RE: [rp-ml] RE: A New Route to Smaller 3-D Files

>From the article...

        Computer scientists have struggled with the problem of finding an
optimal mix of large and small elements for years. In 1998, theoreticians
        proved that the problem was "NP hard" that no general solution
exists that can be solved by a computer in finite length of time. They did
        find work-arounds: fast methods to simplify meshes, which were
unable to guarantee accuracy, and accurate techniques, which were too slow.

        The Desbrun teams novel approach comes from the seemingly unrelated
field of machine learning using a technique invented in 1959 called
        Lloyd Clustering named after its inventor Stuart Lloyd. Desbruns
algorithm uses it to automatically segment an object into a group of non-
        overlapping connected regions an instant draft alternative to the
too-numerous triangles of the original scan...->

        ...->The technique turns them instead into an assortment of polygons
-- some triangles, but also four, five, six or more sided figures that
        more efficiently represent the shape. These in turn feed seamlessly
into standard software to represent 3-D shapes on computer screens,
        or for other uses.

If you first optimize the shape into multi-sided polygons (greater than
three) you can theoretically create a mesh that more closely fits the
surface. If you then break the multi-sided polygons into triangles, you
should have an optmized STL mesh.

Larry Blasch
Design Engineer/CAE Systems Administrator
OPW Fueling Components
P.O. Box 405003
Cincinnati, OH 45240-5003 USA
Voice: (513) 870-3356
Fax: (513) 870-3275

-----Original Message-----
From: Deelip Menezes [mailto:deelip@fpsols.com]
Sent: Thursday, June 17, 2004 2:09 PM
To: Blasch, Larry; rp-ml@rapid.lpt.fi
Subject: [rp-ml] RE: A New Route to Smaller 3-D Files

Sounds interesting. It this very different from mesh decimation (face
reduction)?

/Deelip Menezes

-----Original Message-----
From: Blasch, Larry [mailto:LBlasch@OPW-FC.com]
Sent: Thursday, June 17, 2004 9:13 PM
To: 'deelip@fpsols.com'; 'rp-ml@rapid.lpt.fi'
Subject: A New Route to Smaller 3-D Files

A new way to reduce STL file size?

http://www.usc.edu/dept/engineering/news/2004_stories/2004_06_15_desbrun
.htm
l

Graphics Breakthrough Can Benefit Cartoon and Game Creators, Web
Marketers, Virtual Museums and Others

A University of Southern California computer scientist has created a
powerful and elegant algorithm to compress the large and ungainly files
that represent 3-D shapes used in animations, video games and other
computer graphics applications.

Larry Blasch
Design Engineer/CAE Systems Administrator
OPW Fueling Components
P.O. Box 405003
Cincinnati, OH 45240-5003 USA
Voice: (513) 870-3356
Fax: (513) 870-3275
Received on Fri Jun 18 14:58:48 2004