Algorithm to combine triangle meshes into triangle strips

Algorithm to combine triangle meshes into triangle strips

Post by Keith F » Thu, 14 Jul 1994 11:06:45



I am looking for an algorithm to convert a triangle mesh into
triangle strips (to be used for more efficient display on SGI
graphics hardware.)  The triangle mesh, by my definition, is a
set of triangles that share between 1 and 3 edges with another
triangle(s).  A triangle strip, as per the GL/OpenGL format, is
an ordered set of triangles (usually more than two) that share
two edges with neighboring triangles, except for the first and
last triangle in the set who only share edges with one triangle.

Any help would be greatly appreciated.  Thanks in advance.

Keith Fry
University of Michigan

 
 
 

Algorithm to combine triangle meshes into triangle strips

Post by Dirk VanGeld » Thu, 14 Jul 1994 13:43:27


Check out the source for ivquicken, it's an Inventor program that performs
various optimizations on Inventor scene graphs, one of which is to
convert indexed face sets to triangle strip sets. It uses hash functions
which key on x,y,z position to find adjacent edges, remove redundant
polygons, and build the tstrips. You'd have to convert your data structure
to an Inventor one, or rewrite the code, but it's pretty fast. It seems
to have problems with >150,000 polygons or so, don't know why.

I remember seeing some code by Paul Haberli in 4Dgifts that used the
same hash function stuff to make tstrips, probably the basis for the
inventor code.

-Dirk Van Gelder

 Engineering Animation, Inc.