrication effort is part of a research program sponsored by NSF to streamline the process of rapid prototyping of free form parts, by defining a clean separation and interface between designers and fabricators.
Orientation is not critical either. However, for a layered manufacturing
process (SLA, SLS, etc), it might be best to turn the
object 90 degrees around the x-axis, thereby giving the part
minimal height, and preserving its 3-fold symmetry ideally.
In the .STL file describing this part, the surfaces of the two loop traversals intersect. Thus this is not a proper boundary representation. Thus this requires software that does not get baffled when two polygons in the slicing plane overlap.
The compressed files can be downloaded from our anonymous FTP
site with:
ftp ftp.cs.berkeley.edu {login as "anonymous"; use your full
e-mail address as password.}
Then change directory: cd ucb/projects/unigrafix/STL99
Fetch desired file: get FILE.stl.gz
The FILE.stl.gz file can be uncompressed with gunzip.
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